Bottom bracket type? Fit size, w: 70mm diam: 38mm
09-12-21, 04:32 AM
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Bottom bracket type? Fit size, w: 70mm diam: 38mm
Hello,
I have a fit size bottom bracket with a width of 70mm and an inner diameter (ID) of 38mm.
Will BB30 fit?
It's a road bike Gazelle Chamonix +-15 years old (and I can't find anything about it).
Thanks!
I have a fit size bottom bracket with a width of 70mm and an inner diameter (ID) of 38mm.
Will BB30 fit?
It's a road bike Gazelle Chamonix +-15 years old (and I can't find anything about it).
Thanks!
09-12-21, 05:10 AM
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Is it threaded? 15 year old bike most likely
https://www.parktool.com/blog/repair...0Thread%2DThru.
https://www.parktool.com/blog/repair...0Thread%2DThru.
09-12-21, 06:48 AM
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Not threaded. It has cups, fit size. I did a search for 'gazelle 38mm' and I found out that it's a Gazelle specific bottom bracket which are still for sale fortunately.. but I am doomed to have a square tapered bottom bracket again (I wasn't planning to drill out the frame until 42mm so I can fit BB30 brackets, but it's possible).
09-12-21, 09:13 AM
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Not threaded. It has cups, fit size. I did a search for 'gazelle 38mm' and I found out that it's a Gazelle specific bottom bracket which are still for sale fortunately.. but I am doomed to have a square tapered bottom bracket again (I wasn't planning to drill out the frame until 42mm so I can fit BB30 brackets, but it's possible).
But reaming a 38mm ID BB shell to 42 mm ID would increase at least part of the BB's inner diameter by 4mm - which is almost 1/6". Seems to me that would require be removing quite a lot of metal from the inside of the BB. Are you sure the BB shell is thick enough to allow that without compromising structural integrity?
09-12-21, 01:12 PM
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True, I am sure that it would become a pretty lame frame because outer diameter is 45mm (I am unsure of the usual thinkness of frame?). Lucky thing is that only the outer parts (~10mm) need to be drilled out more to fit a nice thread-thru BB30 bracket. Thanks for the reminder.
09-13-21, 12:01 AM
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... as no one ever said who had cotter pin cranks 
As a goose-neck frame road bike, the press fit bearings are fine. I am currently overhauling my 1983 Amsterdam, and other than the cotter pin removal the actual working on the BB is no more challenging than a front hub. Nothing lame at all, just an older technology. Enjoy it.
As a goose-neck frame road bike, the press fit bearings are fine. I am currently overhauling my 1983 Amsterdam, and other than the cotter pin removal the actual working on the BB is no more challenging than a front hub. Nothing lame at all, just an older technology. Enjoy it.
