Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the...
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the light compression code for Fox similar to the c26 compression code and so on. Be curious on where each of the companies "tunes" land in comparison to each other.
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these forums (can't remember which) about the new standardized RS tuning nomenclature, which makes a lot of sense. It used to me L, M, or H, but sometimes the H was actually softer than the M, etc etc and oftentimes employees deep inside RS couldn't remember when tunes were created, how much damping force they generated, and more. Now it's linear and standardized, so 31 is always more damping than 27, and so on, and those tunes are transferable across platforms, like a Vivid to a SDLX. My understanding for Fox is that they're still using a L/M/H tune system akin to the old RS system, which does not translate neatly across platforms.
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the...
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the light compression code for Fox similar to the c26 compression code and so on. Be curious on where each of the companies "tunes" land in comparison to each other.
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these...
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these forums (can't remember which) about the new standardized RS tuning nomenclature, which makes a lot of sense. It used to me L, M, or H, but sometimes the H was actually softer than the M, etc etc and oftentimes employees deep inside RS couldn't remember when tunes were created, how much damping force they generated, and more. Now it's linear and standardized, so 31 is always more damping than 27, and so on, and those tunes are transferable across platforms, like a Vivid to a SDLX. My understanding for Fox is that they're still using a L/M/H tune system akin to the old RS system, which does not translate neatly across platforms.
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a few folks I know looking to jump ship from X2s to Vivids and I wanted to see if I could help them figure out a decent base tune based on Fox's L/M/H to RS's numbers between Vivid and X2.
Also, I guess when we are down the path of talking about shock tuning. When have folks decided that a re-shim is needed vs just fiddling with the adjusters. I know a shimstack creates the shape of the force curve and the adjusters are more just moving that shape around, but when is it worth changing the stack vs adjusters. I know there's probably a lot of "tuner magic" that goes into answering that question, I'm more just curious on what people are willing to share on this process.
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the...
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the light compression code for Fox similar to the c26 compression code and so on. Be curious on where each of the companies "tunes" land in comparison to each other.
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these...
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these forums (can't remember which) about the new standardized RS tuning nomenclature, which makes a lot of sense. It used to me L, M, or H, but sometimes the H was actually softer than the M, etc etc and oftentimes employees deep inside RS couldn't remember when tunes were created, how much damping force they generated, and more. Now it's linear and standardized, so 31 is always more damping than 27, and so on, and those tunes are transferable across platforms, like a Vivid to a SDLX. My understanding for Fox is that they're still using a L/M/H tune system akin to the old RS system, which does not translate neatly across platforms.
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a...
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a few folks I know looking to jump ship from X2s to Vivids and I wanted to see if I could help them figure out a decent base tune based on Fox's L/M/H to RS's numbers between Vivid and X2.
Also, I guess when we are down the path of talking about shock tuning. When have folks decided that a re-shim is needed vs just fiddling with the adjusters. I know a shimstack creates the shape of the force curve and the adjusters are more just moving that shape around, but when is it worth changing the stack vs adjusters. I know there's probably a lot of "tuner magic" that goes into answering that question, I'm more just curious on what people are willing to share on this process.
A lot of it is due to rider ability and preference and existing bike setup (i.e native tune of the shock).
In my opinion, broadly speaking a fast rider on a 140+ bike that likes moderate to high damping (and you should) will benefit from re-tuning a shock to a firmer overall settings.
As on Rockshox and more to the point fox products, most fast riders are close to maximising the usable damping range before they hit a LSC wall and can't reallt use the end range of clicks without it losing early travel grip and responsiveness.
Its why so many people love Ohlins and it's a totally different feeling, it's just much more damping overall than the standard RS and fox tunes.
Having said that, 2 times a week strength training will yield more benefits in speed than a custom $1000 shock anyway, so take away what you will.
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the...
Thanks again for everyone's help! For those who have tested things in dyno, is there any correlation to Fox's tune codes to RockShocks? E.g is the light compression code for Fox similar to the c26 compression code and so on. Be curious on where each of the companies "tunes" land in comparison to each other.
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these...
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these forums (can't remember which) about the new standardized RS tuning nomenclature, which makes a lot of sense. It used to me L, M, or H, but sometimes the H was actually softer than the M, etc etc and oftentimes employees deep inside RS couldn't remember when tunes were created, how much damping force they generated, and more. Now it's linear and standardized, so 31 is always more damping than 27, and so on, and those tunes are transferable across platforms, like a Vivid to a SDLX. My understanding for Fox is that they're still using a L/M/H tune system akin to the old RS system, which does not translate neatly across platforms.
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a...
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a few folks I know looking to jump ship from X2s to Vivids and I wanted to see if I could help them figure out a decent base tune based on Fox's L/M/H to RS's numbers between Vivid and X2.
Also, I guess when we are down the path of talking about shock tuning. When have folks decided that a re-shim is needed vs just fiddling with the adjusters. I know a shimstack creates the shape of the force curve and the adjusters are more just moving that shape around, but when is it worth changing the stack vs adjusters. I know there's probably a lot of "tuner magic" that goes into answering that question, I'm more just curious on what people are willing to share on this process.
I don't have full sweeps of the latest tunes from Fox and Rockshox but this plot is a rough approximation of where the tunes sit - generally there isn't really a nice match between the 2 brands, Fox shocks also vary wildly from year to year and each models also has very different characteristics. Rockshox has had fairly similar damping profiles (at least on compression) since the super deluxe launched, and even the Monarch Plus wasn't too different. They were slightly digressive, with the adjuster mostly changing the overall force but the newer 2025 shocks seem to be more linear with a lower threshold at low speeds. As seen comparing the super deluxe C40 tune with the vivid C30 - the SDLX has a steeper gradient and more high speed damping but significantly softer at low speed. Although its not on here, most of the tunes from the 2021 Float X2 would have been firmer than all of these, even fully open. The "C" labelled super deluxe tunes (opposed to L, M, H) are all using the new piston
Adjuster range and function is super important when comparing tunes - each brands "low speed" and "high speed" dial can have more or less affect on the entire range of speeds, as well as more or less resolution between each click. So most shocks have a sweet spot in the range they work best while others are pretty useful for different people across the whole range. So I would normally compare tunes at specific points people would use (as opposed to just middle, open or closed) but these tests were mostly run separate so aren't designed to match. The closest match though would be between the current Float X2 "CX2" tune to the Rockshox Super Deluxe C40 which is interesting because CX2 is the second softest tune while C40 is the stiffest for RS.
Also the Rockshox settings are the absolute position from fully closed (as is the convention for literally everybody) and not the +/- labelled on the adjuster which is confusing as heck. Therefore -2 is the middle and -4 is fully open
*final note: please don't use this plot to infer anything other than what I've tried to quickly explain here - they are standard "PVP" plots which give an overall impression of the damping rates but there are a lot of layers to comparing damping including adjuster range, spring design and hysteresis, so even 2 shocks that look quite similar will have a very different feel on the trail
Oh yeah I also mean to talk about adjusters vs reshimming - you should always exhaust the full range of the adjusters you have first, which comes after bracketing your spring rates/air pressures. A lot of people get led down the wrong path of making some assumption with spring rate and volume spacers (ie soft spring + too many tokens or vise versa) so if its too soft they will never get the damper rebounding fast enough and think they need a faster rebound tune, or maybe stiffer compression tune. Where if the spring was set better you might not need to touch the damper, or even go completely the opposite direction. But usually I would work through a kind of flow chart, finding the upper and lower limit of spring pressure, then volume spacers and if you reach a point that the air spring is as high as you can manage while having OK grip, but the support is lacking then try closing the compression and if that improves support (but reduces grip) then its a good sign the high speed tune should be stiffer. With rebound, I would make sure spring and compression are good first, then run through the range of rebound adjustment - if you need it to be right at the extremes then its time to change. Deciding if you need softer compression is maybe harder to describe - if the spring is too soft it can feel very harsh but not necessarily bottom out, so again I would make sure your spring rate has been throughly bracketed and then bracket the full range of compression damping. If fully open feels the best then you can probably go with a retune.
I always come back to bracketing because people often don't realise how much higher in pressure they can go - a bike can still be "functional" at 40psi or more below the ideal setting, but if they add 20psi and it feels better they just assume thats as good as it gets because it was such a big step. You really need to keep going up to find the point where it starts getting worse, and then come back a little from there.
I've always wanted to play around with the ReSacker program for shimming. Every time I do though I get confused and aggregated. I believe once you...
I've always wanted to play around with the ReSacker program for shimming. Every time I do though I get confused and aggregated. I believe once you figured out that program it could be really useful.
It's not. The results arent even close to the real world but even in you spend hours getting perfect measurements of your damper it still doesn't...
It's not. The results arent even close to the real world but even in you spend hours getting perfect measurements of your damper it still doesn't give you anything useful. It promotes itself as replacing a dyno but it really isn't, you are better off with trial and error as restackor will just confuse you. You would think it might be useful to iterate shim stacks before dyno testing them but it isn't, I'm pretty sure it would be cheaper and easier to teach yourself CAD and CFD with some of the free and open source software tools out there instead. I don't know anyone who uses it once they own an actual dyno
Maybe play with the free version to get an idea of how things work but definitely take it with a grain of salt
I've only played around with the free version, initially by plugging in my existing LSC shim-stack and then aiming for something stiffer.
Most recently, I asked chatGPT for a (stiffer than what I put in) shim-stack recommendation. I then used restackor to confirm and adjust to confirm a stiffer shim stack.
Full disclosure:
I have no skin in this game, I just like tinkering/messing around with suspension (Diy runt, piston mods, coil conversions). But I must say, my fork is definitely better because of the shim-stack mods.
I have been playing with the stock RUNT +10mm extended piston. I bored it out and was able to increase the internal volume by close to 10% with the goal being to reduce the progression. I also swapped out the o-ring for a quad ring and a few other things.
Seems to be working well, improvement over stock for sure.
I think Chickadeehill has this style of floating piston?
One possible reason is to have more volume at full compression in the secondary chamber but drill being able to assemble the whole assembly in the given length.
That was the idea, increase volume for less progression near bottom out.
I have a Chickadeehill in a Boxxer. It is a well thought out version of a second positive air chamber system. Modular design, very light weight, the piston is bored out and it uses a quad ring to seal. For sure German....😉
Nice!What do you have going on with the piston?I have been playing with the stock RUNT +10mm extended piston. I bored it out and was able...
Nice!
What do you have going on with the piston?
I have been playing with the stock RUNT +10mm extended piston. I bored it out and was able to increase the internal volume by close to 10% with the goal being to reduce the progression. I also swapped out the o-ring for a quad ring and a few other things.
Seems to be working well, improvement over stock for sure.
Similar set-up with a hole drilled in the bottom for exta volume. I went with 2 o-rings so stop any chance of the piston cocking in the bore. The second o-ring doesn't do any sealing, it is just a guide.
I also trialled a piston with double u-cup seals. But I tested the breakaway force needed to get it moving and it was not as good as the 2 o-ring setup.
As much as I like the Telum and the clamp shim adjustment, I don't think it can match performance and tunability of a custom shim stack. IMO a properly tuned Avy will still come with fever performance trade-offs than a properly set up Telum.
As much as I like the Telum and the clamp shim adjustment, I don't think it can match performance and tunability of a custom shim stack...
As much as I like the Telum and the clamp shim adjustment, I don't think it can match performance and tunability of a custom shim stack. IMO a properly tuned Avy will still come with fever performance trade-offs than a properly set up Telum.
Actually, my time spent on a Telum is kinda what prompted this whole can of worms in my life, and I think to Vorsprungs credit, they pretty much nail it.
here comes complete speculation, I could be probably way off
As far as I've been able to understand, when it comes to a shim stack, pretty much every shim past the main face shim is to help control the flex of the face shim, basically customizing the flex property of that shim to respond in set ways during load. So in that respect, any sort of of system that directly changes the flex of the shim is equivalent to "re-stacking" a shim stack. That's what VVC was attempting to do, and thats what the Telum does. The Telum does this by actually making contact with the shim in a set way depending on the amount of turns set on a worm screw. Which means its less prone to the tolerance issues that the VVC had (and, because its physically touching) probably acts even more like a re-shim.
I'll conceded that there is probably a touch less "fidelity" in the Telum system than maybe a custom shim stack, but If I were a betting man, I'd say that Vorsprung would probably argue that the "next level" of customization in damper curves using complex shim stacks could provide are just not useful for the mountain bike application (or at least not as useful as the breath of tune curves the telum can produce with its setup). And frankly, damper forces on a mountain bike are probably not nearly as high as they are in other applications because there just isn't the raw sprung and unsprung mass.
Mountain bike shocks are fairly unique actually because of the breadth of damping they need to do - they need to handle fairly high speed hits in high speed compression events (nothing too dramatic), but at the same time the low speed performance (platforms, bobbing prevention, etc.) is much farther away from the high speed stuff than most other applications. Or at least the shock is the only thing handling that. With cars for example you have the sway bars to handle side to side low speed suspension events.
Short answer, I don't think it's a neat translation from Fox tunes to RS or vice versa. There was a great discussion in one of these forums (can't remember which) about the new standardized RS tuning nomenclature, which makes a lot of sense. It used to me L, M, or H, but sometimes the H was actually softer than the M, etc etc and oftentimes employees deep inside RS couldn't remember when tunes were created, how much damping force they generated, and more. Now it's linear and standardized, so 31 is always more damping than 27, and so on, and those tunes are transferable across platforms, like a Vivid to a SDLX. My understanding for Fox is that they're still using a L/M/H tune system akin to the old RS system, which does not translate neatly across platforms.
Yeah, I remember reading that, I think @Dave_Camp was the one who was commenting on the RS nomenclature being consistent throughout the shocks. I have a few folks I know looking to jump ship from X2s to Vivids and I wanted to see if I could help them figure out a decent base tune based on Fox's L/M/H to RS's numbers between Vivid and X2.
Also, I guess when we are down the path of talking about shock tuning. When have folks decided that a re-shim is needed vs just fiddling with the adjusters. I know a shimstack creates the shape of the force curve and the adjusters are more just moving that shape around, but when is it worth changing the stack vs adjusters. I know there's probably a lot of "tuner magic" that goes into answering that question, I'm more just curious on what people are willing to share on this process.
A lot of it is due to rider ability and preference and existing bike setup (i.e native tune of the shock).
In my opinion, broadly speaking a fast rider on a 140+ bike that likes moderate to high damping (and you should) will benefit from re-tuning a shock to a firmer overall settings.
As on Rockshox and more to the point fox products, most fast riders are close to maximising the usable damping range before they hit a LSC wall and can't reallt use the end range of clicks without it losing early travel grip and responsiveness.
Its why so many people love Ohlins and it's a totally different feeling, it's just much more damping overall than the standard RS and fox tunes.
Having said that, 2 times a week strength training will yield more benefits in speed than a custom $1000 shock anyway, so take away what you will.
I don't have full sweeps of the latest tunes from Fox and Rockshox but this plot is a rough approximation of where the tunes sit - generally there isn't really a nice match between the 2 brands, Fox shocks also vary wildly from year to year and each models also has very different characteristics. Rockshox has had fairly similar damping profiles (at least on compression) since the super deluxe launched, and even the Monarch Plus wasn't too different. They were slightly digressive, with the adjuster mostly changing the overall force but the newer 2025 shocks seem to be more linear with a lower threshold at low speeds. As seen comparing the super deluxe C40 tune with the vivid C30 - the SDLX has a steeper gradient and more high speed damping but significantly softer at low speed. Although its not on here, most of the tunes from the 2021 Float X2 would have been firmer than all of these, even fully open. The "C" labelled super deluxe tunes (opposed to L, M, H) are all using the new piston
Adjuster range and function is super important when comparing tunes - each brands "low speed" and "high speed" dial can have more or less affect on the entire range of speeds, as well as more or less resolution between each click. So most shocks have a sweet spot in the range they work best while others are pretty useful for different people across the whole range. So I would normally compare tunes at specific points people would use (as opposed to just middle, open or closed) but these tests were mostly run separate so aren't designed to match. The closest match though would be between the current Float X2 "CX2" tune to the Rockshox Super Deluxe C40 which is interesting because CX2 is the second softest tune while C40 is the stiffest for RS.
Also the Rockshox settings are the absolute position from fully closed (as is the convention for literally everybody) and not the +/- labelled on the adjuster which is confusing as heck. Therefore -2 is the middle and -4 is fully open
*final note: please don't use this plot to infer anything other than what I've tried to quickly explain here - they are standard "PVP" plots which give an overall impression of the damping rates but there are a lot of layers to comparing damping including adjuster range, spring design and hysteresis, so even 2 shocks that look quite similar will have a very different feel on the trail
Oh yeah I also mean to talk about adjusters vs reshimming - you should always exhaust the full range of the adjusters you have first, which comes after bracketing your spring rates/air pressures. A lot of people get led down the wrong path of making some assumption with spring rate and volume spacers (ie soft spring + too many tokens or vise versa) so if its too soft they will never get the damper rebounding fast enough and think they need a faster rebound tune, or maybe stiffer compression tune. Where if the spring was set better you might not need to touch the damper, or even go completely the opposite direction. But usually I would work through a kind of flow chart, finding the upper and lower limit of spring pressure, then volume spacers and if you reach a point that the air spring is as high as you can manage while having OK grip, but the support is lacking then try closing the compression and if that improves support (but reduces grip) then its a good sign the high speed tune should be stiffer. With rebound, I would make sure spring and compression are good first, then run through the range of rebound adjustment - if you need it to be right at the extremes then its time to change. Deciding if you need softer compression is maybe harder to describe - if the spring is too soft it can feel very harsh but not necessarily bottom out, so again I would make sure your spring rate has been throughly bracketed and then bracket the full range of compression damping. If fully open feels the best then you can probably go with a retune.
I always come back to bracketing because people often don't realise how much higher in pressure they can go - a bike can still be "functional" at 40psi or more below the ideal setting, but if they add 20psi and it feels better they just assume thats as good as it gets because it was such a big step. You really need to keep going up to find the point where it starts getting worse, and then come back a little from there.
I've only played around with the free version, initially by plugging in my existing LSC shim-stack and then aiming for something stiffer.
Most recently, I asked chatGPT for a (stiffer than what I put in) shim-stack recommendation. I then used restackor to confirm and adjust to confirm a stiffer shim stack.
Full disclosure:
I have no skin in this game, I just like tinkering/messing around with suspension (Diy runt, piston mods, coil conversions). But I must say, my fork is definitely better because of the shim-stack mods.
DIY runt?
Nice!
What do you have going on with the piston?
I have been playing with the stock RUNT +10mm extended piston. I bored it out and was able to increase the internal volume by close to 10% with the goal being to reduce the progression. I also swapped out the o-ring for a quad ring and a few other things.
Seems to be working well, improvement over stock for sure.
I think Chickadeehill has this style of floating piston?
One possible reason is to have more volume at full compression in the secondary chamber but drill being able to assemble the whole assembly in the given length.
That was the idea, increase volume for less progression near bottom out.
I have a Chickadeehill in a Boxxer. It is a well thought out version of a second positive air chamber system. Modular design, very light weight, the piston is bored out and it uses a quad ring to seal. For sure German....😉
Similar set-up with a hole drilled in the bottom for exta volume. I went with 2 o-rings so stop any chance of the piston cocking in the bore. The second o-ring doesn't do any sealing, it is just a guide.
I also trialled a piston with double u-cup seals. But I tested the breakaway force needed to get it moving and it was not as good as the 2 o-ring setup.
The Vorsprung Telum needs some mention here. The fact that you can change the tune it in 5 minutes w/o a rebuild is amazing.
Externally adjustable clamp shim diameter plus a massive tuning database will forever change the suspension game, no more hand jobs for @TEAMROBOT
https://www.youtube.com/watch?v=C5RomAga7qs&t=38s&ab_channel=VorsprungSuspension
https://www.youtube.com/watch?v=xx5-vHt-mVo&t=235s&ab_channel=VorsprungSuspension
As much as I like the Telum and the clamp shim adjustment, I don't think it can match performance and tunability of a custom shim stack. IMO a properly tuned Avy will still come with fever performance trade-offs than a properly set up Telum.
Actually, my time spent on a Telum is kinda what prompted this whole can of worms in my life, and I think to Vorsprungs credit, they pretty much nail it.
here comes complete speculation, I could be probably way off
As far as I've been able to understand, when it comes to a shim stack, pretty much every shim past the main face shim is to help control the flex of the face shim, basically customizing the flex property of that shim to respond in set ways during load. So in that respect, any sort of of system that directly changes the flex of the shim is equivalent to "re-stacking" a shim stack. That's what VVC was attempting to do, and thats what the Telum does. The Telum does this by actually making contact with the shim in a set way depending on the amount of turns set on a worm screw. Which means its less prone to the tolerance issues that the VVC had (and, because its physically touching) probably acts even more like a re-shim.
I'll conceded that there is probably a touch less "fidelity" in the Telum system than maybe a custom shim stack, but If I were a betting man, I'd say that Vorsprung would probably argue that the "next level" of customization in damper curves using complex shim stacks could provide are just not useful for the mountain bike application (or at least not as useful as the breath of tune curves the telum can produce with its setup). And frankly, damper forces on a mountain bike are probably not nearly as high as they are in other applications because there just isn't the raw sprung and unsprung mass.
Mountain bike shocks are fairly unique actually because of the breadth of damping they need to do - they need to handle fairly high speed hits in high speed compression events (nothing too dramatic), but at the same time the low speed performance (platforms, bobbing prevention, etc.) is much farther away from the high speed stuff than most other applications. Or at least the shock is the only thing handling that. With cars for example you have the sway bars to handle side to side low speed suspension events.
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