Road Compact Cranks on Flash Carbon
Anyone running road cranks on their Flash Carbon, or I suppose F29 if the frame is similar enough? Could this work or is the inside of crank to inside of crank too narrow? Would run only single 34t chainring on the outside.
The reason why I would like to do this is to get a power2max or Stages powermeter that I could use on MTB and cross bike and road compact with single 34t N-W would work gearing wise on MTB and for cross I could just run 42t N-W ring.
A dedicated road crankset wont fit, the ring may (or may not) but the actual crankarms are much closer to one another, they would hit the chainstays.
There is a way though and I am actually doing it... It requires a Cannondale Hollowgram crankset, the arms are the same for the road and mountain bike models but use different width bottom bracket to provide the needed clearance. So using the Stages powermeter, all you need is swap the non-driveside arm between bikes, it takes a minute (maybe two if you don't use the same pedals). I'm doing it across three bikes: one road, one cross and one mountain bike (although I probably wont use it often on the mountain bike).
Note that the newer Hollowgrams (SISL2 and 3D forged SI) have a different spacing than the previous Hollowgrams. Everything is compatible (arms, BBs, spiders, I actually use a road compact spider on my Scalpel with a single ring and an older narrower BB to get the best chainline and the smallest q-factor I could). The Stages Hollowgram is based on the new 3D forged SI, so installed on my older bonded Hollowgram SLs (Scalpel and CX bikes), the left pedal is closer to the frame so I have a pair of shoes with the left foot cleat offset to conpensate. Another way to center things would be to use a BB spindles without the non-driveside shoulder and play with spacers to be able to adjust the whole crank side to side...
You could also use a Hollowgram spider-based powermeter and swap it from one bike to another, again, using a mtb sized BB spindle on the Flash and a road sized BB spindle on the cx bike... Certainly doable, but swaping between bikes wont be as quick as with the Stages. All this assumes your cx bike has a BB30 or PF30 bottom bracket. A Hollowgram isn't cheap, but, it's probably the best crankset on the market (stiff, light and yeah, very adaptable).
You probably could use a mountain bike crankset on both bikes too... I hate having my feet spaced like a cowboy but, if you don't mind having a big mtb q-factor on your CX bike, that would be an option. You would have to thinker a bit with your ring position on the cx because the crank's spider will be a lot further outboard than a perfect chainline...
I'll add to Dan's typically superb reply....
All 3 bikes need to have the same spindle interface in order to accomplish this as Dan says, so it will solely depend on the types of bikes you have in the stable.
The best case scenario is all of your bikes having BB30/PF30 bottom bracket shells.
If you're lucky enough to have Hollowgrams across the board, this would be pretty simple to achieve with a crank based power meter such as Stages. Just swap the non drive side arm (pedal if needed) and roll...(again like Dan says). This obviously might be dependent on clearance issues as detailed above.
I use a compact 110bcd SRM for Hollowgrams and swap it between bikes (all have same crank arm lengths). It is a little more involved as you'll have to swap chainrings whenever you do it (and pedals, too, if needed). I also have SRM magnets installed on every bike.
There is speculation and probably data that indicate the need to recalibrate the SRM with any chainring alteration, but having done many calibrations/recalibrations, I can tell you that I haven't had a statistically different calibration curve with the same SRM and different rings. So I do not recalibrate with changes.
SuperX: single 40t Wolftooth
Flash: single 36t Wolftooth (you can also use any 34t road compact ring, but you'll need a chain guide)
EVO: 34/50t compact rings
I actually have a Hollowgram SRM compact for sale, but have been too lazy to list it, if you're interested, PM me. I always seem to have tons of Hollowgram odds and ends around too (spindles, crank arms, bolts, spacers, etc.)
Thanks guys for your informative posts. Hollowgram might be the way to go as my crossbike is a SuperX....Might be all C'dale fleet very soon as I might need to buy a complete bike with the Hollowgram. I have a road SRM, but maybe that will sell with my road bike.
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