We review Rotor’s 3D Crank.
Rotor 3D Crank
£543 (inc 3D + CSET £339, 52/36 Q Rings £159, BSA BB Adaptor £45)
At the heart of the 3D system is a pair of aluminium crank arms that are both stiff and lightweight. The downside is that the profile is deeper than some cranks giving our size 10 feet just 2mm of heel clearance, which meant the occasional rub. The 3D+ version is designed to work with BB30 bottom brackets but Rotor offer bottom brackets compatible with all the major standards whilst still using the stiffer, lighter 30mm axle.
The chainrings and the ovalised Q-Ring design is claimed to offer a reduction in stresses to the knees, reduce fatigue and yet increase power. The theory being that by changing the effective diameter (chainring size) when your pedal stroke is at its least powerful – within 20° of the pedalling ‘dead-spot’ when you are neither pulling or pushing power. That allows you to move through this part of the rotation with less effort and get back up to full power sooner, maintaining speed with less overall effort. We selected a combination of 52/36, nominally called pro-compact. The ring shape reduces the size to around a 50 in the big-ring, and down to a 34 on the small. During testing we experienced a later onset of fatigue and less post ride muscle soreness.
With the system offering three settings depending on how you mount the rings, they do require plenty of experimentation before committing to one, and for this reason we wouldn’t recommend you fit them before a competition. Be prepared to adapt and experiment with them first. The downside of the oval design is that you need to heighten your front mech to accommodate the largest point meaning that at its thinnest there’s a significant gap on mechanical gears. That meant an occasional sluggish shift, though we didn’t experience the same problems with electronic groups, but we’d recommend using a chain catcher (Rotor offer one at £14.99) on both systems. As with anything that claims performance benefits, we got a few riders to test these. The best results came from riders with a more stomping pedal action – if you’re the sort of rider who pushes down through the cranks in an almost choppy running style we think the Q-Rings may well be a benefit. Those with a smoother style and higher cadence felt less difference. We couldn’t recommend the Q-Ring system across the board, but we’ve definitely seen improvements.
Excellent buid quality. We saw real benefits with Q-Rings, but they are not for everyone
This review was originally published in Triathlon Plus magazine. Save time and money by having every issue delivered to your door or digital device by subscribing to the print edition or buying digitally through Zinio or Apple Newsstand.
You’ll find loads more triathlon gear and kit reviews in triradar.com’s Gear section