Elusive Bottom Bracket

For discussions about bikes and equipment.
COYB
Posts: 11
Joined: 22 Jun 2019, 11:41pm

Elusive Bottom Bracket

Postby COYB » 16 Mar 2020, 9:37pm

Searching for a Bottom Bracket 73 mm x 124.5 mm but they seem impossible to find. I've been told a 73 mm x 127 mm would work, as I could fettle the front derailleur but a 2.5 mm seems a lot to me. Any ideas please.

Brucey
Posts: 40498
Joined: 4 Jan 2012, 6:25pm

Re: Elusive Bottom Bracket

Postby Brucey » 16 Mar 2020, 10:24pm

In some cartridge BBs the spindle can be reversed in the cups and used the wrong way round; this can make a longer spindle at least give the correct chainline.

Alternatively if you can use a three-piece BB then you might be able to use thick-walled cups and a BB spindle meant for a 70mm shell to do what you want.

For example at SJS they have Neco cups (which I think are thick-walled although they don't say so) and you could use a 5S spindle with them. If it works as I hope it might fit nicely to a 73mm shell and give about the right chainline too.

cheers
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2_i
Posts: 28
Joined: 25 Feb 2020, 3:12am

Re: Elusive Bottom Bracket

Postby 2_i » 16 Mar 2020, 10:29pm

Could you work with spacers, positioning the BB asymmetrically?

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fausto99
Posts: 613
Joined: 19 Sep 2011, 10:06am

Re: Elusive Bottom Bracket

Postby fausto99 » 16 Mar 2020, 10:31pm

Those Shimano UNxx BBs can be used with a spacer can't they? Use the 73 x 122 + a spacer on the drive side. A Sturmey-Archer AW hub cog washer or two will do the job usually.

Valbrona
Posts: 2331
Joined: 7 Feb 2011, 4:49pm

Re: Elusive Bottom Bracket

Postby Valbrona » 17 Mar 2020, 6:27am

Could you not have the BB shell faced to 68mm if it helps the situation?
I should coco.

COYB
Posts: 11
Joined: 22 Jun 2019, 11:41pm

Re: Elusive Bottom Bracket

Postby COYB » 21 Mar 2020, 9:36pm

Many thanks for all the helpful suggestions regarding my " Elusive Bottom Bracket " which is now sorted. I have an embarrassing confession to make regarding the repair. I removed the BB to check ID, when I refitted it I used a torque wrench so the BB must have been loose all along. It must be an age thing, senior moment.

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fausto99
Posts: 613
Joined: 19 Sep 2011, 10:06am

Re: Elusive Bottom Bracket

Postby fausto99 » 22 Mar 2020, 8:03am

COYB wrote: It must be an age thing, senior moment.
I'm sure we've all been there :lol: