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Stronglight 93 using only small chainring - which VO bottom bracket to buy?

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Stronglight 93 using only small chainring - which VO bottom bracket to buy?

Old 11-13-19, 07:31 PM
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polymorphself
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Stronglight 93 using only small chainring - which VO bottom bracket to buy?

Like title says, what mm would be safest bet here? Velobase is showing 118mm but I'm guessing I should shave a few off since it will only be one chainring.
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Old 11-13-19, 09:39 PM
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You don't have a pile of UN26s (or cheaper) for test-fitting?

Period catalogs suggest a 113mm for "pista" use. If you're going to use a single chainring on the outer position, I'd start there and see if everything clears.

Otherwise, if you're going to just use the inner position, I wouldn't change from the original 118mm at all.
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Old 11-14-19, 06:39 AM
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If you’re positioning the ring on the inside mount, you’ll still need a 118mm BB. If on the outside, you could probably get away with 115mm, but those shoulders for the inner ring on a mod 93 crank extend toward the frame quite a bit.
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Old 11-14-19, 07:42 AM
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I have run Stronglight 113 mm asymmetric spindles in both French and British-threaded Stronglight cups with a 93 fitted with a 45T ring in the outside position on several bikes. I wound up shaving the shoulders for the inner ring down to about half or less of their original thickness AND counter-sinking the backside of the chainring bolt holes on the spider to reduce clearance issues on bikes with round or round-oval-round chainstays. Not an issue so much when there are crimps for clearances.
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Old 11-14-19, 10:13 AM
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Originally Posted by ThermionicScott View Post
You don't have a pile of UN26s (or cheaper) for test-fitting?

Period catalogs suggest a 113mm for "pista" use. If you're going to use a single chainring on the outer position, I'd start there and see if everything clears.
Originally Posted by nlerner View Post
If on the outside, you could probably get away with 115mm, but those shoulders for the inner ring on a mod 93 crank extend toward the frame quite a bit.
Hmm, it will be mounted on the outside. Making this mixte a single speed. I trust you both...so 113 or 115?
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Old 11-14-19, 11:08 AM
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Originally Posted by polymorphself View Post
Hmm, it will be mounted on the outside. Making this mixte a single speed. I trust you both...so 113 or 115?
I would definitely trust the folks who've run this crank over me.


Having a chainline that's 1mm further out than spec is no problem, but scraping the paint on your chainstay sure is...
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Old 11-14-19, 11:42 AM
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Originally Posted by ThermionicScott View Post
I would definitely trust the folks who've run this crank over me.


Having a chainline that's 1mm further out than spec is no problem, but scraping the paint on your chainstay sure is...
If your best guess turns out to be a little bit short, you can always put a 1-1.5mm spacer under the drive-side cup. If your best guess turns out to be a little bit too long, you just have to live with it--although as ThermioicScott points out, a little bit long really isn't a problem.

In other words, don't sweat this too much. Whatever you choose will probably work out fine.
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Old 11-14-19, 12:41 PM
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Looks like the options jump from 113 to 116. Thinking I’ll go 113...

Last edited by polymorphself; 11-14-19 at 01:29 PM.
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