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With over a century of refinement behind them, the roller chains used on modern bicycles are incredibly efficient, remarkably strong and durable, and relatively inexpensive. There’s always room for improvement, though, and UK company New Motion Labs has introduced a completely different design that not only promises better efficiency, but also decreased wear throughout the entire drivetrain, and all without the need for laborious cleaning and lubrication procedures.
This isn’t just some lab experiment, either. They’re soon going to be used in top-tier UCI track races.
The problem with roller chains
The thing that makes a roller chain so good is also arguably its fundamental flaw. As the roller engages one side of the chainring or cassette sprocket tooth, the roller rotates slightly as slides into position. This minimizes sliding friction between the chain and chainring or rear sprocket, but also creates friction within the chain itself. In addition, even when a lot of chainring and sprocket teeth appear to be engaged, current chains still mostly transfer power through just a few teeth. This concentrates stresses to a small area, which accelerates wear (especially for riders putting out a lot of power) and creates another source of friction.
In recent times, we have seen a lot of time and money pumped into minimizing these losses. Most serious time trial and track racers have an array of gadgets to ensure their chains are optimized to the nth degree, and ultrasonic cleaners and slow cookers full of wax are now part and parcel of race prep. We’re also seeing increasingly larger chainrings and sprocket combinations, alongside similarly oversized jockey wheels, all in the name of saving even fractions of a watt.
All of that is working, too, with independent tests showing properly race-prepped drivetrains to be as much as 98% efficient.
That elusive 2%
As good as chain optimization has become, there comes a point where there’s no more optimizing left to do, and there are no other options but to rethink the system.
The future apparently isn’t far away, as New Motion Labs has developed a new Dual Engagement chain that is supposedly able to transfer high power on both sides of the tooth, over nearly all the teeth available to the chain. The claims are certainly attention-grabbing: “the most efficient chain ever”, “four times increase in system lifetime”, “ability to transfer 25% more Torque”, and “a decrease in peak stress of 30%”. Basically, the holy grail: more power, more durable, and reduced frictional losses.
The key difference with the Dual Engagement chain is how it interacts with the sprocket teeth. Instead of just one roller pushing on one side of the tooth, the Dual Engagement chain wedges each tooth in between two chain pins. According to New Motion Labs, because the chain engages on both sides of the tooth, it is effectively locked in position, theoretically spreading the power distribution over many teeth, increasing efficiency, and reducing wear.
New Motion Labs is working across an array of industry applications, but in terms of cycling, the current version of this new chain will only be compatible with track bikes and some E-bikes. It is in final testing phases and New Motion Labs aims to see their chains on the track at the Tokyo Olympic Games. There are a number of final design and manufacturing decisions that need to be finalized in the next round of testing in January, after which New Motion Labs will be in a position to start supplying chains to track teams and riders. New Motion Labs has already partnered with the HUUB-Wattbike and Spellman Dublin Port UCI track teams in the development process, and these are likely to be the first teams we see using the chains.
Initially, the new track chains will require a unique tooth profile, so New Motion Labs will offer a complete package that will include a chain, chainring, sprocket, and lube. Exact pricing is to be confirmed, and New Motion Labs is also finalizing the exact lube that will be supplied. This will be determined by a series of efficiency tests to be done at the University of Bath on a specifically designed testing rig that has a much greater resolution than even the most accurate power meters can provide. Given the purported fundamental design advantage, New Motion Labs is confident that waxing chains to achieve efficiency gains will be a thing of the past.
Could we see these chains on more bikes?
I asked New Motion Labs CEO Marcel Fowler if the Dual Engagement chain was something we could possibly see on other forms of bikes in the future, and specifically, if it was compatible with a derailleur system. To my surprise, Fowler explained that the company is currently in the testing phase of a road-going prototype of the Dual Engagement chain, and expect that it will be finalized in the near future. This version will be compatible with a derailleur system and could offer all the claimed benefits of a Dual Engagement chain to the bikes we ride every day.
We currently have three major drivetrain manufacturers and an ever-decreasing cross-compatibility amongst them. So how we get to the point where we see a Dual Engagement chain on new bikes we see in shops? Fowler explained New Motion Labs is primarily a design house, and rather than try to diverge into manufacturing and retailing, it instead intends to license the technology to manufacturers. If Campagnolo, Shimano, or SRAM can license the technology and incorporates it into their own drivetrains, it is much more likely to end up on our bikes than if it was to remain a niche marginal gains upgrade aftermarket option.
In terms of benefits for a road-going bike, Fowler was confident the opportunities are vast. The reduction in force localization and peak stress reduction means the Dual Engagement chain could open up options in terms of sprocket materials and design. For example, Fowler explained that some riders are currently experimenting with carbon fiber sprockets to reduce friction, but due to the huge forces applied when just a few teeth are engaged, there isn’t sufficient durability to make that material a viable option. With the Dual Engagement chain and its reduced stress and shared load, we could potentially see thinner and lighter sprockets made of very low-density materials that could offer a reduction in overall drivetrain weight (although the chain itself looks to be substantially heavier). There could even be options to design self-lubricating plastic polymer sprockets. And of course, thinner sprockets might also mean we can fit more onto a freehub – 2×20, anyone?
Lots of questions
As interesting as the Dual Engagement design sounds, there are certainly a number of unanswered questions. It’s unclear at this point, for example, if New Motion Labs’ numerical claims are based on theoretical calculations or objective data. And if the numbers are based on actual test data, what were the test conditions? How would a Dual Engagement drivetrain withstand water and grit? Would the claimed properties degrade with wear? What might a Dual Engagement drivetrain cost relative to a current conventional one?
This is a topic we plan on investigating further, so stay tuned for more in the weeks ahead.