I have good success with the red crank and heel clearance, and I am sensitive to Q factor.
Also I am not sure if I want to be tied into the BB30 powermeter crank because I may replace the frame sooner or later, and a powertap wheel I can move between my bikes when needed.
BTW, if I put praxis rings do I need to recalibrate anything.
The arms use a similar construction method except for the obvious fact that Red cranks have an integrated spider and the S975 is removeable.
Recalibration on the SRM shouldn't be a problem as long as you torque chainring bolts to the specified amount (10nm I believe). For reference sake the S975 Quarq does require recalibration which you can do with an iPhone and ANT+ dongle. The new 2012 Red Quarq (which uses the same arms as S975) does not need recalibrating when chainrings are changed due to the updated Quarq.
As for BB30 or GXP S975. Either fit on BB30 or 68mm threaded frames with the appropriate adapter or conversion bottom bracket. The only compatibility problem is that BB30 can not fit in BB86 (or other 24mm spindle based press fit standards).
SRM don't list it for the sake of saying a number. If they did, and everyone destroyed their chainring bolts as you say they would, forums like this would be full of people complaining about excessive torque recommended by SRM.
If an aluminium chainring bolt does fail before reaching this torque it is either
-the chainring bolt has been removed and installed too times and reached its fatigue life
-has a manufacturing defect
Fwiw, Quarq for their SRAM 975 based powermeter 10Nm for steel chainring bolts and 8Nm for aluminum. Deviate from this and the calibration is way off. For some reason, Praxis chainrings have not been approved for use with the Quarq.
r_mutt wrote:Isn't the original poster talking bout Quarq and not SRM?
PoorCyclist aka Original Poster wrote:Looking into a power meter, if I replace my BB30 red crank with a SRM S975...
Definitely talking about SRM
itsacarr wrote:And if you really want you can just use one red crank arm for the other arm instead of the S975
This is not correct for the BB30 crankset. Red and S975 BB30 cranksets use different bearing preload systems.
It is correct for a GXP crankset though.
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