related to the CSU..there is a case for them being 2 pieces.. I had a horrific case in summer (on a RFX38 m2 ) that would have destroyed many frames, but my canfield didnt flinch.. however I could not keep the headset properly tight after couple rides.. after several inspections at the bikeshop and then by myself, the steerer was bent (or pulled forward due to the impact) at the crown/tube interface, measured at 0.3deg, that was enough to throw off all surfaces around the headset.. I did replace it and have a new fork again..
The chassis is the most important part of the fork, starting with subpar tolerances and construction , your fancy damper and air spring are meaningless...
related to the CSU..there is a case for them being 2 pieces.. I had a horrific case in summer (on a RFX38 m2 ) that would...
related to the CSU..there is a case for them being 2 pieces.. I had a horrific case in summer (on a RFX38 m2 ) that would have destroyed many frames, but my canfield didnt flinch.. however I could not keep the headset properly tight after couple rides.. after several inspections at the bikeshop and then by myself, the steerer was bent (or pulled forward due to the impact) at the crown/tube interface, measured at 0.3deg, that was enough to throw off all surfaces around the headset.. I did replace it and have a new fork again..
The chassis is the most important part of the fork, starting with subpar tolerances and construction , your fancy damper and air spring are meaningless...
your last comment is a very good one - no amount of damping magic can compensate for poor alignment & binding - be it from deflection in the lowers or tight bushings.
That's wild. As someone mentioned in another thread (tech rumors I think?), tight tolerances are so hard to get in manufacturing but so important for MTB...
That's wild. As someone mentioned in another thread (tech rumors I think?), tight tolerances are so hard to get in manufacturing but so important for MTB. This fork lower seems like it never should have passed QC.
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).
I've been a bit skeptical the last few years of the trend of home mechanics burnishing and re-sizing their bushings, because in my experience the clearance you want is pretty tight and specific. Seems like a lot of the time users are just hogging them out, which can be just as bad as having tight bushings. And to be clear, there are forks with tight bushings too.
But back to the broader subject, yes the pendulum is swinging back to a focus on damping and perhaps the realization that you can't (and don't want to) do everything with the spring.
Or run an Ohlins or Manitou and get both a supportive air spring and great damping.
The CSUs are still a problem, haven't met one from any brand that can last a full season of hard riding under my stunning mediocrity. I've accepted that CSUs are a wear item and I might just start buying spares when they're in stock. Bring on the enduro dual crowns.
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).I've been a bit skeptical the last few years of the...
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).
I've been a bit skeptical the last few years of the trend of home mechanics burnishing and re-sizing their bushings, because in my experience the clearance you want is pretty tight and specific. Seems like a lot of the time users are just hogging them out, which can be just as bad as having tight bushings. And to be clear, there are forks with tight bushings too.
But back to the broader subject, yes the pendulum is swinging back to a focus on damping and perhaps the realization that you can't (and don't want to) do everything with the spring.
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.
Based on the video and the comments from Diaz, it seems like it wasn't a bushing issue, "Again NO BUSHING BURNISHING NEEDED OR WOULD HAVE EVEN HELPED." Seems like it was a misalignment in the actual casting or a mis-facing of the casting's axle interface that resulted in a twisting of the lowers when the axle was clamped. Could have been the CSU alignment too, but based on the text from Diaz it seems like they think the CSU alignment (while less than perfect) wasn't the issue with this fork- "Measured the uppers at the top and bottom with calipers to see how far out of alignment those were. This is one of the few things actually measurable and again it doesn't mean much. We pretty regularly have to purposely misalign the uppers to run smoothly with the lowers. We have tried getting them perfect and working from there and it rarely works."
I'm also skeptical of suspension tuners that make their name by saying everything from SRAM and Fox HQ is trash (e.g. Rulezman) but either way, this specific fork seems like a lemon. Either the casting was out of spec (Diaz' theory) or the uppers were out of spec (alternate theory), but something on that fork should have been thrown in the garbage on the QC line instead of getting shipped to a customer.
To go back to the original original question in this thread, my thoughts on the current generation of forks is that they're (by and large) phenomenal. I'm super impressed with what's available and I feel like the performance trade-offs you have to choose with any setup are smaller and smaller every year. I've spent a lot of time on the Zeb and 38 and if I was blindfolded I couldn't tell you the difference. The Ohlins DHZXF38 (or whatever their single crown is called) is also great, with a slightly more damped feel. Pepperidge Farm remembers when single crown forks for 29" wheels were really, really bad.
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).I've been a bit skeptical the last few years of the...
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).
I've been a bit skeptical the last few years of the trend of home mechanics burnishing and re-sizing their bushings, because in my experience the clearance you want is pretty tight and specific. Seems like a lot of the time users are just hogging them out, which can be just as bad as having tight bushings. And to be clear, there are forks with tight bushings too.
But back to the broader subject, yes the pendulum is swinging back to a focus on damping and perhaps the realization that you can't (and don't want to) do everything with the spring.
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.Based...
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.
Based on the video and the comments from Diaz, it seems like it wasn't a bushing issue, "Again NO BUSHING BURNISHING NEEDED OR WOULD HAVE EVEN HELPED." Seems like it was a misalignment in the actual casting or a mis-facing of the casting's axle interface that resulted in a twisting of the lowers when the axle was clamped. Could have been the CSU alignment too, but based on the text from Diaz it seems like they think the CSU alignment (while less than perfect) wasn't the issue with this fork- "Measured the uppers at the top and bottom with calipers to see how far out of alignment those were. This is one of the few things actually measurable and again it doesn't mean much. We pretty regularly have to purposely misalign the uppers to run smoothly with the lowers. We have tried getting them perfect and working from there and it rarely works."
I'm also skeptical of suspension tuners that make their name by saying everything from SRAM and Fox HQ is trash (e.g. Rulezman) but either way, this specific fork seems like a lemon. Either the casting was out of spec (Diaz' theory) or the uppers were out of spec (alternate theory), but something on that fork should have been thrown in the garbage on the QC line instead of getting shipped to a customer.
To go back to the original original question in this thread, my thoughts on the current generation of forks is that they're (by and large) phenomenal. I'm super impressed with what's available and I feel like the performance trade-offs you have to choose with any setup are smaller and smaller every year. I've spent a lot of time on the Zeb and 38 and if I was blindfolded I couldn't tell you the difference. The Ohlins DHZXF38 (or whatever their single crown is called) is also great, with a slightly more damped feel. Pepperidge Farm remembers when single crown forks for 29" wheels were really, really bad.
As someone who has some home burnishing equipment at his house (started a couple years ago), it's been pretty nice to have and there seems to be some benefit. However, it does seem that the fork performance tends to "degrade" quicker in between services. I find myself needing to really adhere to the service intervals.
Fun fact about my experience with fork burnishing, I burnished my wife's 34, left the setup the exact same and the first ride we went on with it she complained with how more "squishy" her fork felt, had to go up in pressure and and some damping to get it feeling the way she wanted to again. Which I think is a good thing. I do think people underestimate how much frictional forces impact suspension performance, especially for lighter riders as its a vastly higher percentage.
As for myself, I've been wondering if it's worthwhile to jump ship from Fox to RS (or any other brand) for a while. I've been invested in the Fox fork "ecosystem" via just various tools, and the idea of having to jump ship and get more tools to do basic service has put me off really trying any other brand. But I think the general consensus is that mountain bike suspension is pretty damn good all around, which is probably the best thing for everyone.
As far as shocks go. Get yourself a Telum. Those vorsprung guys are damn wizards.
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).I've been a bit skeptical the last few years of the...
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).
I've been a bit skeptical the last few years of the trend of home mechanics burnishing and re-sizing their bushings, because in my experience the clearance you want is pretty tight and specific. Seems like a lot of the time users are just hogging them out, which can be just as bad as having tight bushings. And to be clear, there are forks with tight bushings too.
But back to the broader subject, yes the pendulum is swinging back to a focus on damping and perhaps the realization that you can't (and don't want to) do everything with the spring.
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.Based...
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.
Based on the video and the comments from Diaz, it seems like it wasn't a bushing issue, "Again NO BUSHING BURNISHING NEEDED OR WOULD HAVE EVEN HELPED." Seems like it was a misalignment in the actual casting or a mis-facing of the casting's axle interface that resulted in a twisting of the lowers when the axle was clamped. Could have been the CSU alignment too, but based on the text from Diaz it seems like they think the CSU alignment (while less than perfect) wasn't the issue with this fork- "Measured the uppers at the top and bottom with calipers to see how far out of alignment those were. This is one of the few things actually measurable and again it doesn't mean much. We pretty regularly have to purposely misalign the uppers to run smoothly with the lowers. We have tried getting them perfect and working from there and it rarely works."
I'm also skeptical of suspension tuners that make their name by saying everything from SRAM and Fox HQ is trash (e.g. Rulezman) but either way, this specific fork seems like a lemon. Either the casting was out of spec (Diaz' theory) or the uppers were out of spec (alternate theory), but something on that fork should have been thrown in the garbage on the QC line instead of getting shipped to a customer.
To go back to the original original question in this thread, my thoughts on the current generation of forks is that they're (by and large) phenomenal. I'm super impressed with what's available and I feel like the performance trade-offs you have to choose with any setup are smaller and smaller every year. I've spent a lot of time on the Zeb and 38 and if I was blindfolded I couldn't tell you the difference. The Ohlins DHZXF38 (or whatever their single crown is called) is also great, with a slightly more damped feel. Pepperidge Farm remembers when single crown forks for 29" wheels were really, really bad.
Put your fork in a vice inverted at 45 degrees, remove the wiper seals and damper airpspring etc so it's just lowers sliding over bushings, and you'll notice with most forks you'll need to pull apart or push together the lowers to get it to slide smoothly down.
I've ridden a Rulezman messed with fork.... outside of mass production... there is some seriously nice suspension available....... Was an Ohlins 38 fork.... made my factory & tuned 38 look like rubbish.
^^^ I've never seen this before, but this sure does make a lot of sense to me. Yet another reason I'm pretty positive (USD) dual crown designs...
^^^ I've never seen this before, but this sure does make a lot of sense to me.
Yet another reason I'm pretty positive (USD) dual crown designs make our lives so much easier. You will always get better alignment and everything is designed to square up with 3 minutes and the right wrench.
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better. Given the parts are machined vs cast, it may be easier to hold better tolerances, which would most likely help - would be interesting to see a comparison in the deflection of a USD fork vs cast lowers.
I've ridden a Rulezman messed with fork.... outside of mass production... there is some seriously nice suspension available.......Was an Ohlins 38 fork.... made my factory &...
I've ridden a Rulezman messed with fork.... outside of mass production... there is some seriously nice suspension available....... Was an Ohlins 38 fork.... made my factory & tuned 38 look like rubbish.
this all makes me wonder how much deflection the Intend forks have when the wheel is installed.
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better...
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better. Given the parts are machined vs cast, it may be easier to hold better tolerances, which would most likely help - would be interesting to see a comparison in the deflection of a USD fork vs cast lowers.
I'd bet it would be. What it comes down to is how many parts you are trying to align in "one part" vs "several parts". Long post coming up. Sorry in advance.
Fork Tubes: In a USD configuration, its very easy to get a single overlapping fork tube aligned properly. Even if you don't go with a floating bushing design, you are far more likely to nail this 10000 out of 10000 times than a single crown setup where you are trying to align multiple things in each phase of the manufacturing process.
Crowns: The crowns in a USD setup is where majority of the alignment takes place. The big difference here is we are relying on two parts (each crown) that is easy to manufacture with high levels of precision. To add, the system intrinsically has "downstream checks" to ensure alignment and the huge benefit of adjustability. IE, I can align each crown to my fork tubes and am not "stuck" with how my forks CSU came from the factory.
Lowers: Obviously, there are no lowers (the way we think of them) in the case of a USD fork. My bet is this is where the problems most commonly come from in a USD SC architecture, and if you think about it, it makes sense. Fork lowers are cast, often out of magnesium alloy, which means they are prone to warping. The lowers have the highly challenging job of aligning the hub, fork tubes and bushing all in one component. What's worse is if anything is off, there is little adjustment avalaible to the consumer (outside the floating axle, or bending stuff). Its not an impossible task, but again, considering the propensity toward warpage + how many "jobs" its doing all at once, its not ideal.
Fork Lugs: In a USD setup, fork lugs are attached to the stanctions. Two big differentials here. First, they aren't cast part of one larger unit, which I'd argue makes it easier to replicate good tolerances. Second, they spin! The nature of them spinning gives you one less thing to worry about during the alignment process.
Floating Axle: Yes, some mountain bike forks have this, and I'm a fan. When you add this to a USD design, it gives you one more adjustment point with respect to alignment.
All in, with reasonable manufacturing processes you are very likely to get perfectly aligned forks with a USD design. Don't believe me? Go through moto forums and look how many people complain about fork alignment (that can't be solved in 3 minutes and a 10mm).
The final benefits? No more creaking CSU assemblies, seals that always have oil lubricating them, less deflection (if done right) and you could adjust offset using crowns. The obvious downside would be weight. I'd wager a good USD dual crown that is reliable would be 1-1.5lbs heavier than a Zeb/38.
Seems clear to me if there is one thing we could have done as a sport to rapidly get to a much better place technologically it would have been to borrow from the moto side 20 years ago. They had geometry and all things suspension pretty dialed (at least way beyond us) all the way back in the year 2000. The funny part is it tends to be culture and strange confirmation bias, not performance, that holds things back. Just go back 10 or 15 years and look what gear editors were saying... "29 inch wheels can't change direction" "64 degree headtube angles are terrible for cornering but great for stability" "38 pound bikes can't go up hill" and of course..."USD forks are flexy..."
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better...
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better. Given the parts are machined vs cast, it may be easier to hold better tolerances, which would most likely help - would be interesting to see a comparison in the deflection of a USD fork vs cast lowers.
I'd bet it would be. What it comes down to is how many parts you are trying to align in "one part" vs "several parts". Long...
I'd bet it would be. What it comes down to is how many parts you are trying to align in "one part" vs "several parts". Long post coming up. Sorry in advance.
Fork Tubes: In a USD configuration, its very easy to get a single overlapping fork tube aligned properly. Even if you don't go with a floating bushing design, you are far more likely to nail this 10000 out of 10000 times than a single crown setup where you are trying to align multiple things in each phase of the manufacturing process.
Crowns: The crowns in a USD setup is where majority of the alignment takes place. The big difference here is we are relying on two parts (each crown) that is easy to manufacture with high levels of precision. To add, the system intrinsically has "downstream checks" to ensure alignment and the huge benefit of adjustability. IE, I can align each crown to my fork tubes and am not "stuck" with how my forks CSU came from the factory.
Lowers: Obviously, there are no lowers (the way we think of them) in the case of a USD fork. My bet is this is where the problems most commonly come from in a USD SC architecture, and if you think about it, it makes sense. Fork lowers are cast, often out of magnesium alloy, which means they are prone to warping. The lowers have the highly challenging job of aligning the hub, fork tubes and bushing all in one component. What's worse is if anything is off, there is little adjustment avalaible to the consumer (outside the floating axle, or bending stuff). Its not an impossible task, but again, considering the propensity toward warpage + how many "jobs" its doing all at once, its not ideal.
Fork Lugs: In a USD setup, fork lugs are attached to the stanctions. Two big differentials here. First, they aren't cast part of one larger unit, which I'd argue makes it easier to replicate good tolerances. Second, they spin! The nature of them spinning gives you one less thing to worry about during the alignment process.
Floating Axle: Yes, some mountain bike forks have this, and I'm a fan. When you add this to a USD design, it gives you one more adjustment point with respect to alignment.
All in, with reasonable manufacturing processes you are very likely to get perfectly aligned forks with a USD design. Don't believe me? Go through moto forums and look how many people complain about fork alignment (that can't be solved in 3 minutes and a 10mm).
The final benefits? No more creaking CSU assemblies, seals that always have oil lubricating them, less deflection (if done right) and you could adjust offset using crowns. The obvious downside would be weight. I'd wager a good USD dual crown that is reliable would be 1-1.5lbs heavier than a Zeb/38.
Seems clear to me if there is one thing we could have done as a sport to rapidly get to a much better place technologically it would have been to borrow from the moto side 20 years ago. They had geometry and all things suspension pretty dialed (at least way beyond us) all the way back in the year 2000. The funny part is it tends to be culture and strange confirmation bias, not performance, that holds things back. Just go back 10 or 15 years and look what gear editors were saying... "29 inch wheels can't change direction" "64 degree headtube angles are terrible for cornering but great for stability" "38 pound bikes can't go up hill" and of course..."USD forks are flexy..."
all very good points, the fact that the stanchions aren't constrained to one another like cast lowers are hadn't dawned on me.
that does raise another question - in a stand they would have better alignment, however given their known (speculated?) tendency to have more flex (torsional, etc) under load (eg actual riding), would that negate any alignment benefits in a real world scenario?
One thing to add and one question...1) I'd love to see an end to the creaking CSU. This continues to happen to me and I hate...
One thing to add and one question...
1) I'd love to see an end to the creaking CSU. This continues to happen to me and I hate it. Off topic, I know, but this is my #1 compliant.
2) For those playing with setups, how are you assessing "good"? Just going off feel? Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?
I say all of this well aware how easy I am to "trick" into thinking I have a great setup, but really I'm just riding better (or worse...or tired/hungover/overtrained etc)
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the conversation.
“Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?”
Unfortunately we can’t control all the variance with clever experimental design. It’s not a personal failing on anyone’s part but in the nature of the phenomenon (people riding bikes on trails) being sampled. The last resort is to deal with variance. Mountain biking is entering this period of empiricism but attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools.
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the...
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the conversation.
“Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?”
Unfortunately we can’t control all the variance with clever experimental design. It’s not a personal failing on anyone’s part but in the nature of the phenomenon (people riding bikes on trails) being sampled. The last resort is to deal with variance. Mountain biking is entering this period of empiricism but attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools.
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're saying, I'm just asking for a friend who's not as smart as you and me.
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the...
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the conversation.
“Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?”
Unfortunately we can’t control all the variance with clever experimental design. It’s not a personal failing on anyone’s part but in the nature of the phenomenon (people riding bikes on trails) being sampled. The last resort is to deal with variance. Mountain biking is entering this period of empiricism but attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools.
Thanks so much for the kind words. I'm always shocked anyone reads anything I write. I fully agree with you measuring "underlying performance" objectively in the mountain bike world is very (very) hard (if not impossible given resource/business constraints).
In any event, I agree with Robot, unpack your last sentence for those of us who aren't as smart as you. (ahem...me)
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the...
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the conversation.
“Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?”
Unfortunately we can’t control all the variance with clever experimental design. It’s not a personal failing on anyone’s part but in the nature of the phenomenon (people riding bikes on trails) being sampled. The last resort is to deal with variance. Mountain biking is entering this period of empiricism but attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools.
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're...
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're saying, I'm just asking for a friend who's not as smart as you and me.
my rough translation is that the average rider probably things data collection via telemetry is akin to voodoo. or at the very least the cost-v-benefit isn't there (to them at least).
I have also noticed the tolerance situation of CSU vs lowers, bought the bushing sizing tool, used it, didn't make a sizeable improvement. I think that fork probably had some misalignment.
I also think the above discussion about tolerances also highlights that there are some riders now that are sensitive enough to feel imperfect tolerances. I think it's best to realize that the mass produced forks are exactly that, and they're made to satisfy most riders.
My solution was to buy a Push NineOne. That fork rides great and I would guess a chunk of the cost and design is for ensuring tight tolerances and alignment.
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're...
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're saying, I'm just asking for a friend who's not as smart as you and me.
I don't know about smart, but I know it's shtty of me to act like I can read people's minds. I don't really know how people are thinking about this. But it comes up a fair amount and it seems like the next logical step for everyone who is measuring bike stuff.
The questions we can see being asked about bike performance seem totally legit to me. Which PB bike test bike gets up the impossible climb fastest? Did my lap times improve when I changed tires? Did the rider of the DH bike with the tuned mass damper experience less acceleration at the handlebar than a non-TMD bike? Does the Epic 8 transmit less bump force to the rider than the Epic 7? There's a thousand more like these. And the people working on them aren't dumb; we can see they've done some homework. They're measuring an outcome that makes sense. They're showing the data in a way that tells us an answer to the question, like A was better than B, and these stories seem to resonate with a lot of people. There are hella data visualizations and quantitative arguments in mountain biking right now.
The (possibly unfair) criticism I have for where the industry(?) media(?) us(?) is currently is that these data don't really support any "A was better than B" story that includes the inference that A was better than B because of a difference in the properties of A and B. The reason isn't a secret. It's right in jeff.brines' question about how do you control for factors other than your preferred explanation (like the variable you want ultimately to assign to be the cause of the difference in outcomes you measure). If there are several candidate explanations (causes) for the difference, you can't just pick the one you like. There are methods for distinguishing among them. If several factors co-contribute to the difference, there are tools for teasing them apart to get a sense of the size of each factors contribution to the difference. If your test rider's times on setup A vary from run to run (and they do!), then you are on shaky ground ignoring that between-runs variation and progressing straight to timing a lap on setup B and then telling the story of how A < B or B > A. All these data tools are way cheaper than power meters and suspension DA kits and bespoke accelerometry sensor packs or whatever the next hot thing may be. Those things are cool, but I feel it raises the question don't you want to use them better? I get how your test rider maybe doesn't want to do 20 runs. And time is money. But when you've already got the DA or the editorial staff all out on the big hill or have convened a meeting of the Specialized University Science Masters why are we suddenly in a rush and doing obviously substandard work?
I really kinda want to know which bike gets up the hill quickest :D
Since we are talking creaking CSUs, is there a particular reason why crown cannot be made as one piece? (I believe there were some full carbon...
Since we are talking creaking CSUs, is there a particular reason why crown cannot be made as one piece? (I believe there were some full carbon csu-s in xc)
Ohlins used to do this on the RXF 36 back in 2017-2018. I'm running one right now with the m.2 lowers and internals. They even included the crown race into the shape of the steer tube. Literally zero flex points for it to creak. It was brilliant in my opinion but too many people complained that they couldn't run their headset of choice.
Since we are talking creaking CSUs, is there a particular reason why crown cannot be made as one piece? (I believe there were some full carbon...
Since we are talking creaking CSUs, is there a particular reason why crown cannot be made as one piece? (I believe there were some full carbon csu-s in xc)
here's a link to a bike I built not too long ago that had what Ohlins use to call the 'unicrown' CSU and the m.2 lowers and internals. The lowers had the bushings resized and custom damper tune. I think this combination is one of the best single crown forks on the market.
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.Based...
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.
Based on the video and the comments from Diaz, it seems like it wasn't a bushing issue, "Again NO BUSHING BURNISHING NEEDED OR WOULD HAVE EVEN HELPED." Seems like it was a misalignment in the actual casting or a mis-facing of the casting's axle interface that resulted in a twisting of the lowers when the axle was clamped. Could have been the CSU alignment too, but based on the text from Diaz it seems like they think the CSU alignment (while less than perfect) wasn't the issue with this fork- "Measured the uppers at the top and bottom with calipers to see how far out of alignment those were. This is one of the few things actually measurable and again it doesn't mean much. We pretty regularly have to purposely misalign the uppers to run smoothly with the lowers. We have tried getting them perfect and working from there and it rarely works."
I'm also skeptical of suspension tuners that make their name by saying everything from SRAM and Fox HQ is trash (e.g. Rulezman) but either way, this specific fork seems like a lemon. Either the casting was out of spec (Diaz' theory) or the uppers were out of spec (alternate theory), but something on that fork should have been thrown in the garbage on the QC line instead of getting shipped to a customer.
To go back to the original original question in this thread, my thoughts on the current generation of forks is that they're (by and large) phenomenal. I'm super impressed with what's available and I feel like the performance trade-offs you have to choose with any setup are smaller and smaller every year. I've spent a lot of time on the Zeb and 38 and if I was blindfolded I couldn't tell you the difference. The Ohlins DHZXF38 (or whatever their single crown is called) is also great, with a slightly more damped feel. Pepperidge Farm remembers when single crown forks for 29" wheels were really, really bad.
When I had my Zeb done by Craig at Avalanche I asked him about re-sizing the bushings. He pretty much laughed and said that’s not really a thing for the most part but that he does check every fork that comes to him for a damper install just in case. My fork was fine.
I am stoked to see the damper forward setup starting to gain momentum. As a kid, I grew up riding and racing haresrambles on the east coast. The first thing we did to every bike was have the forks and shock re-valved and different springs installed. Our suspension guy swore by the philosophy that the spring's only job was to hold the bike up, the damper does all the work. That set up still was hit and miss for people, TBH. Some people (me included) loved it. The bike was glued to the ground. You went through 1/3 or more of the travel almost instantly. It was a magic carpet ride over the east coast root and rocks. However, some of the "pro riders" complained that the set up was too slow/soft and it made the bike sluggish. As we all know, pros and cons to everything. But, IMO, that style of suspension is better suited and safer for 95% of riders. I have found the Ohlins shock gets the MTB to ride like what I am used to in moto land. Fork.. still leaves alot to be desired (currently on a Zebb and would like to try the ohlins fork)
My father grew up racing MX in Florida and southern California back in the late 70s. (Honda Elsinore, the first mono shock Yz250, etc) Every time I start talking about the MTB tech he just laughs at me. "We solved these problems in the 80s" As much as you hate to admit when you parents are right... Its funny to see the MTB tech slowly following the trend of the moto tech. (just 40 years behind - ish) Moto started with air forks to keep the weight down cause the frames were so damn flexy. As the frame stiffness got better, weight wasnt such an issue. Then the air canister science got absolutely absurd as they battled over heating and inconsistent ride quality during the moto. The tech moved to coil and air was never used again. Then somewhere around the mid 90s the speeds and terrain got such that the conventional forks just wouldn't cut it and the USD's took over.
I laugh when I go back and watch the FOX dialed videos from a few years back. At one point Jordy said that MTB has no need for coil suspension. And at that time 90% of the DH field was on air shocks. Now... I feel its the other way around.
So as suspension tech evolves, and as others said, the MTB "we have always done it this way" fades away.. I think we will see the suspension tech drift closer to more damped set ups. (USD forks that are also coil)
Side note. Its also interesting to compare MTB geo to moto geo. Same pattern is emerging. The moto started with longer reach and wide bars to get "leverage and stability" But this was all due to suspension limitations (ie the short travel, double shocks and short swing arms) Then watch as the suspension changes, so does the geo. We see wheel base grow, the swing arms (chain stays) grow, and the reach seems to fall back while the stack comes up. IMHO I think we are currently stuck somewhere in the mid 80s of moto tech and geo. USD's with full coils are coming, as are longer chain stays and more balanced frame GEOs.
Again, my opinion and there are lots of variables at play. Motor vs pedaling efficiency, terrain, etc etc.
Slightly off topic, but what I don't understand is why we continue to go the route of press fit CSUs. There has to be a better...
Slightly off topic, but what I don't understand is why we continue to go the route of press fit CSUs. There has to be a better solution. Also, plenty of people (myself included) used to say "it just creaks, at least it won't fail" which I now do not belive to be true. I've seen CSUs go from creaking to the steerer coming out of the crown (Fox). Some ideas...
1) Explore the use of an adhesive: Whether something like Lord's adhesive, which is strong enough to bond critical chassis components together in snowmobiles and cars or something else, this would lock the CSU together.
2) Use complex geometries: Increase surface area and make the pieces "lock" together. Upside here would also be you could mark your steerer tube "0 degree" so your stem is always straight.
3) Weld it. No idea if it'd work.
4) Seal it. I know we all think it comes from alloy on alloy/oxidation, but for whatever reason I still feel dust is partially the culprit. What if the interace was simply sealed using an industrial slow cure epoxy/hot glue/any glue that can flex?
5) Make them two parts and use a bolted interface. Why wouldn't this work? I'd happily take a weight penalty. I also know the creak can come from the stanction to crown interface, but I still say this is something we ought to be able to bolt?
6) One piece CSU. Already mentioned. I don't see how you do this in a cost effective way tbh unless its carbon, which has its own issues. (and would still be pricey)
7) We stop this nonsense and start riding dual crowns for everything over 160mm. I've long said this. I know, everyone will complain about turning radius and the lack of being able to do an x-up, but I ride a dirt bike a lot and could care less about either - and have zero issues going around tight switchbacks.
Feel free to kick this into its own thread but this has been a problem forever.
i don't personally have experience with them - but has anyone experienced CSU creaking on an EXT fork? those have an extended sleeve at the crown...
i don't personally have experience with them - but has anyone experienced CSU creaking on an EXT fork? those have an extended sleeve at the crown / steerer interface and is advertised to reduce creaking, wondering if that actually delivers as claimed.
My V1 Era started creaking after 1 summer and was warrantied. First set of V2 lowers got super sloppy in like a month. Nobody is immune to issues. I ride pretty hard but only weigh 155lbs.
I’ll probably jinx myself but my e-bike came with one of the big 1.8” CSU Zebs and after 2 seasons of smashing steep laps on that 56lb beast it’s still quiet.
Would it work to test bushing sizing by only having one stanchion inserted at a time? It seems like if the resistance you feel is higher when fully assembled is higher than with a single stanchion, the issue is with alignment. Or are there other factors that would influence that?
i think the tolerance stacking of the interface between the dropouts and hub width would also be a factor. a bigger gap would result in more...
i think the tolerance stacking of the interface between the dropouts and hub width would also be a factor. a bigger gap would result in more deflection.
That is true, sometimes spacing the hub 0.15mm wider is all it takes to get the stanchions to drop in the lowers. I worked at DSD for a few years and pulled many forks apart for chassis/bushing "adjustment". Fox is far and away the worse, I'd say 90% had some degree of binding. For RS it was more like 30-40%.
The Fox floating axle system seems to have issues with the axle bore alignment between legs. They will be fine until you tighten the pinch bolt, then it binds. Hard one to fix as well as it seems to be a twist you have to correct and not a splay as is typical.
Next time you do a lower leg service; pull out the old seals, clean the lowers really well, pull the air spring & damper, put a front wheel in the lowers and drop the stanchions. The result can be shocking. 💩
Would it work to test bushing sizing by only having one stanchion inserted at a time? It seems like if the resistance you feel is higher...
Would it work to test bushing sizing by only having one stanchion inserted at a time? It seems like if the resistance you feel is higher when fully assembled is higher than with a single stanchion, the issue is with alignment. Or are there other factors that would influence that?
Yep, you can check the actual bushing fit individually, but it is rarely that bad. It's the chassis alignment that causes the majority of the binding.
Opening up the bushings by burnishing can help, but it isn't solving the real problem.
All RS forks I've tried had no mid stroke spring support, too fast HSR when setting the LSR to my liking. All fox forks were harsh. That's boxxer 35, zeb, fox36, 38gen1. Not tried the newest from the big 2 yet. But the ohlins forks have been bang on fresh out of box within clicker adjustable range
Great stuff people are talking and DSD is showing these issues in MTB space. Watching PeakTorque, Hambini and MapdecCycles videos on YT this isn't surprising at all. Bike manufacturers inability to adhere to dimensional tolerances and QC their products is the sole reason press fit bottom brackets were so hated. Hell, I don't even think most product managers in the industry know what dimensional tolerance is. Make people overwhelm with features, shiny stuff, grams, compliance and stiffness claims, and them sell them shit so OFF, it negates any of the mentioned advantages.
From my own garage: - painted bearing landings - painted and wonky brake mounts - misaligned BB - headset bearings clunking around - bearings eating themselves alive from misalignment - bearings eating themselves alive from from residing in a tight hole - rear dropouts misaligned, ones so wide apart the wheel cannot rest in them - broken freehub pawls on a first ride From my part time mechanic job: - endless creak chasing with customers - gluing in bearings so they dont move about causing creaks or simply fall out - non stop stream of misaligned brake mounts, resulting in little to no pad clearance
I have had it... My next bikes both Gravel and MTB will be basic frames made by small/custom manufacturer who has the tools and expertise to finish up the frame. Suspension can be used to save cash and sent straight to someone who can unfuck-it like DSD.
Ha, fun reading!Great stuff people are talking and DSD is showing these issues in MTB space.Watching PeakTorque, Hambini and MapdecCycles videos on YT this isn't...
Ha, fun reading!
Great stuff people are talking and DSD is showing these issues in MTB space. Watching PeakTorque, Hambini and MapdecCycles videos on YT this isn't surprising at all. Bike manufacturers inability to adhere to dimensional tolerances and QC their products is the sole reason press fit bottom brackets were so hated. Hell, I don't even think most product managers in the industry know what dimensional tolerance is. Make people overwhelm with features, shiny stuff, grams, compliance and stiffness claims, and them sell them shit so OFF, it negates any of the mentioned advantages.
From my own garage: - painted bearing landings - painted and wonky brake mounts - misaligned BB - headset bearings clunking around - bearings eating themselves alive from misalignment - bearings eating themselves alive from from residing in a tight hole - rear dropouts misaligned, ones so wide apart the wheel cannot rest in them - broken freehub pawls on a first ride From my part time mechanic job: - endless creak chasing with customers - gluing in bearings so they dont move about causing creaks or simply fall out - non stop stream of misaligned brake mounts, resulting in little to no pad clearance
I have had it... My next bikes both Gravel and MTB will be basic frames made by small/custom manufacturer who has the tools and expertise to finish up the frame. Suspension can be used to save cash and sent straight to someone who can unfuck-it like DSD.
And you didn't even work in the industry, you would have been socked. I did, I get fired 🙂
related to the CSU..there is a case for them being 2 pieces.. I had a horrific case in summer (on a RFX38 m2 ) that would have destroyed many frames, but my canfield didnt flinch.. however I could not keep the headset properly tight after couple rides.. after several inspections at the bikeshop and then by myself, the steerer was bent (or pulled forward due to the impact) at the crown/tube interface, measured at 0.3deg, that was enough to throw off all surfaces around the headset.. I did replace it and have a new fork again..
The chassis is the most important part of the fork, starting with subpar tolerances and construction , your fancy damper and air spring are meaningless...
your last comment is a very good one - no amount of damping magic can compensate for poor alignment & binding - be it from deflection in the lowers or tight bushings.
It's probably not the casting (the lowers) that's the issue, it's the stanchion alignment (the CSU).
I've been a bit skeptical the last few years of the trend of home mechanics burnishing and re-sizing their bushings, because in my experience the clearance you want is pretty tight and specific. Seems like a lot of the time users are just hogging them out, which can be just as bad as having tight bushings. And to be clear, there are forks with tight bushings too.
But back to the broader subject, yes the pendulum is swinging back to a focus on damping and perhaps the realization that you can't (and don't want to) do everything with the spring.
Or run an Ohlins or Manitou and get both a supportive air spring and great damping.
The CSUs are still a problem, haven't met one from any brand that can last a full season of hard riding under my stunning mediocrity. I've accepted that CSUs are a wear item and I might just start buying spares when they're in stock. Bring on the enduro dual crowns.
Totally, I'm also skeptical of home burnishing wizards and how much of the Great Bushing Epidemic of 2024 is real vs. imagined for social media noise.
Based on the video and the comments from Diaz, it seems like it wasn't a bushing issue, "Again NO BUSHING BURNISHING NEEDED OR WOULD HAVE EVEN HELPED." Seems like it was a misalignment in the actual casting or a mis-facing of the casting's axle interface that resulted in a twisting of the lowers when the axle was clamped. Could have been the CSU alignment too, but based on the text from Diaz it seems like they think the CSU alignment (while less than perfect) wasn't the issue with this fork- "Measured the uppers at the top and bottom with calipers to see how far out of alignment those were. This is one of the few things actually measurable and again it doesn't mean much. We pretty regularly have to purposely misalign the uppers to run smoothly with the lowers. We have tried getting them perfect and working from there and it rarely works."
I'm also skeptical of suspension tuners that make their name by saying everything from SRAM and Fox HQ is trash (e.g. Rulezman) but either way, this specific fork seems like a lemon. Either the casting was out of spec (Diaz' theory) or the uppers were out of spec (alternate theory), but something on that fork should have been thrown in the garbage on the QC line instead of getting shipped to a customer.
To go back to the original original question in this thread, my thoughts on the current generation of forks is that they're (by and large) phenomenal. I'm super impressed with what's available and I feel like the performance trade-offs you have to choose with any setup are smaller and smaller every year. I've spent a lot of time on the Zeb and 38 and if I was blindfolded I couldn't tell you the difference. The Ohlins DHZXF38 (or whatever their single crown is called) is also great, with a slightly more damped feel. Pepperidge Farm remembers when single crown forks for 29" wheels were really, really bad.
As someone who has some home burnishing equipment at his house (started a couple years ago), it's been pretty nice to have and there seems to be some benefit. However, it does seem that the fork performance tends to "degrade" quicker in between services. I find myself needing to really adhere to the service intervals.
Fun fact about my experience with fork burnishing, I burnished my wife's 34, left the setup the exact same and the first ride we went on with it she complained with how more "squishy" her fork felt, had to go up in pressure and and some damping to get it feeling the way she wanted to again. Which I think is a good thing. I do think people underestimate how much frictional forces impact suspension performance, especially for lighter riders as its a vastly higher percentage.
As for myself, I've been wondering if it's worthwhile to jump ship from Fox to RS (or any other brand) for a while. I've been invested in the Fox fork "ecosystem" via just various tools, and the idea of having to jump ship and get more tools to do basic service has put me off really trying any other brand. But I think the general consensus is that mountain bike suspension is pretty damn good all around, which is probably the best thing for everyone.
As far as shocks go. Get yourself a Telum. Those vorsprung guys are damn wizards.
Put your fork in a vice inverted at 45 degrees, remove the wiper seals and damper airpspring etc so it's just lowers sliding over bushings, and you'll notice with most forks you'll need to pull apart or push together the lowers to get it to slide smoothly down.
I've ridden a Rulezman messed with fork.... outside of mass production... there is some seriously nice suspension available.......
Was an Ohlins 38 fork.... made my factory & tuned 38 look like rubbish.
i wanted to touch on your second point re: USD forks - i'm not sure the difference in orientation would necessarily be inherently that much better. Given the parts are machined vs cast, it may be easier to hold better tolerances, which would most likely help - would be interesting to see a comparison in the deflection of a USD fork vs cast lowers.
this all makes me wonder how much deflection the Intend forks have when the wheel is installed.
I'd bet it would be. What it comes down to is how many parts you are trying to align in "one part" vs "several parts". Long post coming up. Sorry in advance.
Fork Tubes: In a USD configuration, its very easy to get a single overlapping fork tube aligned properly. Even if you don't go with a floating bushing design, you are far more likely to nail this 10000 out of 10000 times than a single crown setup where you are trying to align multiple things in each phase of the manufacturing process.
Crowns: The crowns in a USD setup is where majority of the alignment takes place. The big difference here is we are relying on two parts (each crown) that is easy to manufacture with high levels of precision. To add, the system intrinsically has "downstream checks" to ensure alignment and the huge benefit of adjustability. IE, I can align each crown to my fork tubes and am not "stuck" with how my forks CSU came from the factory.
Lowers: Obviously, there are no lowers (the way we think of them) in the case of a USD fork. My bet is this is where the problems most commonly come from in a USD SC architecture, and if you think about it, it makes sense. Fork lowers are cast, often out of magnesium alloy, which means they are prone to warping. The lowers have the highly challenging job of aligning the hub, fork tubes and bushing all in one component. What's worse is if anything is off, there is little adjustment avalaible to the consumer (outside the floating axle, or bending stuff). Its not an impossible task, but again, considering the propensity toward warpage + how many "jobs" its doing all at once, its not ideal.
Fork Lugs: In a USD setup, fork lugs are attached to the stanctions. Two big differentials here. First, they aren't cast part of one larger unit, which I'd argue makes it easier to replicate good tolerances. Second, they spin! The nature of them spinning gives you one less thing to worry about during the alignment process.
Floating Axle: Yes, some mountain bike forks have this, and I'm a fan. When you add this to a USD design, it gives you one more adjustment point with respect to alignment.
All in, with reasonable manufacturing processes you are very likely to get perfectly aligned forks with a USD design. Don't believe me? Go through moto forums and look how many people complain about fork alignment (that can't be solved in 3 minutes and a 10mm).
The final benefits? No more creaking CSU assemblies, seals that always have oil lubricating them, less deflection (if done right) and you could adjust offset using crowns. The obvious downside would be weight. I'd wager a good USD dual crown that is reliable would be 1-1.5lbs heavier than a Zeb/38.
Seems clear to me if there is one thing we could have done as a sport to rapidly get to a much better place technologically it would have been to borrow from the moto side 20 years ago. They had geometry and all things suspension pretty dialed (at least way beyond us) all the way back in the year 2000. The funny part is it tends to be culture and strange confirmation bias, not performance, that holds things back. Just go back 10 or 15 years and look what gear editors were saying... "29 inch wheels can't change direction" "64 degree headtube angles are terrible for cornering but great for stability" "38 pound bikes can't go up hill" and of course..."USD forks are flexy..."
all very good points, the fact that the stanchions aren't constrained to one another like cast lowers are hadn't dawned on me.
that does raise another question - in a stand they would have better alignment, however given their known (speculated?) tendency to have more flex (torsional, etc) under load (eg actual riding), would that negate any alignment benefits in a real world scenario?
I like your posts, jeff.brines. This is a good question whether it was straightforward request for info or a kindly way of adding something to the conversation.
“Any objectiveness (IE, timing/PRing stuff) added to the equation? If so how do you control for conditions, fitness getting better etc.?”
Unfortunately we can’t control all the variance with clever experimental design. It’s not a personal failing on anyone’s part but in the nature of the phenomenon (people riding bikes on trails) being sampled. The last resort is to deal with variance. Mountain biking is entering this period of empiricism but attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools.
"Attitudes about the math-probability-statistics tools haven’t shifted in step with attitudes about the measuring tools." Please expand on this thought. Of course I know what you're saying, I'm just asking for a friend who's not as smart as you and me.
Thanks so much for the kind words. I'm always shocked anyone reads anything I write. I fully agree with you measuring "underlying performance" objectively in the mountain bike world is very (very) hard (if not impossible given resource/business constraints).
In any event, I agree with Robot, unpack your last sentence for those of us who aren't as smart as you. (ahem...me)
One of the biggest complaints of the RS-1 was how fiddly the wheel install was…
There are lots of trade offs to manage with either design, some are 100% not performance based but important regardless.
my rough translation is that the average rider probably things data collection via telemetry is akin to voodoo. or at the very least the cost-v-benefit isn't there (to them at least).
I have also noticed the tolerance situation of CSU vs lowers, bought the bushing sizing tool, used it, didn't make a sizeable improvement. I think that fork probably had some misalignment.
I also think the above discussion about tolerances also highlights that there are some riders now that are sensitive enough to feel imperfect tolerances. I think it's best to realize that the mass produced forks are exactly that, and they're made to satisfy most riders.
My solution was to buy a Push NineOne. That fork rides great and I would guess a chunk of the cost and design is for ensuring tight tolerances and alignment.
I don't know about smart, but I know it's shtty of me to act like I can read people's minds. I don't really know how people are thinking about this. But it comes up a fair amount and it seems like the next logical step for everyone who is measuring bike stuff.
The questions we can see being asked about bike performance seem totally legit to me. Which PB bike test bike gets up the impossible climb fastest? Did my lap times improve when I changed tires? Did the rider of the DH bike with the tuned mass damper experience less acceleration at the handlebar than a non-TMD bike? Does the Epic 8 transmit less bump force to the rider than the Epic 7? There's a thousand more like these. And the people working on them aren't dumb; we can see they've done some homework. They're measuring an outcome that makes sense. They're showing the data in a way that tells us an answer to the question, like A was better than B, and these stories seem to resonate with a lot of people. There are hella data visualizations and quantitative arguments in mountain biking right now.
The (possibly unfair) criticism I have for where the industry(?) media(?) us(?) is currently is that these data don't really support any "A was better than B" story that includes the inference that A was better than B because of a difference in the properties of A and B. The reason isn't a secret. It's right in jeff.brines' question about how do you control for factors other than your preferred explanation (like the variable you want ultimately to assign to be the cause of the difference in outcomes you measure). If there are several candidate explanations (causes) for the difference, you can't just pick the one you like. There are methods for distinguishing among them. If several factors co-contribute to the difference, there are tools for teasing them apart to get a sense of the size of each factors contribution to the difference. If your test rider's times on setup A vary from run to run (and they do!), then you are on shaky ground ignoring that between-runs variation and progressing straight to timing a lap on setup B and then telling the story of how A < B or B > A. All these data tools are way cheaper than power meters and suspension DA kits and bespoke accelerometry sensor packs or whatever the next hot thing may be. Those things are cool, but I feel it raises the question don't you want to use them better? I get how your test rider maybe doesn't want to do 20 runs. And time is money. But when you've already got the DA or the editorial staff all out on the big hill or have convened a meeting of the Specialized University Science Masters why are we suddenly in a rush and doing obviously substandard work?
I really kinda want to know which bike gets up the hill quickest :D
Ohlins used to do this on the RXF 36 back in 2017-2018. I'm running one right now with the m.2 lowers and internals. They even included the crown race into the shape of the steer tube. Literally zero flex points for it to creak. It was brilliant in my opinion but too many people complained that they couldn't run their headset of choice.
here's a link to a bike I built not too long ago that had what Ohlins use to call the 'unicrown' CSU and the m.2 lowers and internals. The lowers had the bushings resized and custom damper tune. I think this combination is one of the best single crown forks on the market.
https://www.vitalmtb.com/community/mscofield4/2020-knolly-fugitive?keyw…
When I had my Zeb done by Craig at Avalanche I asked him about re-sizing the bushings. He pretty much laughed and said that’s not really a thing for the most part but that he does check every fork that comes to him for a damper install just in case. My fork was fine.
I am stoked to see the damper forward setup starting to gain momentum. As a kid, I grew up riding and racing haresrambles on the east coast. The first thing we did to every bike was have the forks and shock re-valved and different springs installed. Our suspension guy swore by the philosophy that the spring's only job was to hold the bike up, the damper does all the work. That set up still was hit and miss for people, TBH. Some people (me included) loved it. The bike was glued to the ground. You went through 1/3 or more of the travel almost instantly. It was a magic carpet ride over the east coast root and rocks. However, some of the "pro riders" complained that the set up was too slow/soft and it made the bike sluggish. As we all know, pros and cons to everything. But, IMO, that style of suspension is better suited and safer for 95% of riders. I have found the Ohlins shock gets the MTB to ride like what I am used to in moto land. Fork.. still leaves alot to be desired (currently on a Zebb and would like to try the ohlins fork)
My father grew up racing MX in Florida and southern California back in the late 70s. (Honda Elsinore, the first mono shock Yz250, etc) Every time I start talking about the MTB tech he just laughs at me. "We solved these problems in the 80s" As much as you hate to admit when you parents are right... Its funny to see the MTB tech slowly following the trend of the moto tech. (just 40 years behind - ish) Moto started with air forks to keep the weight down cause the frames were so damn flexy. As the frame stiffness got better, weight wasnt such an issue. Then the air canister science got absolutely absurd as they battled over heating and inconsistent ride quality during the moto. The tech moved to coil and air was never used again.
Then somewhere around the mid 90s the speeds and terrain got such that the conventional forks just wouldn't cut it and the USD's took over.
I laugh when I go back and watch the FOX dialed videos from a few years back. At one point Jordy said that MTB has no need for coil suspension. And at that time 90% of the DH field was on air shocks. Now... I feel its the other way around.
So as suspension tech evolves, and as others said, the MTB "we have always done it this way" fades away.. I think we will see the suspension tech drift closer to more damped set ups. (USD forks that are also coil)
Side note. Its also interesting to compare MTB geo to moto geo. Same pattern is emerging. The moto started with longer reach and wide bars to get "leverage and stability" But this was all due to suspension limitations (ie the short travel, double shocks and short swing arms) Then watch as the suspension changes, so does the geo. We see wheel base grow, the swing arms (chain stays) grow, and the reach seems to fall back while the stack comes up. IMHO I think we are currently stuck somewhere in the mid 80s of moto tech and geo. USD's with full coils are coming, as are longer chain stays and more balanced frame GEOs.
Again, my opinion and there are lots of variables at play. Motor vs pedaling efficiency, terrain, etc etc.
My V1 Era started creaking after 1 summer and was warrantied. First set of V2 lowers got super sloppy in like a month. Nobody is immune to issues. I ride pretty hard but only weigh 155lbs.
I’ll probably jinx myself but my e-bike came with one of the big 1.8” CSU Zebs and after 2 seasons of smashing steep laps on that 56lb beast it’s still quiet.
Would it work to test bushing sizing by only having one stanchion inserted at a time? It seems like if the resistance you feel is higher when fully assembled is higher than with a single stanchion, the issue is with alignment. Or are there other factors that would influence that?
That is true, sometimes spacing the hub 0.15mm wider is all it takes to get the stanchions to drop in the lowers. I worked at DSD for a few years and pulled many forks apart for chassis/bushing "adjustment". Fox is far and away the worse, I'd say 90% had some degree of binding. For RS it was more like 30-40%.
The Fox floating axle system seems to have issues with the axle bore alignment between legs. They will be fine until you tighten the pinch bolt, then it binds. Hard one to fix as well as it seems to be a twist you have to correct and not a splay as is typical.
Next time you do a lower leg service; pull out the old seals, clean the lowers really well, pull the air spring & damper, put a front wheel in the lowers and drop the stanchions. The result can be shocking. 💩
Yep, you can check the actual bushing fit individually, but it is rarely that bad. It's the chassis alignment that causes the majority of the binding.
Opening up the bushings by burnishing can help, but it isn't solving the real problem.
All RS forks I've tried had no mid stroke spring support, too fast HSR when setting the LSR to my liking. All fox forks were harsh. That's boxxer 35, zeb, fox36, 38gen1. Not tried the newest from the big 2 yet. But the ohlins forks have been bang on fresh out of box within clicker adjustable range
Ha, fun reading!
Great stuff people are talking and DSD is showing these issues in MTB space.
Watching PeakTorque, Hambini and MapdecCycles videos on YT this isn't surprising at all.
Bike manufacturers inability to adhere to dimensional tolerances and QC their products is the sole reason press fit bottom brackets were so hated. Hell, I don't even think most product managers in the industry know what dimensional tolerance is. Make people overwhelm with features, shiny stuff, grams, compliance and stiffness claims, and them sell them shit so OFF, it negates any of the mentioned advantages.
From my own garage:
- painted bearing landings
- painted and wonky brake mounts
- misaligned BB
- headset bearings clunking around
- bearings eating themselves alive from misalignment
- bearings eating themselves alive from from residing in a tight hole
- rear dropouts misaligned, ones so wide apart the wheel cannot rest in them
- broken freehub pawls on a first ride
From my part time mechanic job:
- endless creak chasing with customers
- gluing in bearings so they dont move about causing creaks or simply fall out
- non stop stream of misaligned brake mounts, resulting in little to no pad clearance
I have had it... My next bikes both Gravel and MTB will be basic frames made by small/custom manufacturer who has the tools and expertise to finish up the frame. Suspension can be used to save cash and sent straight to someone who can unfuck-it like DSD.
And you didn't even work in the industry, you would have been socked. I did, I get fired 🙂
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