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Item # SEM0021

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  • Black, 172.5mm-50/34 ($3,695.00)
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Item # SEM0021

The cream of the best crops.

Rotor cranks are among our favorites, both for their brutally industrial design, as well as their incredible stiffness and shifting performance. SRM is also among our favorites, as the accuracy of its power meters is tough to beat, and the integration of the power meter into various cranksets is top notch. No surprise, then, that we’re offering this combo. It’s simply the top dog in an increasingly-crowded field.

The SRM measures power output using strain gauges, and then transmits that data wirelessly to any ANT+-enabled head unit. It’s functional at essentially all cadences and power outputs, and delivers results with +/- 2% accuracy.

The Rotor crank arms pick up where drillium left off, but it’s executed in a refined, functional manner with none of the structural questions left by drillium. This is to say that every unnecessary gram has been precisely CNC-machined away, and what you’re left with is what you need, and not a bit more. The 839-gram combined weight for power meter, chainrings, and crankset is shockingly low, and gets us thinking what else we’ll need to add to get our bikes to UCI minimum, as the power meter was always kind of a handy boat anchor.

  • ANT+-compatible power meter that measures power output at +/-2% accuracy
  • Ultra-stiff crankset with 30mm spindle, compatible with BB30, BBright, PF30, and Rotor BSA30 bottom brackets

Tech Specs

Arm Material:
Arm Length:
170 mm, 172.5 mm, 175 mm
Chainring Sizes:
[standard] 53 x 39 t, [compact] 50 x 34 t
Bolt Circle Diameter:
130 mm
Bottom Bracket:
Rotor BB1 steel
BB Type:
BB30, BB Right, Rotor BSA30
BB Threading:
Compatible Components:
ANT+ compatible computers
Claimed Weight:
839 g
Recommended Use:
training or racing with power
Manufacturer Warranty:
3 years

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