This article originally appeared on BikeRadar
Danish bearing friction specialist CeramicSpeed is moving slightly outside of its comfort zone for its latest product: a complete rear derailleur pulley and cage assembly that the company says will save you up to 3W (based on a 250W output). The idea that bigger pulleys run faster is hardly revolutionary. The real question is how many folks will be willing to pay through the nose to get there.
CeramicSpeed outfits its new Oversized Pulley Wheel System with two enormous 17-tooth pulleys that will supposedly save nearly 2.5W over a stock Shimano Dura-Ace 11-tooth setup – and that advantage apparently grows another half-watt when using a less-than-perfect chain. According to CeramicSpeed, this is because the larger pulleys force the chain to bend less (and more slowly) per link for the same given rider speed, the pulleys themselves spin slower, and there's less tension in the lower span of the chain.
As compared to typical 11-tooth pulleys (at right), CeramicSpeed's new 17-tooth pulleys look comically large
Naturally, CeramicSpeed also equips the machined-and-anodized aluminum pulleys with its own hybrid ceramic bearing cartridges, which are built with tighter tolerances than the ones used in the company's standard-diameter pulleys to better handle the increased side loading.
Despite the huge increase in pulley size, CeramicSpeed says that swapping to its OPWS assembly will only add 8-10g to a standard Shimano Dura-Ace rear derailleur. The cage plates are molded from lightweight carbon-reinforced polyamide plastic, and the pulleys are very liberally machined. CeramicSpeed wouldn't divulge exact figures but the company also claims that there's essentially zero increase in aerodynamic drag with the bigger cage – at least when accounting for a realistically wide range of wind angles.
Liberal machining, lightweight carbon-reinforced polyamide side plates, and titanium hardware make for just an 8-10g weight penalty over stock
Thanks to the carefully designed cage geometry, an OPWS-equipped Shimano derailleur will accommodate cassette cogs up to 28-teeth in size – the same as stock – while supposedly making no sacrifices in shift performance, either.
CeramicSpeed says all of these friction claims have been independently measured by Friction Facts in Boulder, Colorado – the same lab that published the study on pulley size and drivetrain friction in 2013 that inspired the company to develop a complete pulley and cage assembly in the first place. Moreover, the latest round of testing has apparently confirmed that CeramicSpeed's new setup is now the fastest pulley system available, period, even beating out the widely heralded 13-15T Berner system often used by time trial and classics powerhouse Fabian Cancellara.
Not surprisingly, that sort of extra speed might be 'free' in the sense that you don't have to work any harder to get it but it's anything but free in terms of how much it'll drain your bank account. Retail cost for a complete cage and pulley assembly is a whopping $499 / €459 with CeramicSpeed's standard hybrid ceramic bearings, or an even more precious $600 / €539 with the company's even faster 'coated' bearings.
How much is extra speed worth to you?
CeramicSpeed is launching the system just for Shimano Ultegra and Dura-Ace 10-speed and 11-speed mechanical and electronic derailleurs for now, with production bits landing on store shelves some time around early October and SRAM-compatible versions to follow in later months.
The best way to go faster still is – and has always been – to train faster and better. But if you've reached your plateau (or just don't feel like working that hard), CeramicSpeed sure seems to have you covered.