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Old June 28th 20, 08:39 PM posted to rec.bicycles.tech
AMuzi
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Posts: 13,447
Default Crankshaft end tapers.

On 6/28/2020 2:08 PM, Dan S. MacAbre wrote:
Dan S. MacAbre wrote:
Is it possible that there are more than one kind of
taper? I recently had to replace the bottom bracket
bearings on the missus' Italian bike. I had to get one a
little wider (70mm, I think) and of smaller diameter than
most; but I got a Shimano one that fitted correctly. But
since then, the LH pedal bolt has tended to slacken
slowly, and the crank makes an embarrassing creaking noise
int time with the pedalling effort oscillating from left
to right. Is it possible that the Ofmega pedals fitted to
it are not fitting the taper correctly? No play can be
felt by hand, and they are still almost impossible to
remove without lots of unpleasant hammering with a tapered
car balljoint splitter.

Speaking of which, is there a tool that can get pedals off
easily? I had a tool that screwed into the side of the
pedal, but instead of pulling the pedal off, it just
pulled out all the alloy thread that it was supposed to
fit into. Again, is that because the Ofmega pedals have a
different thread there?


An Ofmega 68C crank has appeared on eBay here in the UK, but
it is sold with Shimano cups. Is it likely that the lock
ring will fit my Ofmega cups? Did Shimano make cups to fit
Italian bikes? The set is only £2 at the moment, but if
that ring fits, I wouldn't worry about having bought an
unsuitable crank. The item description doesn't include any
actual dimensions, so it could be a completely mismatched
set. I asked the seller what diameter the cups were, and he
seems to have used a ruler to come up with a width of 'just
under 35mm,' whereas mine are 35.7mm (probably should be 36).



Spindle matches crank.
Thread matches frame.

I and others set you on the path to the correct spindle.

Italian format is m36x24tpiW
British standard is 1.370"x24tpi (about 34.8mm)

Shimano, Ofmega and everyone else makes (or made) various
threads[1] for each of their products so you could, ideally,
buy their crank to fit into most bicycles[2]

Did your ebay vendor indicate what thread he's selling?
Shimano cup thread is well marked.

Also the lockring failure as described is most probably an
installation/maintenance error not an actual product defect.

[1] Some obsolete frame thread formats are abandoned now.
Crank makers more or less offer way too many push- or
press-in formats for modern cranks in modern frames. Choice
of six different frame thread formats was simpler IMHO.

[2] Generally but never universally. Not then not now.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


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