Spanish company Rotor has a knack for producing innovative products in the search for extra performance, and its brand new Rvolver freehub is a good example of this approach, with a new freehub design that aims to reduce friction and provide super quick engagement
Due to be unveiled at Eurobike next week (the world’s biggest bike show and road.cc will be there) but early details released this week, the new freehub has got us really interested.
Rotor has developed a freehub comprising radial pawls that engage a floating ratchet ring. By having a floating ratchet ring, Rotor says friction when coasting is reduced, while a 15-degree engagement angle ensures instant pickup when you start pedalling. When you're pedalling the pawls and ratchet are engaged, but when you stop pedalling, the ratchet ring 'floats' away from the pawls, decreasing friction in the freehub. Perhaps the easiest way to get your head around it is to watch the video above.
The system also provides a lighter weight hub, Rotor claims, because the ratchet ring doesn’t use threaded parts and there are fewer internal components as well. Rotor also reckons it’s the easiest hub to install without the need for special tools.
The new freehub is housed inside a CNC-machined 7075 aluminium hub, made in Madrid, with “Intelligent Flange Design” notched flanges to reduce weight and provide easier wheel construction, with a choice of standard or 2:1 spoke lacing patterns. The hub is compatible with most current axle standards.
The new Rvolver hub will be available in October in road and mountain bike versions. The former will come in disc brake and rim brake flavours, with a disc hub weighing 230g and the non-disc hub 198g. Prices will be €328 for the rim brake hub and €344 for the disc hub.
A regular freehub (the part of the rear hub that allows you to freewheel) uses a ratchet and pawl system. It’s the most common design but there are many takes on its construction, with the typical aim of decreasing engagement time when you start pedalling and reducing friction in the system when you’re not pedalling the reasons for the wide variety of design, but they all share the same key principles. This video demonstrates how a conventional freehub/freewheel works.
“Existing 3-pawls and ratchet system hubs create rolling resistance due to friction buildup. By disengaging Rvolver’s ratchet ring from the hub’s radial and angular pawls when the rider stops pedalling, friction is greatly reduced, thereby decreasing rolling resistance and increasing coasting momentum,” claims Rotor.
Rotor isn’t the only company to look at the freehub as an area prime for improvement in the pursuit of more performance. Most recently Zipp has developed new Cognition hubs with an Axial Clutch that uses magnets rather than springs which it reckons reduces drag. And a few years ago Kappius Components came out with a very radical system with drive ring that engages 240 times in a revolution, four times more than a Chris King hub, with rare earth magnets instead of springs.
We'll have a closer look at the new Rotor Rvolver freehub at Eurobike next week.
More info at http://rotorbike.com/
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.