Designed to mitigate the surprisingly harsh effects of a chain slapping about, Rimpact’s Chain Damper is a sure-fire method of smoothing out your mountain bike’s ride. In fact, it’s incredibly effective, but for that rather serious benefit, it brings a range of compromises into the mix which makes the Chain Damper a product that’ll please a niche audience but one that’s looking to wring the absolute most out of their descending performance.
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Rimpact Chain Damper - Technical details
Ever since Aaron Gwin’s historic World Cup win at Leogang in 2015, after snapping his chain at the top of the track, pedal kickback and the chain’s influence on suspension performance have been hot talking points, even 10 years later. Since then, high-pivot mountain bikes (although nothing new) and a whole range of tech have been developed, all in a bid to smooth a bike’s ride in the pursuit of speed.
Pedal kickback has been a subject on everyone’s lips for years now, whether you believe it’s a thing or not. Rimpact, the brand best known for its tyre inserts and Tuned Mass Damper, falls into the latter category. Instead, it believes that the energy the chain creates as it ‘slaps’ results in greater feedback, although in certain situations, pedal kickback can occur, which the Chain Damper can also address.
The Chain Damper is a surprisingly simple bit of kit made up of two 7075 aluminium plates that sandwich a special chainring. The movement of that chainring is then damped via two springs with four elastomers at each end of the chainring’s stroke, for lack of a better term. Those elastomers also control a five-degree negative stroke.
It’s then available to fit Shimano, SRAM 3-Bolt, SRAM 8-Bolt Transmission, Hope Direct and Racefact direct crank fitments. It can also be picked up in 30, 32, 34 and 36t chainring sizes. Spare springs, chainrings, and a service kit, including fresh seals and elastomers, are available as aftermarket replacements.
At the moment, there isn’t an e-bike-specific model, but there is one in the works.
As for weight, the Chain Damper comes in at 282g, which makes it far weightier than a regular chain ring, but this is no regular chain ring.
Rimpact Chain Damper - Performance
The installation of the Chain Damper is exactly the same as installing a new chainring. I ran the damper on my ‘21 Canyon Spectral with a T-Type crank and 55mm chainline. It’s merely a case of bolting the thing on, but with everything torqued to spec, frame clearance is incredibly close. I ran the Chain Damper as is, but Rimpact recommends adding a spacer to boost clearance a little. Of course, this will offset the Q-factor a little, so it’s not a perfect fix, but it’s unlikely that a millimetre’s difference in pedal spacing would be noticed.
Once installed, the Chain Damper makes a huge difference to a bike’s ride for better and for worse. When pedalling, it provides a mighty peculiar character at the bottom and top of the pedal stroke, where power typically isn’t generated. It’s a tricky phenomenon to describe, but the damper disengages and reengages as power is dropped and picked back up throughout the pedal stroke.
So when a foot is at the very top of the pedal stroke, resistance, for lack of a better term, lightens momentarily and as soon as the chainring butts up against the internal elastomers, it returns. The result is a noticeably inconsistent power transfer during low-watt efforts/high cadence. That’s the Chain Damper’s main drawback, and it overrides the benefits of a high-engagement freehub as it takes a good few degrees of rotation before the Chain Damper engages.
This is something to get used to, and the negative feeling fades after a few rides. However, during lower cadence and high torque efforts, the Chain Damper is always engaged, so power transfer in such situations (like climbs) is much more consistent.
But where the Chain Damper makes up for its pitfalls is when descending technical and lumpy terrain, where it does exactly what it’s designed to do - isolate the chain’s influence on the crankset. In turn, it rewards with a beautifully smooth-feeling ride over terrain that’s anything but. At first, it’s an odd feeling, but once accustomed, it brings a whole new level of control and comfort.
Where the Chain Damper is designed to reduce the effects of chain slap, I’ve been very surprised by how much chain slap influences the way a bike feels to ride. The Chain Damper works hard to erase the harshness of the feedback felt through the feet. As that feedback isn’t really a thing with the Damper at work, it’s allowed me to push harder into high-speed technical terrain with full composure. It brings a real benefit to flat pedal users, too, since the crank isn’t being tugged by the chain, thus providing a more solid and stable platform for feet to adhere to.
It’s very well damped at that. A lot of work has gone into testing and refining the spring rates of the internal springs and the density of the elastomers. Apart from the low-wattage pedalling character, the Chain Damper brings no compromise to a bike’s ride on the descents, as there’s no harsh feeling when the damper knocks against the elastomers. Everything is smooth.
There’s a clear boost in rear-wheel traction, too. As the chain has less of an effect on suspension performance, it’s freer in its movement, and it’s simply more supple throughout the stroke.
When it comes to products like this, sealing and weatherproofing are two points that are high on the list, as others haven’t quite cut the mustard. But I’m pleased to say that the Chain Damper is very well sealed. I’ve spent most of my time with it riding through winter and everything that comes with it, as well as some seriously dusty days. With all of that considered, the Chain Damper’s internals have remained squeaky clean, only with some of the elastomer’s colour bleeding into the grease.
It’s super easy to service, too. Unwinding four 3mm allens opens up the unit that contains just two springs, four elastomers, two labyrinth seals, and a smaller o-ring-type seal. Cleaning or replacing each of the components is delightfully simple, only requiring a smidgeon of finesse when it comes time to bolt the damper back together. Though it must be noted that for the best performance, Rimpact recommends a lithium-free suspension grease. The brand also suggests servicing only when a squeak begins to occur, which, during my several months with the Chain Damper, has yet to happen.
Although there’s a bit of wear to the elastomers where impact has clearly occurred, the rest of the chain damper remains free of any serious wear, inside and out.
Rimpact Chain Damper - Verdict
There aren’t that many products on the market that do exactly what the Chain Damper does, but there are some that are built to reduce to effects of pedal kickback, which the Chain Damper does, but that’s not its main purpose. O-Chain is the key competitor. It’s more expensive at £339, it doesn’t come with a chainring, and we’re told that it’s not as effectively sealed. However, it is adjustable.
Then, e*thirteen has developed its Sidekick system - a pedal kickback reducing freehub. The price of entry here is at least £400, but that will get you a full wheelset.
As I’ve mentioned before, the Rimpact Chain Damper is for those who are seeking speed and control during the descents, so for those who want to smooth out their ride when tackling fast, repetitive hits, it’s a no-brainer. It’s well-damped, impressively sealed, and it does what it’s built to do - dampen chain slap. It’s not without its compromises, however, as it brings a weight penalty against a regular chainring, and it brings a weird pedalling characteristic with it.
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