Easton’s EC90 SL cranks share their exchangeable chainring system with sister company Race Face, which debuted the design.
Called Cinch it allows road, cyclocross or triathlon users to swap between single or double chainring setups, or alter single-ring sizes, in no more than five minutes.
It’s based on a light, aluminium 30mm axle, which is fixed into the non-driveside crank. The driveside crank has a ring with oversized splines behind it and the chainrings fit on to it.
Single rings are an all-in-one direct mount, narrow-wide tooth design, which does away with a separate spider and its bolts, whereas double chainrings bolt on to a forged aluminium four-arm spider with each bolt securing both rings in a 110mm BCD (bolt circle diameter).
After dropping the ring or rings into place, the Cinch lock ring is tightened by a Hollowtech splined bottom bracket tool securing them to the crank.
The BB30 axle slots in to the crank’s eight-lobed recess and, using an 8mm hex key, is torqued tight with a captive lock nut. This means that to swap chainrings, for example, at a cyclocross race after practicing on the course, you only need two tools and it’s easily achievable in no time.
The cranks are of hollow carbon construction and include a high-quality aluminium pedal insert. They’re straight and broad with a tapered rhomboid profile, and look utterly purposeful. Available in lengths from 170mm to 175mm, their Q-Factor (horizontal width between pedal attachments) is 149mm.
My 172.5mm cranks, including the 30mm axle, preload adjuster and cinch lockring weighed 340g. The four-arm spider with Easton 52/36, 11-speed rings weighed 238g making a total mass of just 578g.
Easton also offers 53/39 and 50/34 double-ring combinations and 40- or 42-tooth singlerings, plus a range of low-friction bottom brackets to fit almost every frameset. My PF30 68mm Cinch bottom bracket weighed 113g.
I tested the EC90 SL cranks with a Shimano Dura-Ace 9000 groupset (replacing a Quarq Elsa RS carbon crankset) with Dura-Ace 9000 chainrings. The overriding feeling throughout the test period was how rigid the cranks and chainrings felt, easily a match for those I had removed.
Whether putting maximum torsional stress through it when hammering uphill in the big ring, doing full gas standing starts or bothering the village speed limit with a signpost sprint, the EC90 SL ran true. I haven’t noticed any hint of deflection that could cause chain rub on the front mech, and shifting has been perfect.
It is possible to switch other cranks from single- to double-ring setups and back again, however, the simplicity and speed of the Cinch system is a real selling point.
The EC90 SL’s low weight and high performance are a very satisfying bonus but, as ever, it does cost.
The cranks have a hollow carbon construction and a high-quality aluminium pedal insert. Adam Gasson
One ring or two: The cranks take a direct mount, narrow-wide single chainring or two chainrings attached to a four-arm aluminium spider.
Stiffer than most: Only available with a 30mm axle the EC90 SL cranks have great lateral and torsional stiffness thanks to their oversized diameter.
All change: The driveside crank can be quickly removed with an 8mm hex key and the chainring(s) with a splined tool.