Review: O-Chain's Active Spider Adds Suppleness & Silence
Mountain bike drivetrains have evolved from sounding like a bucket of bolts rattling down the trail to something much less distracting thanks to the introduction of the clutch derailleur. In combination with narrow-wide chainrings, it's rare to drop a chain these days. In some cases, that silence and security may come at the cost of suspension suppleness due to the tension in the derailleur, especially on bikes with high anti-squat values that tend to have more perceived pedal kickback.
O-chain’s Active MTB Spider is essentially a chain damping system that claims to “release rear suspension” from the transmission. It does so by adding a floating element between the chainring and crankarm for either traditional bikes or eMTBs. Adding another component or level of complexity might seem like over-engineering, but the Active Spider stands to overcome what the clutch derailleur has undone, all in the name of suspension performance while still producing a stealthy ride.
O-chain’s Active MTB Spider is essentially a chain damping system that claims to “release rear suspension” from the transmission. It does so by adding a floating element between the chainring and crankarm for either traditional bikes or eMTBs. Adding another component or level of complexity might seem like over-engineering, but the Active Spider stands to overcome what the clutch derailleur has undone, all in the name of suspension performance while still producing a stealthy ride.
O-Chain Active Spider Details
• Intended use: All full-suspension bikes
• 4, 6, 9, 12 degrees of articulation
• Aluminum 7076 T6 alloy body, elastomer bumpers
• Mounting patterns: SRAM, Shimano, Race Face, Hope, FSA, E13, Cane Creek, Brose (eMTB), Bosch, Shimano EP8
• Drivetrain specs: 52mm chainline, 30-36T chainring, 104 BCD
• Titanium chainring bolts included
• Weight: 128 grams
• Max rider weight: 100kg
• MSRP: €299
• More info: ochain.bike
• Intended use: All full-suspension bikes
• 4, 6, 9, 12 degrees of articulation
• Aluminum 7076 T6 alloy body, elastomer bumpers
• Mounting patterns: SRAM, Shimano, Race Face, Hope, FSA, E13, Cane Creek, Brose (eMTB), Bosch, Shimano EP8
• Drivetrain specs: 52mm chainline, 30-36T chainring, 104 BCD
• Titanium chainring bolts included
• Weight: 128 grams
• Max rider weight: 100kg
• MSRP: €299
• More info: ochain.bike
Once installed, you can see how the Active Spider lets the chainring rotate.
Details
The inner black portion of the spider fixes to the crank arm while the nickel-colored portion makes up the back half of the spider that the chainring mounts to.
The "End Stroke" etching shows how the black component rotates through the pedal to meet the gold chip that sets the degree of float before the chain is tensioned - in this case 6 degrees. 4, 9, and 12-degree chips are also available.
The second half of the floating housing uses a 104mm bolt-circle diameter spider and fits chainrings down to a 30-tooth.
Do not nourish yourself with these garnishes. They are elastomers, not Ju Jubes.
O-Chain machines their Active Spiders in Italy and offers anodized black or nickel-chrome treatments for all popular direct mount crank/chainring interfaces from SRAM, Shimano, Race Face, Hope, FSA, E13, and Cane Creek for bikes with 52mm chainlines. Each spider is machined from an aluminum 7076 T6 alloy and is compatible with chainrings between 30 and 36 teeth. This SRAM spider weighed 128g, as claimed, without the chainring bolts. E-bikes haven’t been left out either since O-Chain has kits to work with Brose, Bosch, and Shimano EP8 motor mounts too.
The component arrives in the 6-degree setting and includes the necessary parts to change that float to 4 or 9 degrees as well. Those three settings are aimed at enduro-style riding, however, there is a larger 12-degree float option as well. O-Chain recommends this setting for downhill bikes since they have more rear wheel travel, are often subjected to higher forces and don’t require as many half-pedal, ratcheting movements that are common while climbing.
A gold-coloured metal chip is stamped with the number of degrees (in this case “6”) that the spider can rotate freely - the smaller the chip, the more the spider rotates. Elastomers matching the size of the chip are then situated to soften the rotating half of the spider as the crank engages the chainring.
This only affects the forward rotation of the crank, although there is another set of round elastomers that soften the return of the spider as it reaches the neutral position and dissipates some forces of the ring if it is rotated in the clockwise direction.
Setup
Setting up the Active Spider is as straightforward as bolting on a 4-bolt chainring and spider. I began by using the 6-degree, stock configuration and didn’t need to play with the chainline spacing at all. If you do wish to mess with the spacing, O-Chain does sell bolt kits to move the chainline either 3 or 4.5mm to either side of the spider.
Installing Active Spider on the Yeti SB160 wasn’t a hassle, but I did have to move the upper portion of the chainguide well out of the way to clear the spider as it rotated around a 32-tooth Wolf Tooth brand chainring. That’s because the spider is bulkier than a direct mount chainring. This means that the upper portion of the guide doesn’t actually sit close enough to keep the chain from lifting off of the ring. Although I never experienced any derailments, a simple post-style upper guide without captive sides might be best here.
Price
From the outside, this clever device seems simple, but there are a number of intricate pieces placed inside. At €299 the Active MTB Spider isn’t cheap, however this is a one-of-a-kind component for an attentive rider looking to optimize their suspension characteristics.
Two other important considerations are the fact that each Active Spider is brand-specific to the crank interface and you will need to use a 104 bolt-circle chainring (BCD). There is no price difference between mounting-type for the standard spiders but the eMTB is slightly more expensive at €328. O-Chain includes the titanium chainring bolts with the kit but only guarantees fitment with their own chainrings that cost €62. The 30-tooth costs 10€ more because those integrate the female end of the bolt connection.
Additional equipment, service kits and replacement parts are also available through distributors or O-Chain’s website. The 12-degree elastomer kit cost €19 and the service kits are €28.
The wax-paper seal has kept the inner workings of the spider clean and creak-free so far.
Maintenance and Warranty
Opening up the O-Chain to change the float is a bit tedious, so patience and steady hands are crucial. The color-coded elastomers are slightly curved, so it’s important to pay close attention to their orientation to avoid damaging the device. A chart depicting each auxiliary elastomer is provided and the switch doesn’t necessarily require removing the spider from the crank itself, but it does make it clumsy to handle the half with the pedal attached.
Throughout the course of the test, the O-Chain was subjected to both apocalyptic dust and buckets of rain but never produced any creaks or unwanted noise. The chainring bolts and housing hardware never wiggled loose either. Throughout the test, the system remained solid feeling underfoot and not once slipped or felt questionable.
The only component that I would question would be the thick, waxy paper seal between the housing halves. I do wonder how well that would hold up to an entire winter of grit and bike washing.
In terms of the warranty, O-Chain offers a two year guarantee for the original owner, with proof of purchase. When you do need to replace any parts from normal use, grease seal and bolts are available, plus, there’s a full rebuild kit for about 50€.
Even with the success of narrow-wide chainrings, I still advocate for top guides and skid plates on any mountain bike. There's no doubt that the O-Chain Active Spider calms down chain oscillations, but some adjustments may be needed for smaller chainrings.
A chainguide without overhanging walls, like this one, could be lowered to the optimal height for 30 and 32-tooth chainrings without contacting the spider.
Ride Impressions
O-Chain’s Active Spider theory to reduce chain forces sounds like the bee's knees on paper, but how does it operate in the real world? On my first ride, it was immediately apparent that there was magic happening under my feet, but that didn’t come without some acclimatization.
The first reaction you will have with the O-Chain is the newfound “give” that the pedal stroke has compared to a fixed spider. Surprisingly though, that lag is not as severe or abrupt as the feeling of a low-engagement hub. The soft-touch engagement that the elastomers produce is similar to a sprag clutch found on the Onyx brand of rear hubs.
On most mellow climbs a rider continues to spin the cranks in a nearly continuous motion, so the elastomer will stay compressed without any noticeable lag in the chain tension. It’s only when you stop or ease your input on the cranks do you feel that float again. The 6-degree setting never bothered me, even when I had to ratchet my way through some pinch points or hop up a step on the trail. For this reason, I never installed the 4-degree option and hoped to gain more on the descents from the larger of the two choices. Moving to the 9-degree elastomer chip is where my crank inputs took slightly more effort and attention.
I primarily spent time riding the 6-degree setting because that didn’t deter my climbing ability and the reward while descending was clear as day when the bike encountered the first set of bumps. Initially, I thought I lost pressure in the rear shock because the sensitivity of the suspension was incredible. After double-checking the shock pressure and heading out for another ride, it was apparent that the Active Spider had added a serious amount of performance to the bike.
Not only did it allow the rear suspension to move into the travel effortlessly, it also reduced movement in the chain as it oscillated down the trail. Now the Yeti SB160 was already an impressively quiet bike, but on large hits, you could still notice when the chain thumped against the rubber protector on the chainstay. That feature did its job well, but the O-Chain improved that element of damping even further.
Another bike I had the chance to briefly try the Active Spider on was Cotic’s RocketMax. Both bikes came equipped with SRAM AXS derailleurs that have been noted to produce more chainslap. That seemed like the perfect opportunity to test the capabilities of how the O-Chain system could reduce chain feedback. It shouldn't have been any surprise that the Active Spider made the ride plusher and quieter.
In terms of pedal kickback, that can be a tricky topic to dissect. What I can confidently speak to is the fact that the Active Spider brought a sense of riding downhill without a chain. This was most noticeable on repeated square edge hits, like braking bumps.
This sensation may just offer flat pedal riders more security when it comes to keeping their feet in place on the pedals. Proving that is difficult. I didn’t exactly set out to try and blow my foot off of the pedals, but without the O-Chain there is more perceived feedback through the chain and ultimately your feet.
You might ask, why do I need to spend 299€ when a hub with low engagement is less prone to pedal kick back. While the jury is still out there on the physics behind pedal kickback and the instances of when it actually occurs, those hubs don’t remove the amount the chain gets pulled by the suspension. (?) and they definitely don’t reduce the amount the chain oscillates.
Even in the 6-degree setting, which is still higher than some low-end hubs’ engagement, the benefits are very clear on the descents with minimal drawbacks while climbing. If I had the choice between riding a bike with a fixed chainring and hub with 36 teeth (that would engage every 10 degrees), or the O-Chain Active Spider in the 9-degree setting and a hub like the Industry Nine Hydra that picks up the crank input every 0.5 degrees, I’d opt for the later for its ability to isolate the chain from the suspension and provide a quieter ride.
Pros
+ Improves the compliance of the rear suspension
+ Reduces pedal kickback considerably
+ Calms down chain oscillations which leads to a quieter ride
+ Soft pedal feel is more pleasant than a low engagement hub
Cons
- Lag in chain torque makes ratcheting through technical sections feel strange at first
- Upper chain guides positioned for 30 and 32-tooth rings can contact spider
Pinkbike's Take
 | The chain forces that the Active Spider isolates is quite impressive. I believe there is both a physical improvement to the suspension performance when the chainring can rotate to a degree, plus it adds a qualitative bonus by reducing the noises caused by chainslap. The small amount of lag in the pedal stroke is a tradeoff that is worth coming to terms with if the bike in question is susceptible to chain feedback. |
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Improves compliance of your over-engineered "efficient" frame with super high anti squat
Reduces pedal kickback from your high engagement hub
Quiets chain slap from your $800 derailleur (assuming you can hear anything besides your obnoxious hub...)
It's been debated a lot on PB whether chain growth can actually occur fast enough to overspeed the rolling of the wheel and engage the hub pawls. I'm of the assumption that it cannot, and that what we actually feel in the pedals is the chain pulling on the sprocket (and pedals), simply because it is bouncing up and down..creating spikes in tension.
The bottom length of chain is damped by the cage tensioner...the top, all the force goes into the sprocket.
Under this assumption, this device would help on a hard tail as well. Although one could argue that rear wheel accelerations are less on a hardtail because it is resisted by the riders weight more.
STIMPY...YOU 1D10T!!
But the difference is that a 10° engagement hub doesn't always engage at 10°, that's just the maximum amount of movement but it could also be anything from 0-10° depending on where the pawls happen to be located in the drive ring at any given time.
This doesn't negates any kickback.
This doesn't reduce forces from clutch.
It does something else.
- Kickback
If the wheel is spinning fast enough and the cranks are still, there can't be any kickback. Because there will be no torque at the freewheel, so no chain tension, so no kickback. But what is fast enough?
Let's takes some well chosen numbers, so the maths are easy but that are in the ballpark of what would be expected.
A bike with 150mm of rear wheel travel, 1:1 ratio at the drivetrain (so 28t front, 28t rear for exemple), 30° of total kickback from 0 to full travel, (that's a high value but exists on many bikes on big cogs, measured with still wheel), and 750mm of wheel diameter (29er with serious tires).
This bike would use 5mm of travel for 1° of crank rotation from kickback, or 200°/m. Meaning a serious 1.8m/s suspension speed at wheel would give a 360°/s, so 1 rotation per second, and an even more serious 3.6m/s suspension speed would give us 2 rotations per second.
The wheel has a perimeter of 2.355 m so to go fast enough to disengage freewheel it would require a 2.355m/s (8km/h, a bit faster than fast walking speed) for 1.8m/s hits, and 4.710m/s (17km/h) for a 3.6m/s hits. Both of these scenarios are using wheel travel speeds that are unlikely to occur at those bike paces. That means kickback while coasting is a really unlikely thing. So there is no way to reduce a thing that doesn't happen. And that is a "disengaging freewheel" maths, not "engaging a freewheel with some ° of play".
Forces from clutches are in th sub 100N range. That means the chain inertia alone in enough to overcome it. Chain slaps happens so it proves that point. This is a negligible thing... And chain tension uses a ratio to action the suspension that is the same idea as you'd find in a single pivot bike between shock and suspension. But the chain is much closer to the IC than the shock on a single pivot. So any force in the chain that isn't close to a force existing in a shock would be negligible anyway, even at much higher numbers than 100N. So there is no way the clutch forces can matter outside placebo plane of existence.
But, I do think the Ochain is doing something. It removes rider input from small angles. If you look at the stairs videos, look closely to the crank movements: there is some up/down movements that are coming from rider input. This has several causes, like geometry and left/right leaning of the bike, rider correcting his fore/aft position, or reflexes, mistakes, or parasitic movements... These movements can put tension on the chain as they happen at speeds in the same range as pedaling speeds or higher. There, the few ° of lag from the Ochain can totally prevent these movement from creating any force in the drivetrain. Thus creating a real feeling of "lack of chain", that would be easy to confuse with kickback effects. Note that even if the speeds are in the ballparks, I lack more precise values or real datas to prove or disprove this point.
I didn't check the math, but your last point may be what brings a final and conclusive explanation to the "does pedal kickback actually happen in real life" debate.
It is baffling how unscientific are even some of PB's article's (for example the variables taken into account when doing "efficiency tests" on "multiple laps"). Our cognitive biases can be so strong, that taking a step back to see the situation as a whole is necessary, and that's what you're doing.
How about that:
www.pinkbike.com/news/review-hxr-easy-shift-crankset.html
regarding kickback it don't help at all, that's the same thing as a freewheel in the hub, but without the drivetrain ratio. You can remove the freewheel in the hub with the HXR.
The Ochain have some degrees of play, backed by some "spring", it adds to an existing freewheel in the hub that have to stay there.
Those two systems aren't doing the same thing so I don't really know what I can say?
How about with the wheel intermittently locking on hard braking?
It does exist
If your wheel is locked, The kickback isn't the same as what a software like linkage will show. It will be much lower, even in the negative values (wheel will turn around IC instead of being lifted vertically if that makes sense). That means the slack in the chain will be enough to hide kickback. And "intermittent" locking probably means too little movement to create much effect anyway.
If you brake enough to skid but the wheel isn't yet part of the swingarm, it will be a linear combination of these two effects, so still no kickback.
You could feel kickback on braking if you are pre-tensioning the chain, as a mistake, parasitic motion, or for whatever reasons. In this case, and this is the last point I made in my first comment, Ochain can delay the moment where kickback happen or erase it if the pre tension is minimal, but in this case the "real" kickback (from the bike) has minimal effect VS the rider's input. And that's precisely one of those cases where I do think the Ochain is creating a "chainless" feeling
The wheel intermittently locks when there is little or no pressure on the contact patch. The same forces (or lack thereof) that permit locking are likely to allow the suspension to extend, i.e. yes, the wheel may not be "spooling out" chain, but the suspension is not increasing chain tension at that time.
When the wheel connects with the ground, there will be a period when the total suspension system (including the tire) begins to compress and the wheel's rotation is not yet fully up to speed. The exact details of this transition are unknown to me, but it seems likely the wheel will be back up to speed before the chassis suspension has compressed enough to create significant kickback, even if the hub engages promptly.
Maybe the inertial forces of the chain could create a tug on the pedals during this event, but I suspect this force is small, relative to other forces on the pedals. Maybe the inertial forces of the chain are the main culprit behind the perception of kickback. Again, I doubt it, and we could test this by creating an extreme version of the STFU Bike device with tubes that tightly constrain the upper and lower runs of chain, or rigid bars of the same mass as the chain in place of an actual chain.
but I do have three questions:
-where is this 1.8 m/s suspension speed coming from? Has anybody with a telemetry setup found/published realistic values for vertical wheel speeds during bumps or is this a guess?
-the statement "unlikely to occur at those bike paces" seems misleading as you tend to coast in a gear that allows good pedaling cadence for when you need to sprint- albeit the kickback is theoretically lower in high gears, but also you would expect the speed the suspension moves is higher too, so analyzing a few design cases is maybe the best way to think of it.
-can we rule out a third, even simpler hypothesis that the chain slapping around that mad produces noticeable feedback? Of course it could also be any combination of these three distinct phenomena with varying importance.
I do agree that placing the blame on the clutches makes little sense, too.
1) 1.8 m/s is a speed I chose to round the maths. That's gives 1 rotation/s at the crank.
If you look at an histogram from a data acquisition of an average rider on a rough (and average or fast) track, You'd have a curve that starts high, with most of the time between 0 and 1m/s, then will start dropping between 1 - 1.5m/s to 2-2.5 m/s, and then you'll have the tail with rarer events at more than 3.5-4m/s. It can vary with suspension setting and rider's skills, but the 1.8 m/s is something already serious, that you'd expect from riding at more than 4 or 5 m/s (bike speed), and with a cogs that gives much less than 30° of kickback. I also did the maths with the 3.6 m/s, that is in, or at the start of the tail of an average histogram, and that also require a bike speed that's quite low.
2) I did the maths for a case that was the most likely to give kickback, but still plausible, and that gave a minimum bike speed that prevent kickback from happening. Yes, in a real bike, you'd coast probably faster with a gear that gives less kickback... meaning in real life kickback would be even more unlikely while coasting.
3) A 100g upper part of the chain with a 10gs acceleration would weight 10N, half of which would have to be loaded on the chain ring, and a third would be lost by trigonometry, meaning that you'd have about 3N hitting your cranks when putting 10Gs accelerations on your bike. That not considering real chain slap but a more homogeneous distribution of chain links position around a hyperbolic cosine, so it's a High value. 10Gs at the chain, long enough to be more than acoustic vibrations, is a big hit. A 36t chain ring (smaller will decrease the results), have a 73mm radius, so with 160mm cranks (bigger will decrease the results), it will put an extra force in the pedals of about 1.3N.
1.3N at the pedals, without calculating the vibration mode of the chain, elasticity or inertia of the cranks, and ignoring counter effects from lower link, that's pretty much no effects at all.
On most current bikes, the chain runs close chainstay, limiting downward movement of the chain's upper run. The lower run of chain is still free to bounce, of course, which can be minimized by a Bionicon C.Guide or similar, though the movements of lower run of chain tend to counteract typical kickback forces.
AI: “Lag in chain torque makes ratcheting through technical requires some acclimatization”
(its not just the autoplay keeping engagement low)
In another test, with 0 PSIg in the shock (equalized chambers, too) it took an average of 15 pounds to move the rear wheel through about half the travel (150mm total) with the clutch on, and an average of 14 pounds with the clutch off to move it the same distance. For reference, with 280ish PSI in the shock, it takes over 220 pounds to move through about 30% of the travel. So, again, the clutch any doing shit to the suspension. Got to be closer to 4-500 pounds to get half travel, so that's like a quarter of a percent at best that the clutch would add to the spring rate. And again, it's always part of the spring system, lower your spring rate and you can offset it if you feel you have to.
It is more comparable to sticky stanchions, which is something we all hate.
It's just that the leverage ratio of our rear suspension makes all this "sticky feel" of shock seals and derailleur clutch, quite small to be noticed.
All I can tell you is that the scale displayed different values when moving the cage or wheel with the clutch on versus clutch off, and this was quite repeatable.
*(yes there are position sensitive dampers, but they usually depend on bypasses or conditional circuits, and if the movement speed is beyond what the bypass can handle, or when the conditional circuits are engaged, then they again become speed sensitive. And obviously leaving out things like closed-loop electronically-controlled dampers such as MagneRide or such)
The point Uuno was trying to make (I assume) is that the friction clutch only exerts force against the direction of movement during this movement. Take a handlebar in one hand and grip it strongly. It now takes force to rotate the bar, but once you stop the rotation there is no force needed to prevent it rotating back. The bar is comparable to the derailleur pivot axle, the gripping hand is the clutch.
RE: breakaway force, I don't have a trace, this was in my garage with a bike/luggage scale, repeated a few times and averaged. But if you think the breakaway force of the clutch is a big deal, just watch some slo-mo of a mech cage in actual riding conditions. Even with a clutch, the cage is constantly moving as the chain gets bounced around, thus the breakaway force is constantly being overcome by just the mass of the chain. It's really not going to have much effect on the suspension, since that has multiples of the rider's mass working to overcome the breakaway force of the entire system.
And I am not sure what is a big deal and what is not. Coil riders say breakaway force of air spring seals is a big deal. So I am trying to find out how that compares to clutch forces before I form an opinion. I thought you might have some data on that.
• Far greater surface area of seals.
• Far greater surface area of bushings.
• 1:1 ratio, not 2.6:1 (average, obviously varies by bike).
• Can be subjected to bending moments in the ballpark of 1000 ft⋅lbf.
• Transmits force primarily to delicate hands, vs. robust feet.
If we can accept the friction of a telescoping fork, the difference in friction between modern air and coil shocks shouldn't even be a consideration.
That said, maybe we shouldn't be so willing to accept it. I'll spare you my soapbox ranting about the potential superiority of linkage forks ... for now.
But once it is steady in one position there is no force needed to keep it there.
In your experiment with the scale, that last part is important. Unless you record a time trace, it is very hard to tell what the clutch force is, because any value of the clutch force between 0 and the static friction will give the same sag.
I will just go ride my bike and let the pros with full telemetry setups figure out whether this system has any merits.
In that case, pedal bob should never be an issue, on any bike, either. At least on mellow climbs. Except that's where most people notice and hate it...
I think what they are saying is if you stay on the pedals this thing stays engaged just like a hub would.
Pedal bob is generally caused by the legs/body going up and down acting on the suspension. It's not necessarily an efficient motion but it is typically continuous.
That's one component of it, and one of the reasons why 100% anti-squat doesn't eliminate bobbing, but the main causes is moments about the instant centre due to chain tension and linear acceleration.
I've done extensive calculations on this (it's part of my job) and the ratio of impact to forward movement required to create kickback (with the wheel free to rotate) is greater than anything actually observed, other than maybe a trials-style wheelie drop.
If the wheel is locked, kickback is possible. Whether it's problematic is a separate question - and if it is problematic, it's another question whether the solutions are worth their drawbacks.
If the drivetrain is engaged via pedaling, kickback is inevitable. This presents a complex question of the ideal balance between kickback and anti-squat. Indirect drivetrains (ex. idler sprocket) can offer high anti-squat with low kickback (and different - possibly better - compliance), but they introduce other issues, such as weight, drag, and inconsistent geometry.
But everyone who has an OChain loves it, so something is going on.
"Calms down chain oscillations which leads to a quieter ride" is the truth and a very valid one, but I just find it weird that something is marketed when the science is so clearly wrong.
Discuss....
It could be that the ochain is more just acting as a type of shock absorber for your feet so you don't feel some of these forces more so that its actually eliminating them.
But here is the catch if the freehub is not engaged ( rear wheel spinning) then o- chain cant work because the hub picks all the rotation from kickback.
The reason why it works is because:
A) it dampens chainslap which is what most people interpret as kinematics caused pedal jick back
B) it allows suspension to move when freehub is locked (wheel not spinning)
The verdict on if this is worth 300euro is up to you
The rear center length grows as the suspension compresses, called "chain growth." The rear axle is moving away from crank as you bottom out. The derailleur has to extend to accommodate the chain growth, and the cassette and chainring need to rotate to allow the chain to "grow." Unfortunately, because your feet are holding a traditional crank and chainring in place, the chain can't grow evenly on the top and bottom. The cassette rotates and allows the bottom to "grow" faster than the top, and the derailleur spring and clutch are acting as a spring and damper resisting the movement.
Here's how and why I think Ochain works- Ochain allows the chain to grow in all places simultaneously. The cassette can spin, the chainring can spin, and here's the fun part: because the top of the chain can slip and move, the bottom of the chain doesn't have to "grow" as much. If there's less loose chain in slack at the top of the drivetrain, that means the bottom of the chain doesn't have to grow as much, meaning there's less movement in the derailleur, and less spring force and damping from the derailleur resisting your suspension movement. Thus- smoother.
And none of that has anything to do with hub engagement, because hub engagement doesn't occur above rolling speed.
I haven’t tried this device mostly because of the price, but if it can replicate the no chain feeling it’d be worth it to me
At first our team was sceptical, and maybe its not doing anything, but after a while they need to service them (One downside) and they take it off.... Only then to realise it was doing its thing all the while and the bike feels totally different without it and not in a good way.
It's not the be all and end all - I don't run one as I have different priorities for my bike than our Enduro riders and it has its downsides, but yes it works and yes I would recommend one to anyone thinking about it if speed is what you're after, it makes a difference.
They go on sale on our bikes in Jan ( in theory when we get stock in ).
Objective experience would be based on some kind of data or facts. Like in this case if you want to say this makes a bike faster, you’d have to present some data like time trials of runs with and without the ochain showing the ochain consistently outperforming the times without it.
I fully believe the Active Spider helps fight pedal kickback, since I've ridden with a loose direct-mount chainring and could both hear and feel it moving with the suspension movement.
But I also believe it could be equaled by minimizing chain growth in the suspension design at the cost of anti-squat. You claim that smooth pedalling will just squish the elastomers and keep them squished, with no "ring bob", per se. So the same should be true for the suspension: it will squat a bit and stay squatted, no bob.
I'd rather the more consistent traction under power of a lower anti-squat* than lower effective chain growth from what is effectively a stretchy chain.
*(Rear wheel downward force (normal force) less dependent on anti-squat trying to extend the suspension, meaning any pedal force changes have big impacts on rear wheel traction (static friction)
Yes, they do. A 20 degree, 18 POE, hub is, on average going to allow the cassette to go 10 degrees backwards before pulling on the chain. A 3.6 degree, 100 POE, hub, is going to allow an average of 1.8 degrees of movement before grabbing. That _will_ allow more suspension movement before pulling on the chain, over 5x more on average. Yes, above some wheel speed to suspension speed ratio, it won't matter. But considering how many people talk about how chainless is amazing for suspension feel, the system is under that ratio enough that it matters.
It's all speeds beyond a trials-style wheelie drop. For noteworthy kickback to occur, we're looking at a compression event near the maximum for which shocks are designed, at a brisk uphill pace - and that assumes the hub engages promptly.
Different story if the rear wheel is locked, though. In that case, the cassette is not "spooling out" chain, so kickback is more likely.
Also, short-travel bikes are usually for applications where weight and pedaling performance are more important, so the drawbacks are more significant.
www.pinkbike.com/news/williams-racing-products-release-new-centrehub-decoupling-spider.html
www.williamsracingproducts.com/shop/p/centrehub-pre-order
www.instagram.com/p/ChRRY7Qham6/?hl=en
www.pinkbike.com/news/review-hxr-easy-shift-crankset.html
The ideal drivetrain would be a gearbox with an ultralight rear hub, and something like the WRP Centrehub on the chainring.
"Chain vs. O-Chain vs. No chain"
Preferably with a few riders to add more data points.
Cheers.
One neg point : since i installed it, it tends to unscrew the crankarm. Now i check it before every ride.
Onyx hubs are the best hubs on the market for any bike without rear suspension.
On that low engagement hub vs O-Chain benefit, my hypothesis is that the low engagement hub, if it offered similar benefits, would be less consistent by comparison given the same degrees of rotation (when accounting for gearing ie: having a 32t chainring and a 32t cog selected) since we don't know where in the hub pawl 'pickup window' (eg: half way into a 6 degree pickup point window means that you are really at 3 degrees effectively when the rear wheel takes the hit and then tugs on the upper section of chain thereby generating pedal KB). So, you may need a VERY low engagement point hub to get similar benefits to the O-Chain. Something like a 28 or 32 POE hub would yield an average (median) engagement angle of between 6.5 to 5.5 degrees if we assume an equal distribution of pickup engagement within the full window of 12.85 to 11.25 for the 28 and 32 POE hubs respectively.
Hope that makes sense to someone other than me!
Also "the jury" is not really "still out there on the physics of pedal kickback". The how, when and why is decently well understood.
The question really is, wheter or not pedal kickback actually matters during riding. And there's some pretty solid research suggesting that in most scenarios it doesn't. (See: Gerth, M., Haecker, M. & Kohmann, P. Influence of mountain bike riding velocity, braking and rider action on pedal kickback. Sports Eng 23, 1 (2020))
I’m truly a fan and looking forward to one on my DH bike now. Both bikes have Onyx hubs and it’s a great pairing. I basically feel all the advantages of the ochain but practically zero of the cons regarding increased slack in engagement.
Highly recommend to anyone to give them a try
Also I remember OChain videos with ochain working when the wheel was not locked.
Anyway, I don't want to say that Ochain does not work, tried riding with no chain and it was marginally but noticeably smoother. What is interesting is a general mismatch between science based predictions and reviews.
Also I think that front freewheels does not do the same things as ochain (as suggested in some posts above).
Anyway, would buy it but I like using my 30T oval and would have to switch to a round 30T or 32T oval or buy a bigger cassette, so just need to wait when my drivetrain dies.
Here's another thought experiment: which "grows" more as the suspension compresses- the top of the chain, or the bottom? You can see pretty clearly in the "riding down stairs" videos from Matt in the article that the bottom of the chain is growing significantly more on the bottom than the top, which means the cassette and the crank both need to rotate to move chain slack from the top to the bottom. If the chainring can't move, the cassette will have to rotate twice as far to accommodate. Even when it's freewheeling, the cassette can't rotate instantaneously, resulting in more chain slack trapped at the top of the chain even while the bottom of the chain is growing as fast as it can.
With Ochain, the speed and volume at which chains can "flow" under turbulence doubles because the cassette and the chainring are now flowing freely. It's like doubling the size of a damper orifice- more oil can flow more freely.
I must say you had me convinced (eventually) last time that regardless of whether or not I can feel the difference on a bike with no chain, I suspect these o-chains don't achieve much unless your rear wheel is locked (which is admittedly more common than many would like to admit). But that is certainly a glowing review. There is something going on here. I dunno what it is yet, but there is something...
The physics on suspension-related kickback is indisputable: while coasting, kickback due to chainstay elongation is effectively impossible.
That's not to say there's no tug on the pedals. Some possibilities off the top of my head:
• Momentary slowing or stopping of the rear wheel due to braking forces as it skips along the ground. Perhaps a small amount of kickback can occur when the wheel contacts the ground. This feels unlikely, but I haven't looked into it.
• Chain movement due to inertia. If so, I doubt it has a significant effect, as the inertia of the chain is small compared to that of the rider and the forces on the rear wheel.
• Maybe we lock our rear wheels more frequently that we realize. Kickback certainly can happen under such conditions.
• Placebo. Never rule out the psychological effects of adding an expensive gadget, but always look for real effects first.
Still not buying an o-chain...I imagine that if they do anything they change ride feel, rather than race times.
But I also still maintain that my old super8 felt better with no chain. Perhaps thats a bit of an outlier as by modern standards it was borderline high pivot.
Anyway, I'll now let you return to ignoring the forums. It's probably sensible to be honest.
... or maybe the damper just choked when pushed and the resulting harshness was felt through the pedals. It's difficult to distinguish chassis and damper properties by feel.
I'm oot.
It's a system that works when loaded (ie when rider weight is applied to the pedals). Of course you will not see any difference if you just let the cranks free