Bicycle Mechanics - Shimano Hollowtech crank removal.

Last time I removed cranks were the ones with the tapered pins. My Gemini has Shimano Hollowtech cranks. I removed the plastic seal to expose the inner core of the crank. There is what looks like an 8mm hex socket. My guess is that I remove this first and that exposes the thread on the inside of the crank. The standard Park Tool crank puller I have will not fit, so I assume I need a special adapter to pull the crank arms off that screws into the crank arm and onto the shaft of the puller?

Has anyone removed these types of crank? I also presume the threads are conventional (anti-clockwise to unscrew) and don't use clockwise removal like pedal threads do?

I need to get these off as (a) I want to use a better bb, and (b) I damaged the front mech cage and it's one of those that fit onto the bb and not the downtube.

Help appreciated.

Last time I removed cranks were the ones with the tapered pins. My Gemini has Shimano Hollowtech cranks. I removed the plastic seal to expose the inner core of the crank. There is what looks like an 8mm hex socket. My guess is that I remove this first and that exposes the thread on the inside of the crank. The standard Park Tool crank puller I have will not fit, so I assume I need a special adapter to pull the crank arms off that screws into the crank arm and onto the shaft of the puller?

Has anyone removed these types of crank? I also presume the threads are conventional (anti-clockwise to unscrew) and don't use clockwise removal like pedal threads do?

I need to get these off as (a) I want to use a better bb, and (b) I damaged the front mech cage and it's one of those that fit onto the bb and not the downtube.

Help appreciated.The cranks are apparently not the self extracing type, where you just unscrews the fixing bolt and it bears against the protective cap to pull the crank?? Threads are standard right hand .You remove the bolt with an 8mm hex wrench. The threads for the crank puller are standard.You need the correct puller for the hollow BB spindle tho. www.parktool.com The old style puller will work if you drop a bolt into the spindle hole for the puller to work aganst.

You're pretty much right. There is a slightly different Park tool, that has a black handle, for removing hollowtech crank arms. That's obviously the "A" solution.

Some alternative answers:

1. Some cranks have self-removing rings that surround the crank arm fixing bolt. These can be identified by the two pin wrench holes in the dust cap. If you have those, just unscrewing the bolt with everything still in place should remove the crank arm.

2. Shimano made an adapter, that looks like a little metal hat, that you can use with your standard, blue handled park tool for removing hollowtech cranks.

3. In a pinch, I've used a nut that was the right size to fit in the crank arm as a substitute for the Shimano adapter. Unfortunately, a dime is just a smidge too big in diameter.

I seem to recall having something in the toolbox that I never thought I'd use. I put is somewhere safe, so safe I can't recall where, so if anyone knows where I put it, please let me know!

So, effectively, I remove the 8mm bolt and wind the crank off with the Park Tool I already have and with some sort of insert. I also guess that the cranks are stuck like sh1t on a baby's blanket. I suppose I should give them a good spray of WD-40 penetrating oil before pulling them off?

I also guess that the cranks are stuck like sh1t on a baby's blanket.

You might be pleasantly surprised about that. Normally they come off much more easily than the square tapered version.

Phew! I never did like baby's sh1t anyway! I recall the insert you are referring to. It was shaped like a hat and I got it to fit the blue-handled puller.

I take it the crank bolt needs a lot of muscle to shift that puppy? What kind of you-won't-read-this-in-any-book tip you can suggest to stop the crank arm rotating around the bb in the same direction you are trying to unscrew the bolt?

I take it the crank bolt needs a lot of muscle to shift that puppy? What kind of you-won't-read-this-in-any-book tip you can suggest to stop the crank arm rotating around the bb in the same direction you are trying to unscrew the bolt? Point the crank arm at the front wheel.Hold it with one hand. Point wrench handle at rear wheel. Use long enough wrench handle.Apply enough torque toward floor to loosen, while applying oppropriate force toward floor on crank arm.

Sounds good! Half the torque in each arm? I had visions of having to use a 6 ft lever to undo the bolt.

On the subject, how critical is the correct torque when re-fitting the bolt? I guess the old days of hand-tight and then 10 full turns are long over? :D

I have a decent torque wrench but I get the impression the torque values vary widely? I could not find anything at Shimano's website to explain the desired torque. The Barnett's manuals have a lot of information but I don't know if they take a middle-of-the-road approach as I can't find Hollowtech cranks mentioned specifically.

Sounds good! Half the torque in each arm? I had visions of having to use a 6 ft lever to undo the bolt.

On the subject, how critical is the correct torque when re-fitting the bolt? I guess the old days of hand-tight and then 10 full turns are long over? :D

I have a decent torque wrench but I get the impression the torque values vary widely? I could not find anything at Shimano's website to explain the desired torque. The Barnett's manuals have a lot of information but I don't know if they take a middle-of-the-road approach as I can't find Hollowtech cranks mentioned specifically.
Shimano says 305 to 435 inch pounds. But, I have never used a torque wrench on a bike.

Shimano says 305 to 435 inch pounds. But, I have never used a torque wrench on a bike.

So the days of hand-tight plus 10 full turns are still alive and kicking? I'd hate to think the old trusted techniques had passed into folk lore. :D

I used a torque wrench on my cranks. I haven't had any trouble yet.