JoeO

I just got a new bike with a Shimano FC-9100 P crank. It's the one with their power meter. I was about to remove the crank and put on a different chainring -- something I've done many times before with DA 9000 and 9100 cranks -- when I noticed that it's quite different from my another FC-9100 that I own (one without power). Apparently there is a new, special Shimano tool involved in installing the thing called the "TL-FC40 Crank Arm Tool" Universal Cycles -- Shimano TL-FC40 Dura Ace Power Meter Crank Tool [YEZY00017]

Even after reading the Shimano Dealer's manual it's still not clear to me: Do I need this tool to just take the crank arm off/put it back on? Or is that just something that's used for one-time power-meter installation? I don't want to try to force anything if I need the tool

(Normally I'm used to just undoing the bolts and sliding the crank arm off but I'm not sure if that will work here.)

rubiksoval

Is this to remove the tensioning bolt?

If so, the above makes it sound like you don't need the tool, but it may make it easier to avoid mangling the wire.

JoeO

Finally just said, the hell with it and monkeyed around with it Turns out my bike shop had given the me the tool (didn't realize that, almost bought one). Apparently the tool -- along with the spider-ring that it removes -- is basically the new version of the previous crank pre-tensioning cap on many, many previous DA/Ultegra/105 cranks.. It's just that in the 9100P, it is now more internal, hidden under a little aero--cap that you basically pry off.. So you 1. pry off the little aero cap, 2. unplug the power-meter wire, then 3. Hold the wire out of the way while you use the tool to unscrew the little plastic pre-tensioning spider. After that it's business as usual.