's Forum Archives - Components

Archive Home >> Components(1 2 3 4 5 6 7 8 9 10 )

chainring bolts cracking(3 posts)

chainring bolts crackingmike r
Apr 30, 2002 3:01 PM
was swapping my 42 ring for a 39 today and found that 3 of the 5 bolts were cracked (the part that goes if from the frame side of chainring)
why did this happen?
wrong tension?
failure to clean the rings before tightening the bolts?
they are from a dura ace chainset.

i've replaced them but if they crack again could i reuse them if i don't have spares
re: chainring bolts crackingMike Prince
May 1, 2002 6:34 PM
The D/A bolts are alloy (vs. steel on the Ultegra and lower). I'm sure this saves a bit of weight but they are probably more fragile than the "heavy" steel bolts.

Not sure why they broke though. My crank is d/a as well and the chainring bolts are very tight. I would think that the hex heads would begin to deform before the rear bolt cracks, but go figure. I doubt that non-clean rings could cause this. Did you grease the bolts before screwing everything together? Alloy on alloy seems like a match made in hell without some grease to help things out.

Based on what you've said I would guess that the bolts were overtightened. If I had to replace them, I'd get the steel Ultegra bolts. Cheaper and IMO will be more durable. If memory is correct a set of d/a bolts is something like $25 while Ultegra is 1/2 that.
re: chainring bolts crackingDKF
May 5, 2002 6:57 AM
This is more common than you might expect. The key is to remove the chainring bolts annually, clean thoroughly, including the surfaces on the chainrings and the spider, regrease and reassemble.
PS - pay close attention to the placement of the chainrings when reassembling (write it down before you disassemble)