TXCiclista

I'm considering buying a new bike this month, and one of the things I'd like to do is find one that will take the "Stages Ultegra 6800 Power meter" (mostly because it's on sale and I'm too poor to spend more than $400 on a power meter (First World Problem if there ever was one!)). What I gather from discussions with the LBS is that the crank arm has to be compatible with the groupset, but I've either forgotten or never understood what specifically has to be compatible. Arm length seems obvious, but is the rest as simple as "the crankset itself that has to be the same group" (e.g. I need an Ultegra 6800 crankset for that power meter), or less obvious things like "as long as the bottom bracket will accept the arm, you're good?" I guess another way of putting this is whether I can actually try to fit a bike to the crankarm I have my eye on or visa versa. At this point, the bikes I'm considering will all be significant upgrades (moving from Tiagra to 105or Ultegra, alu frame to carbon frame, etc), so it seems to me that trying to fit the bike to a PM I can afford isn't necessarily crazy. But if it is, I'm open to hearing it.

WalksOn2Wheels

If your current crank is a Shimano crank using the Hollowtech II standard, you should be able to just slap that arm on the left side and go.

https://bike.shimano.com/en-EU/techn...lowtech-2.html

Check your chainstay for clearance:

https://support.stagescycling.com/en...s-power-meter-

WhyFi

Have you tried turning it off and on again?

WhyFi

Ooops - what WalksOn2Wheels said. If it's got a Shimano Hollowtech II crank on it, and you have the clearance, the 6800 Stages arm should work.

TrojanHorse

You can even mix and match if your OCD will let you have mismatched parts... 105 power meter on an ultegra crank or vice versa.