It’s been a while since we’ve had a “revolutionary” device that claims to
smooth the lumpy power delivery of the human “two stroke” engine, but this
is certainly the best engineered we’ve seen yet.
The RCK ROTOR crankset doesn’t use novelty shaped chain rings like Biopace, instead it relies on an eccentric bearing on the end of the bottom bracket axle. The movement of the drive side crank arm around this eccentric is then controlled by two small cams. These accelerate the crank arm through the “dead spot” at the bottom of the stroke of conventional cranks, but prolong its position in the power stroke phase (crank level with ground). The crank / eccentric reference points can also be slightly altered to tune the crank feel and amount of leverage in the power phase.
The Spanish designed units are really well put together and come with a long testimonial list of users, but the proof of the pudding is in the long term riding. Obviously a system like this feels “odd” to start with but we’ve got it on test now, and once we’ve got used to it we’ll let you know what we think. We’re particularly interested in how it will work on suspension bikes that normally suffer from pedal induced “bob” as we know oval Eggrings used to really calm them.
Engineers and anyone else who wants the full details and a more in depth technical explanation should head for the Rotor website.