Bicycle Mechanics - Crank cap removal (pictures included)

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goombaboy
09-29-11, 01:54 PM
Im swapping components from my look carbon frame onto a colnago frame and i've gotten everything onto the new (old) bike apart from the crankset. What ive gotten stuck on is removing the crank arm locking cap. I guess its obvious but ive searched the web and found nothing. maybe im looking for the wrong thing. Anyway here is the picture, the crankset is dura ace fc-7701 and the cap i cant remove is the oone outside of the hex bolt.
http://imageshack.us/photo/my-images/690/cimg0056t.jpg/
cheers.
catchabadone
09-29-11, 02:12 PM
See those two little "dots" on the cap. Use a spanner or alternatively a small screwdriver and tap it with a mallet. You just have to unscrew the cap.
ultraman6970
09-29-11, 02:14 PM
U dont remove the cap.. those are self extracting bolts. Just crank the bolt from right to left (if im not mistaken because i have not used one of tthose in 30 years) and the crank will start coming out. U dont need a crank extractor for that.
CACycling
09-29-11, 02:16 PM
Those are self-extracting. Back out the allen and it will pull the crank arm off with it. Or, as noted above, you can use a spanner or just a puch and hammer to remove the ring.
ultraman6970
09-29-11, 02:17 PM
Some kids havent seen those things ever... big idea from shimano that wish campagnolo could have adopted back in the day.
goombaboy
09-29-11, 02:43 PM
Thanks for the help and yes i havent seen a self extacting crank like this before, in the end i just committed to undoing the bolts and the arms came straight off.
http://www.parktool.com/blog/repair-help/crank-installation-and-removal-square-spindle-type
HillRider
09-29-11, 07:24 PM
Some kids havent seen those things ever... big idea from shimano that wish campagnolo could have adopted back in the day.
Actually they way predate Shimano's use on their Octalink Ultegra and Dura Ace cranks. Suguino had "Autex" (Auto Extractor) self-extracting crank bolts on some models years ago and sold the bolt/outer collar sets separately as retrofit kits for their own and other brand cranks.
I installed one of the Suguino Autex kits on an 8-speed Shimano 105 square taper crank in the late 1990's for my S&S coupled travel bike to allow easy crank removal for packing.
Jeff Wills
09-29-11, 07:40 PM
Thanks for the help and yes i havent seen a self extacting crank like this before, in the end i just committed to undoing the bolts and the arms came straight off.
If you undid the bolts and the arms came off without using an crank extractor, they weren't on tight enough to begin with. The problem with the Sugino Autex and other older self-extracting crank bolts is that they make it very hard to tighten the bolts adequately. The crank bolt should be torqued to 25 to 25 foot-pounds... darn near impossible with a 6mm hex (Allen) wrench.
CACycling
09-30-11, 09:23 AM
If you undid the bolts and the arms came off without using an crank extractor, they weren't on tight enough to begin with. The problem with the Sugino Autex and other older self-extracting crank bolts is that they make it very hard to tighten the bolts adequately. The crank bolt should be torqued to 25 to 25 foot-pounds... darn near impossible with a 6mm hex (Allen) wrench.
They should come off by loosening the bolts, that is the idea behind self-extracting crank set ups. Never had a problem torquing down the bolts with a torque wrench and 6mm hex socket.
fietsbob
09-30-11, 09:58 AM
An alternative scenario, of the self extractor that is a cause of concern, is when the extractor ring
pushes the threads out of the crank arm , when the spindle wont budge.
and stripping the crank-arm is the weaker, path of least resistance, connection.
JohnDThompson
09-30-11, 07:35 PM
Some kids havent seen those things ever... big idea from shimano that wish campagnolo could have adopted back in the day.
Campagnolo *DID* adopt it for their Victory and C-Record cranks in the 80s, but unlike Shimano the outer ring was left hand thread to reduce the likelihood of the outer ring backing out of the arm and eventually stripping the threads in the arm.
Jeff Wills
09-30-11, 08:26 PM
They should come off by loosening the bolts, that is the idea behind self-extracting crank set ups. Never had a problem torquing down the bolts with a torque wrench and 6mm hex socket.
That's why I said "darn near impossible with a 6mm hex (Allen) wrench". The existence of those bolts made it seem like it was "correct" practice you use a short wrench to remove and install cranks. I saw more square-taper cranks ruined that way....
CACycling
09-30-11, 08:53 PM
That's why I said "darn near impossible with a 6mm hex (Allen) wrench". The existence of those bolts made it seem like it was "correct" practice you use a short wrench to remove and install cranks. I saw more square-taper cranks ruined that way....
I've seen plenty of stuff ruined by over tightening as well as under tightening. It isn't the tool required, it is the person using it that is the problem.
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