What size are my crank arm bolts?



p38lightning

New Member
Apr 19, 2004
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I recently purchased a 1983 Bianchi Alloro road bike(Italian manufacture), with very low mileage. It has Mavic wheels, but all the other hardware seems to be Italian. The crank only says Bianchi on the arms. Did Bianchi make cranks? I think that they are not Campy as there is no Campy logo as there usually is when they sub-contract. They might be Ofmega.

When I try to get a socket on the crank arm retaining bolts to remove them so that the arms can be extracted, I can find no socket which will fit. My LBS says that it should be a 14MM bolt but that doesn't fit. I tried grinding down the outside of the socket thinking that it was getting restricted by the hole in the crank arm from seating but that didn't work. Tried the nearest inch standard socket 9/16 no go. Tried 15MM, doesn't fit inside the crank arm hole, same with 5/8. Does anyone have any idea what my problem might be?

I'd like to add that there is no evidence that the crank was ever removed and I think that they are just as they were when Bianchi first installed them.
 

boudreaux

New Member
Oct 16, 2003
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p38lightning said:
I recently purchased a 1983 Bianchi Alloro road bike(Italian manufacture), with very low mileage. It has Mavic wheels, but all the other hardware seems to be Italian. The crank only says Bianchi on the arms. Did Bianchi make cranks? I think that they are not Campy as there is no Campy logo as there usually is when they sub-contract. They might be Ofmega.

When I try to get a socket on the crank arm retaining bolts to remove them so that the arms can be extracted, I can find no socket which will fit. My LBS says that it should be a 14MM bolt but that doesn't fit. I tried grinding down the outside of the socket thinking that it was getting restricted by the hole in the crank arm from seating but that didn't work. Tried the nearest inch standard socket 9/16 no go. Tried 15MM, doesn't fit inside the crank arm hole, same with 5/8. Does anyone have any idea what my problem might be?

I'd like to add that there is no evidence that the crank was ever removed and I think that they are just as they were when Bianchi first installed them.
The park crank extractor has a thin wall 14mm socket that has worked on everthing I have needed it to.
 

p38lightning

New Member
Apr 19, 2004
418
4
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boudreaux said:
The park crank extractor has a thin wall 14mm socket that has worked on everthing I have needed it to.
Thanks Boudreaux, if you didn't exactly have the answer to my problem you sent me in the right direction. When I went to Park Tools' website I saw references to 15MM 3 piece cranks on older bikes. While I didn't see the tool in their inventory, a visit to Ebay found 15MM tools. I ended up grinding down a $3.00 15MM socket (the outside diameter so that it would fit in the crank arm center hole) so I could use it with my torque wrench when I reinstalled the crank bolts. No Tucson bike shop had the tool, and most being largely staffed by younger folks had never heard of 15MM cranks....."you mean 14MM don't you?"

SO IF IT AINT 14 IT'S GONNA BE 15!