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Old 04-16-11, 05:56 AM   #1
Mccubbins
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malvern star (sportstar) bottom bracket solution

Hi folks, I've recently taken on a sportstar frame, late 70's early 80's at a guess, which seems to have an annoyingly unique BB. no thread with locking tabs. the bb itself has a lockring on the non-drive side only and it's a cotter pin design.

the bb I have is still useable so things aren't desperate as yet, but I'm spending alot of time on this bike and I'd like to fit a sealed square taper to give me a wider and lighter selection of cranks. anyone out there had the same problem? Is there a solution?
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Old 04-16-11, 06:44 AM   #2
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I just measured the shell, 38mm ID. if that helps any?
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Old 04-16-11, 11:35 AM   #3
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38mm ID? That's going to be tough. I suspect that it needs some sort of proprietary Malvern bottom bracket. Are you in Australia? Perhaps you can scare up an old one someplace.

I'm not sure if a modern threadless cartridge BB would work with a 38mm ID, but perhaps a shop would let you try it.

Otherwise, you may need to braze a threaded sleeve inside the current shell, or pull the entire shell and replace it with a more standard one. Neither of these options is likely to be cheap, so unless you can do the work yourself you may need to consider another frame.
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Old 04-16-11, 12:18 PM   #4
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You sure it's 38 mm nad not 40? 40mm is the size most Thompson style bottom brackets are. If you can find one, of course.
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Old 04-19-11, 05:25 AM   #5
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yeah definately 38. The frame just isn't worth that much trouble (hi-tensile, pressed head lug and dropouts) so I'll just put up wit the massively heavy BB and crankset I have. put some money into a future build.

thanks for your help guys!
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