Crank decision - 3D24 vs Force GXP

[mattjevans]

So having decided to get a P2M power meter, I'm now faced with the choice of which crank for a Trek Boone 9.

I have SRAM Red crank at the moment w CX1 ring, so it is tempting to get a Force CX1 crank and the P2M spider. This is the cheaper option as Force CX cranks are readily available at c£100

The other option is a Rotor 3D24 all from power2max. It's unclear which option is lighter/stiffer. Intuitively I think I should get the carbon Force, but I figure I'll throw it out there for comments.

Thoughts?

[Frankie - B]

I found myself thinking twice: 'get the force.' during reading your thoughts.

[racingcondor]

I have both the 3D24 and SRAM Force and when I weighed them with the chain rings off I seem to remember there was only 1g difference. Having said that the Rotor crank feels stiffer (I suspect if you look at the numbers it isn't so I don't know why).

For £100 I'd get Force though as it will save you £80+ unless you can get a very cheap set of Rotor.

[mattjevans]

So weight is basically even

The price difference between Rotor 3d24 full crank (incl tool) and SRAM spider only is £145. Force CX1 cranks are actually £120 unless I pick up one from eBay. So there's very little in it money wise, though with the Rotor I'd need to change my BB which would be a minor pain (it's BB90).

That said, the rotor crank interface looks slightly better than GXP? Pretty hard to find direct comparisons.

[stormur]

Rotor has 2 advantages : if you switch to Shimano / Campagnolo it still "fits" . Swapping chainrings is waay easier too ( not hidden bolt spider )- and you have "gazzilion" of options.

If you're absolutely 100% sure of using Sram "forever"- I would still choose Rotor ( frankly, I do have CX Sram Force22 equipped bike (exc brakes : TRP Revox here ) and Rotor crank.

[aram]

Rotor has 2 advantages : if you switch to Shimano / Campagnolo it still "fits" . Swapping chainrings is waay easier too ( not hidden bolt spider )- and you have "gazzilion" of options.

If you're absolutely 100% sure of using Sram "forever"- I would still choose Rotor ( frankly, I do have CX Sram Force22 equipped bike (exc brakes : TRP Revox here ) and Rotor crank.

Will the sram cranks not work with shimano? IS this new with 11 speed?

[mattjevans]

I think he means "fits" more as in aesthetic than whether it works. It's a good point

[stormur]

Exactly, that's why it was in "fits" not fits

[mattjevans]

I guess I should also consider Quarq riken. Same money. Heavier ?

[racingcondor]

Guess I should add that I'm on 10 speed.

I'd also say I've always found SRAM bottom brackets less weather resistant than (my only other experience) Shimano so that's a reason to go Rotor. Not a huge issue given the cheapness of BB's though.

I'm in the UK though and don't do as much maintenance as I should so if you're in a dryer country (or don't race through the winter like I have for the last few years), it may not bother you.

[jeffy]

Just because I happen to have just looked it up

Rotor 3D 24 110mm BCD 170mm arms = 530g (without BB & rings)

Praxis Clover 110mm 50/34 = 124g

Shimano 5800 Compact 50/34 170mm = 734g

[mattjevans]

Guess I should add that I'm on 10 speed.

I'm in the UK though and don't do as much maintenance as I should

Same and same