Campag square taper bottom bracket

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bazzo
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Joined: 27 Jul 2012, 7:37am

Campag square taper bottom bracket

Post by bazzo »

I need a bit of advice, came across a frame with a Campagnolo Mirage square tapered bottom bracket. I presume it is an Italian threaded frame.

Can you fit a Shimano compatible chainset to it?
If I fit a Campag chainset can I use Shimano cassette.
My guess is it’s for 9 speed, would anyone agree or disagree.

Any opinions or observations welcome.
Valbrona
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Re: Campag square taper bottom bracket

Post by Valbrona »

Campag makes bottom brackets for both BSA and Italian threaded frames. The best thing to go on is the frame: Is it made in Italy? Or the cups may carry lettering.

Campag spindles are ISO taper; Shimano are JIS taper. The two types are non-compatible.

Sure you can use a Campag crankset in an otherwise Shimano group.

A BB spindle is a BB spindle. You don't get 9 speed, 10 speed, and so on. The only two real types of Campag BB spindle you get are long ones for triple chainsets, and shorter ones for double chainsets.
I should coco.
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Mick F
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Re: Campag square taper bottom bracket

Post by Mick F »

............. and for different widths of seat tube.
Chainline is everything.

My Campag Chorus (just the same as Record) BB is 111mm on Mercian. Triple, and on an old fashioned 531c frame.

Screen Shot 2021-05-14 at 16.06.45.png
Mick F. Cornwall
slowster
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Re: Campag square taper bottom bracket

Post by slowster »

Measure the BB shell width. BSA is 68mm, Italian thread is 70mm. Opinions vary somewhat on fitting JIS cranks to ISO square tapers. Sheldon Brown reckoned it was acceptable, subject to the proviso that the resulting chainline was compatible with the rest of the transmission. If it were me I would probably replace it with a JIS square taper given the easier availability of good value JIS cranks, especially if I had a suitably sized Shimano UN55.

https://www.sheldonbrown.com/bbtaper.html
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SimonCelsa
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Re: Campag square taper bottom bracket

Post by SimonCelsa »

Dug this old reply up from another forum which sums it up quite well:
Campag (ISO) and Shimano (JIS) tapers are different. They are both 2 degree tapers that start abut 12mm wide. But ISO ones are .2mm narrower at the start (IIRC) so a JIS crank on an ISO taper will go further in than it should and and an ISO crank on a JIS taper will not go as far as it should. Whether this will make a difference will depend on the crank shoulder and whether there's not enough or too much taper in the hole. The chainline will be different too if this matters.

Best to use the right taper if you can, if not it may work fine - or not.
Seems about right from my limited experience!
bazzo
Posts: 221
Joined: 27 Jul 2012, 7:37am

Re: Campag square taper bottom bracket

Post by bazzo »

Valbrona wrote: 14 May 2021, 3:55pm Campag makes bottom brackets for both BSA and Italian threaded frames. The best thing to go on is the frame: Is it made in Italy? Or the cups may carry lettering.

Campag spindles are ISO taper; Shimano are JIS taper. The two types are non-compatible.

Sure you can use a Campag crankset in an otherwise Shimano group.

A BB spindle is a BB spindle. You don't get 9 speed, 10 speed, and so on. The only two real types of Campag BB spindle you get are long ones for triple chainsets, and shorter ones for double chainsets.
[/quote

It is an Olmo frame, so most likely Italian threads.]
boris
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Re: Campag square taper bottom bracket

Post by boris »

For a while I used a Campag Chorus 8speed double chainset mounted on a Shimano UN52 bottom bracket. I got problems with the positioning of the front and back changers, so I got a campag bb instead and , as the above comments would predict, all worked better. I think the campag chainset could not get close enough to the frame The UN52 was 111mm if I remember correctly. Maybe a 107 would have worked, but I was using what I had.
soapbox
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Joined: 27 Jun 2009, 12:20am

Re: Campag square taper bottom bracket

Post by soapbox »

With a bit of faffing about, it's possible to shim a spindle if the crank goes too far on. Drill a hole in some aluminium or tin sheet, big enough for the bolt to go through, then cut out a cross surrounding the hole that can be bent to fit over the spindle taper. Messy, but it works fine.
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531colin
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Re: Campag square taper bottom bracket

Post by 531colin »

bazzo wrote: 14 May 2021, 3:42pm I need a bit of advice, came across a frame with a Campagnolo Mirage square tapered bottom bracket. I presume it is an Italian threaded frame.

Can you fit a Shimano compatible chainset to it?
If I fit a Campag chainset can I use Shimano cassette.
My guess is it’s for 9 speed, would anyone agree or disagree.

Any opinions or observations welcome.
Bottom bracket bearing units are a cheap consumable; don't let the availability of a cheap consumable decide what drivetrain to use.
The most important thing is to establish that this BB unit isn't corroded in, because if it comes out, then you can use any drivetrain components you like. Shimano tapered axles are available in Italian threaded cups, so even if its an Italian threaded frame, you can still use Shimano (etc.).
If it won't come out, the frame is of limited use anyway, and you will need to find a chainset which fits that particular axle length. BB axle length is governed by the chainset, not by how many sprockets there are on the rear wheel.
Mike Sales
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Re: Campag square taper bottom bracket

Post by Mike Sales »

There is a possibilty that your Olmo was made for the British market, with British threading.
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Valbrona
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Re: Campag square taper bottom bracket

Post by Valbrona »

If i owned a house i would bet it on an Olmo being Italian-threaded, but as per a previous post the OP could measure the width of the BB shell.

both left and right cups in an Italian-threaded frame undo counter-clockwise.

You need a special-fitting campagnolo BB tool. Beware, there are a couple of types out there. No, three types in fact!
I should coco.
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