BB and chain line
04-11-20, 04:28 PM
#1
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BB and chain line
My Dura-Ace 7600 crank is supposed to have the standard 42mm chain line with a 109mm ISO spindle, but I recently measured and discovered that the line is 45mm. The Dura-Ace hub puts the cog at the proper 42mm. The difference explains why my chain ring wears on the outside, and might explain why the drive train is not always as quiet as claimed for fixed. And maybe part of why I've gone through most chains in less than 1,000 miles (the other part being gravel roads.)
The bottom bracket is the NJS-approved, ISO Hatta. Shouldn't ISO spindles made to this high standard -- and presumed tight tolerance -- interchange among brands? I've never read anything suggesting otherwise -- that I should buy a Dura-Ace BB for my D-A cranks. And I cannot find a 7600 bottom bracket to see if it matters. I called Shimano, whose rep couldn't help resolve the problem.
Can anyone out there, before I call Phil Wood?
The bottom bracket is the NJS-approved, ISO Hatta. Shouldn't ISO spindles made to this high standard -- and presumed tight tolerance -- interchange among brands? I've never read anything suggesting otherwise -- that I should buy a Dura-Ace BB for my D-A cranks. And I cannot find a 7600 bottom bracket to see if it matters. I called Shimano, whose rep couldn't help resolve the problem.
Can anyone out there, before I call Phil Wood?
04-11-20, 06:09 PM
#2
It's the little things
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I guarantee your chain is also tensioned too tight. Chainline, in my experience, is sometimes trial and error.
04-12-20, 08:55 AM
#3
Your cog is slipping.
Over-thinkers are under-achievers.
