Using 70mm axle in 68mm bottom bracket
10-31-22, 10:41 AM
#1
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Using 70mm axle in 68mm bottom bracket
After taking apart the bottom bracket on a Gitane Tour De France I discovered a Shimano 600 axle, it is marked 70mm with a length of 121.4. Quite certain the cups are original Stronglight that the bike came with. It had a Sugino Mighty Competition crankset and currently using a Stronglight 49D. The question is can I use it as is? I imagine due to the French cups that the 70mm width is able to work, just an assumption. If anything I believe the adjustable cup is simply protruding more than it would though the threads go far enough into the bottom bracket.
All the parts appear to have zero wear so it looks to have been put together years ago and never used. I know there are pro and cons on loose versus caged bearings, there were 9 bearing caged which I will reuse, they are like new. If I change the axle I will go with 11 loose bearings.
All the parts appear to have zero wear so it looks to have been put together years ago and never used. I know there are pro and cons on loose versus caged bearings, there were 9 bearing caged which I will reuse, they are like new. If I change the axle I will go with 11 loose bearings.
Last edited by VintageRide; 10-31-22 at 10:45 AM.
10-31-22, 10:49 AM
#2
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I would ride it. No mechanical reason not to. As long as the chain line is within tolerance and your left foot doesn't feel like it is on an out rigger.....
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10-31-22, 10:54 AM
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It looks like it was a deliberate and successful attempt at matching a standard axle to thinner-than-normal Stronglight cups. I agree with the above -- if it fits well, there's no reason not to use it as is.
10-31-22, 11:14 AM
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Yep, that adjustable cup is out more than normal (about 2mm, I'd say). You could run it that way, but the more elegant way would be to put 2mm worth of spacers under the fixed cup.
An OCD comment about nomenclature: Axles are fixed rods around which something rotates. Rods that rotate within something (like bottom bracket shells) are called spindles.
An OCD comment about nomenclature: Axles are fixed rods around which something rotates. Rods that rotate within something (like bottom bracket shells) are called spindles.
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10-31-22, 11:37 AM
#5
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Good call on the use of proper descriptions regarding the various components - a bit sleepy headed but yes, spindle is the accurate one. Going to put it all together and see what happens. I should start liking for an appropriate Stronglight spindle though. At least Shimano 600 is good quality.
