Can a Pedal Kickback Denier See the Light? 94

Is “pedal kickback” a thing? And what does an “active spider” actually do? In the past few years, Ochain has seen widespread adoption across the World Cup circuit, notching DH and enduro wins under the likes of Reece, Rach, Troy, Vali, Jack, Richie, Charlie, Amaury, and more. Even if you didn’t know how it worked, it seemed to be working.

Pedal kickback is the new hot topic in mountain biking, with opinions and products swirling around but not a lot of certainty as to what’s actually going on in the back of our bikes. For a long time, I was in the camp that said pedal kickback (as it’s typically understood) isn’t a thing. Yes, I’d ridden bikes without chains and felt the chainless magic, but that doesn’t automatically mean “pedal kickback” from the rear hub was the cause. Before this test, my hunch was that rear center growth and chain tension had an effect on suspension, but I didn't think that effect had anything to do with the freehub engaging. I suspect the factory World Cup teams have all done similar tests to this one in secret, and I’d personally heard enough feedback from people I trusted to be curious about Ochain. I was convinced that devices like the Ochain worked, somehow, by doing something, but I’d never seen good evidence as to how or heard a convincing explanation as to why. 

Leading pedal kickback theories include:

• “It’s the hub”
• “It’s the derailleur clutch”
• “It’s the chain”
• “I don’t know for sure, but it’s definitely a thing”

The gang at Vital agreed it was time for a test. We contacted Ochain, kindly received a 2023 Ochain R adjustable active spider to test, and Spomer flew down to film a test with slow-motion cameras on the nastiest, chunkiest rock trail we could find. And it turns out I was wrong. Pedal kickback is a thing, the rear hub plays a role, and the Ochain active spider works exactly as advertised. I need to eat a big fat hat, and there are lots of exciting implications for racing and product development.

Ochain R Adjustable Active Spider Specs

• Adjustable travel 0-4-6-9-12 degrees
• 150 grams
• +3mm virtual chainring offset for 52mm chainlines, with +3mm / +4,5mm chainline kits for 55 & 56.5mm chainlines
• Available for all major crank manufacturers and e-bike motors
• Uses BCD 104 mm chainrings, ranging from 32t to 36t
• 120kg max rider weight
• €385.00 /$420 USD

Our Plan For The Test

Our test: 23 back-to-back runs on 100 vertical feet of the steepest and rockiest section on Laguna Beach’s “Stairsteps” trail, with various bike setups to test different theories of pedal kickback. My bike for the test was a battle-tested 2020 Santa Cruz Megatower, a bike with higher-than-average levels of user-reported pedal feedback. Our test track featured a very steep section that required braking over large impacts, followed by a flatter, higher-speed section with similarly violent impacts that didn’t require any braking. This allowed us to isolate variables from the bike and trail and test those variables back-to-back. I performed multiple runs with each setup, switching back and forth between setups at times. According to my GPS, speeds on the test track topped out at 26.8 mph. 

1. Test #1: Normal Drivetrain. This was our control setting or “baseline,” with a traditional chainring and spider, chain on and derailleur clutch engaged on my Shimano XT 12-speed drivetrain, and an 8.18-degree engagement Stan’s E-Sync rear hub. I have a lot of experience with a normal drivetrain because, other than a few brief and unscheduled chainless experiences, this is how I’ve ridden bikes my entire life.
2. Test #2: Pawls Removed From Freehub. This allowed us to test the classic explanation of pedal kickback, which says that sharp impacts create spikes in chain tension that cause the freehub to rotate faster than the wheel is spinning. According to the theory, this rotational acceleration engages the freehub and sends a jarring impact through the chain to your feet. Our plan to test this theory was to remove the pawls from my freehub, removing the freehub from the equation. My hypothesis going into the test was that removing the pawls wouldn’t change anything. My rear wheel was spinning very fast on the test section, so I simply couldn’t believe the impacts could rotate the cassette faster than the wheel was spinning.
3. Test #3: Ochain. According to Ochain’s claims, the active spider works in two ways. First, by removing the effects of the engaging freehub (outlined above). Second, by allowing the chainring to float, the chain is able to grow simultaneously on the top and bottom of the drivetrain as the rear center length increases, instead of only growing from the rear derailleur taking up slack on the bottom of the drivetrain. If I was right about Test #2, and taking the pawls out of the hub didn’t make a difference, then any perceived effects from the Ochain would be a result of just the second claim. If I was wrong, and going pawl-less did impact suspension feel, then it would also be interesting to see if the pawl-less feeling was improved or enhanced by installing Ochain. As a new Ochain user, there was also the chance that Ochain didn’t do anything. I left the adjustment knob in the 12-degree position for the duration of the test, the highest setting, to maximize float and make any of the spider’s effects more pronounced.
4. Test #4: No Chain. Anyone who’s ever ridden without a chain already knows there’s something magical about the ride quality. Famously, Aaron Gwin’s 2015 chainless win in Leogang restarted the once-dead anti-squat/pedal kickback debate. For this test, comparing a chainless bike in back-to-back runs with the setups and adaptations listed above allowed us to directly compare the effects of the chain with other pedal kickback theories and to learn more about how the magic works. 

Results & Impressions from the Test

TL:DR; I was wrong. Pedal kickback is definitely a thing, and it starts at the rear hub. Incredibly, rear wheel impacts can be fast and violent enough to move the cassette faster than the spinning freehub. It’s important to note that I wasn’t seeking a new feeling from my bike in this test, as much as seeking the absence of a familiar feeling. And that’s exactly what I felt. Once I pulled the pawls out, I experienced the near-total absence of a certain bandwidth of high-frequency, stuttery, low-grade impacts that have been my constant companion in mountain biking over the last two decades. I learned that, even if you can’t hear or feel the cassette engaging when you hit bumps, that doesn’t mean it isn’t. The absence of that sensation was odd, and I had to adjust my riding technique as a result. 

I was wrong.

In our test, the effects were noticeable when coasting at all trail speeds, but especially on low to medium-speed sections, and when braking, cornering, or in situations where multiple force vectors were occurring at the same time. The effects of removing the pawls or installing the Ochain were less noticeable at higher speeds and when I wasn’t braking. Testing the bike with no chain felt better, pretty much everywhere on the trail. Chainless was noticeably "quieter," both in terms of actual noise in my ears and feedback through my feet. I also noticed that, with the high-frequency chatter muted, my rear suspension felt softer, almost like my rear tire was low, with my bike riding deeper in the travel over bumps. Some riders may need to change spring rates after installing Ochain. 

After a year on the Ochain, it definitely makes a difference, but I wouldn't say it's a total game-changer. Trails with high-frequency impacts and lots of rear wheel braking, especially where skidding is involved, are the situations where the active spider shines. I think it'll have a bigger impact for riders whose terrain is rough, rocky, sharp, or skiddy, like chairlift riding in the Alps, chunkier parts of the East Coast, racing on a World Cup track, or in Southern California where I live. Most of the downhill trails I grew up riding in Oregon had long sections of smooth dirt followed by brief sections of roots, and Ochain’s effects will be less noticeable on trails like this, or on smoother, flatter, or grippier trails, like those in a place like Boise or Bend. 

That's alotta Stairsteps.

Did the 12 degrees of float ever bother me? Not really. I got used to it immediately and could see myself happily riding the Ochain for DH, Enduro, or any sort of chairlift riding. The only time the float was noticeable was in more trials-like situations on trail, where I'd have to come to a complete stop, pause or reset, and start pedaling again. Surprisingly, I never noticed the float when I was climbing big hills, and I actually learned something interesting about technical climbing from this long-term test: I pretty much never stop pedaling when I’m climbing a big hill. The entire time I’m going uphill, even when I vary speed or get out of the saddle to charge up a section, I’m still spinning the cranks and always have force pushing back on my feet. One particular instance where I do remember feeling the crankarms floating under my feet was on the technical crux moves of the classic XC trail “Skyline” above Big Bear Lake, California. Those were moves that required me to come to a complete stop, reposition the bike, and then start pedaling again. I cleaned a few of these sections and I missed a few, and the crankarm float was annoying in those situations. However, I don’t think removing the Ochain would have instantly resulted in me batting a thousand. I'm not Hans Rey, so I think I would have missed a couple of those crux moves anyway.

Durability

After a full year of riding the Ochain on two different bikes in California, Oregon, Washington, and Idaho, the durability has been acceptable. The device was quiet and issue-free for most of the year, including lots of chairlifts, rain, and mud. The decline in health came after a week of riding the muddy Oregon trails I grew up on over a particularly wet Christmas break. I didn’t have any issues while I was in Oregon, but the spider quickly started creaking and then developed play after the trip. Some users have reported similarly fast deterioration in wet climates. If you live in the PNW, Coastal BC, the UK, or somewhere equally wet and sloppy, take that into consideration, and make sure to clean things off inside the spider after a particularly wet and muddy ride and make sure the device is fully sealed. Ochain recommends inspecting the spider for needed maintenance if you hear or see anything unusual, and sells repair kits for well-worn units. After a year of abuse and neglect, the spider finally came loose on a shuttle day riding the Telonics trail in Laguna. It started developing a small amount of play inside the spider, but I kept riding out of a mix of curiosity, dedication to thorough testing, and laziness. There was enough play that I ended up wearing off some of the anodizing on the backside of the spider, pictured above. Whoops! If your Ochain starts creaking, I'd recommend servicing it.

I also didn’t love the aluminum chainring bolts, and broke one during the test. Is that my fault for over-torquing it? Probably. I wasn’t using a torque wrench when it broke. On the other hand, have I ever broken a steel chainring bolt, with or without a torque wrench? Absolutely not. Just like you’re not going to see me saving grams with alloy spokes nipples, I’d always prefer stainless chainring bolts.

Because of the shape of the spider and the proprietary chainring bolts Ochain uses, the spider won't be compatible with all 104 BCD chainrings. Pictured here with a Dremel-modified Shimano 34 tooth ring, mounted backwards to fit.

Another consideration is the cost, at over $400 US. Is it worth it? That all depends. If I were still racing DH and Enduro full-time, I wouldn't show up to a race without it. For beginners, the subtle improvement from Ochain is definitely not worth the money or hassle, as it’s another component that will demand time, attention, and maintenance. For everyone else that's somewhere between beginner and pro, it’s up to you to decide how to spend your fun tokens. I imagine Ochain will be especially enticing for flat pedal riders, dedicated downhill bikes, or riders with frames that have higher-than-average amounts of chain growth or anti-squat.

I was testing the 2023 version of the Ochain R active spider, with an externally adjustable float setting with options for 4, 6, 9, and 12 degrees of float. The newest version of the Active R features all the same float settings and a new zero-degree setting, which I think is perfect. With a zero-degree option, there’s almost no reason not to run one, because you can switch from "bike park" mode to "trail bike" mode without swapping chainrings.

Room for Additional Research

While this test was helpful, it raises as many questions as it answers. Some areas for additional research include:

• The new E.thirteen Sidekick Hub (currently in the test queue)
• STFU bike chain slap devices to isolate chainslap effects. Link to video
• The Williams Racing Products Centrehub
• Timed runs instead of subjective feedback
• Blind testing to eliminate the placebo effect and user bias
• The effect of low vs. high engagement hubs?
• Data acquisition to measure suspension and braking
• Lastly, measuring freehub speed could help quantify when and how often the freehub is engaging from rear wheel impacts

Conclusion

I’m really impressed with the Ochain Active Spider R. It made my bike quieter, smoother, and faster. Mostly, I was surprised to be so wrong about pedal kickback. It’s a real thing, it starts at the rear hub, and I’ll be eating my hat. In a crowded MTB market where a lot of other technologies have plateaued, pedal kickback is an exciting area for continued research and potential gains in suspension performance. Additionally, there are some other products on the market that are worth checking out, like STFU Bike and the soon-to-be-released e.thirteen Sidekick hub. Do you need to worry about pedal kickback on your bike? Probably not. Worrying about this topic is strictly optional, and the Ochain is another in a long list of expensive components that will require care and maintenance, like a suspension fork or disk brakes. But if you’re a serious racer or serious nerd, the Ochain Active Spider is a great, innovative product that does exactly what’s advertised. Real innovation is pretty cool, and it’s a great time to ride mountain bikes.