Bearing and spindle issue

Tech Tech Help
1

Hello everyone

I am building a new bike. The frame has bb386 evo bb shell and I installed wheels mfg’s thread together bb. It was very hard to install my GRX crankset and it took more rubber mallet than I have ever used. I was eventually able to push the spindle through but was wondering what is the issue? Is it a question of two different definitions of 24mm or something else? Is it something to be concerned of? As I understand it an alignment issue between cups could cause something like this, but since it’s a thread together bb this shouldn’t be possible. TIA

2

Sounds suspect to me. If I were in your shoes I would probably remove the crankset and bb from the frame and check the frame to see if the bb holes are properly aligned and in spec in terms of dimensions.

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3

Those Wheels BBs don’t generally require much force to insert the cranks, even the ones with the step-down adaptors.

Did the BB install into the frame easily enough?

4

I can’t recall there was anything abnormal while installing the bottom bracket. On a side note Pedro’s pro bb socket with the holder is amazing tool!

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5

I would suggest sliding the chainset back out and measuring everything, in that case. If the aperture is too small or the axle is oversize (not a problem I have ever encountered with a Shimano chainset), that would be a logical explanation. If that’s not the case, then it must be an issue of alignment - either the bearings are not pressed into the BB cups properly, or the shell itself is deformed.

6

Was it relatively easy to slide the spindle through one bearing, and then difficult getting through the second? That would be alignment. You can confirm by installing the crankset in backwards, the first bearing should still be easy to pass through. If it’s not, then the second bearing is the culprit.

I have come across one instance (out of hundreds) where an Enduro bearing in a WheelsMfg bottom bracket had an out of spec, way too small inner diameter. It was for Dub, though, so the ID was not typical anyway.

I’ve also had issues with some angular contact bottom brackets.

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