Bicycle Mechanics - Backwards BB

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
trek330
04-16-12, 03:09 PM
I just received a frame in the mail with a Campy Record BB.I noticed left side was on the right and the right side was on the left.(Sides are marked)Installed backwards!!I asked the seller and he said yeah it was installed backwards and had been ridden that way for 3 years and rode fine.Could it be??
ivan_yulaev
04-16-12, 03:19 PM
If it's an italian BB, I guess. English, well, it should work fine, as long as you never have to take the BB apart :-P
cny-bikeman
04-16-12, 03:27 PM
Only possible with Italian threading. Assuming you just mean the cups were reversed there should not be a problem, but traditional cups would have a shoulder for the fixed cup to be locked against the bb face and lockring to lock the adjustable cup, which would be more than a bit awkward when you need to adjust the bb. I think we need a bit more detail or a pic.
bobotech
04-16-12, 05:24 PM
Could he just mean that the spindle was installed backwards? So the shorter end was on the drive side and the longer end was on the non-drive side?
onespeedbiker
04-16-12, 06:37 PM
What makes the most sense is someone simply installed the BB backwards. Since a number of Campy BB are symmetrical, the chain line should not be a problem. My only concern would be getting the drive side tight enough as it is no longer the fixed side. If it was me I would R&R the BB and mount it the right way; but that's just me and I have the tools.
HillRider
04-16-12, 06:56 PM
Is this a cup-and-cone or a cartridge type bb? For either one reversing the cups would work assuming the threading is Italian.
trek330
04-16-12, 06:57 PM
http://i1183.photobucket.com/albums/x470/Donaldsos/DSC_0140.jpg http://i1183.photobucket.com/albums/x470/Donaldsos/DSC_0139.jpg Notice the threads showing.on the drive side(it says left)Should that have a lock ring on it or something?The non drive side is flush.
trek330
04-16-12, 06:58 PM
By the way this is a 1989 Pinarello Montello frame.
HillRider
04-16-12, 07:03 PM
The threading is Italian (36 mmx24tpi) as engraved on the cup.
trek330
04-17-12, 05:51 AM
Please notice the exposed threads on the Driveside.(the original left)Should there be a lockring or something there?
HillRider
04-17-12, 07:45 AM
Please notice the exposed threads on the Driveside.(the original left)Should there be a lockring or something there?
There certainly should be a lock ring on the adjustable cup side and it should be on the non-drive side for access. I'd turn that bb around.
Could it just mean thread direction? My mtb was marked L on the drive side and R on the other/but it was a cartridge bb.
Bill Kapaun
04-17-12, 03:37 PM
Could it just mean thread direction? My mtb was marked L on the drive side and R on the other/but it was a cartridge bb.
And it also had opposite threads on the opposing sides, so it only goes in one way.
Italian has the same thread on both sides.
... he said yeah it was installed backwards and had been ridden that way for 3 years and rode fine. Could it be??
He rode it for 3 years without a lockring??
Isn't that a cartridge BB? If not, what's the 102mm mean?
Drew Eckhardt
04-17-12, 07:37 PM
Please notice the exposed threads on the Driveside.(the original left)Should there be a lockring or something there?
No - it's a cartridge bottom bracket.
Your Campagnolo cassette tool will work on it.
HillRider
04-17-12, 07:45 PM
No - it's a cartridge bottom bracket.
Your Campagnolo cassette tool will work on it.
Looking again, I believe you are right, it is a cartridge, but why all the exposed threads on the one side? I have a Campy Chorus square taper cartridge bb in one bike (English threaded) and both cups thread in all the way. The ds cup has a flange that tightens against the bb shell and the nds cup threads in completely with no exposed threads. I wonder if someone "faced" the bb shell on the OP's bike too agressively and narrowed it.
trek330
04-17-12, 08:15 PM
Looking again, I believe you are right, it is a cartridge, but why all the exposed threads on the one side? I have a Campy Chorus square taper cartridge bb in one bike (English threaded) and both cups thread in all the way. The ds cup has a flange that tightens against the bb shell and the nds cup threads in completely with no exposed threads. I wonder if someone "faced" the bb shell on the OP's bike too agressively and narrowed it.
what would the proper measure be?
onespeedbiker
04-17-12, 11:54 PM
The BB shell should be 70mm wide
trek330
04-18-12, 08:49 AM
The BB shell should be 70mm wide
I measured 69.6mm.
Can you see whether that bit of exposed threading is in fact RH thread (as per Italian standard), and not LH thread as jules suggested?
onespeedbiker
04-18-12, 11:26 AM
Can you see whether that bit of exposed threading is in fact RH thread (as per Italian standard), and not LH thread as jules suggested?I have several campy BB and the Left and Right are directional, not for threads. If you look at the adjustable side (with the threads showing) you can see that it marked 36x24t for Italian threads (actually both sides are marked as Italian); by definition Italian threads are right hand thread on both sides..
Right, we're all agreed on what the standard is. But there's something non-standard here. The most likely thing by far is that it's just a non-standard installation, as everyone has said. But there's one thing that would really clinch it, and that's seeing the direction of that exposed thread. And how hard is it to look?
A minor point, but neither side of the cartridge is actually marked "Italian," as everyone keeps saying. They're marked "36x24T," and certainly you can infer from that that they have standard Italian thread direction. But you could also infer that my Bianchi has standard Italian threading, since the cups had no markings and the shell is 70mm wide; and in that case you'd be wrong. It's I.S.O. (1.370x24 RH/LH).
onespeedbiker
04-18-12, 04:17 PM
A minor point, but neither side of the cartridge is actually marked "Italian," as everyone keeps saying. They're marked "36x24T," and certainly you can infer from that that they have standard Italian thread direction. But you could also infer that my Bianchi has standard Italian threading, since the cups had no markings and the shell is 70mm wide; and in that case you'd be wrong. It's I.S.O. (1.370x24 RH/LH).There are a few 70mm shells that use English threads; that's a known quantity. One describes 36x24T as Italian, without the 36x24T you could be talking about a Fiat. Further the only BB cups that are marked 36x24T have right hand threads on both sides (Besides what's in a name? That which we call a rose by any other name would smell as sweet; sorry it was just too apropos to pass up). It would be like asking if your 1.370x24 cups might also have right hand threads on both sides; they don't because that configuration does not exist.
However, one is still stuck with the OP issue. At this point my only guess is that installing it backwards obviuosly will work. This king of BB installed does not use a lockring, so it appears there is something about mounting it backwards that causes the adjustable locking cup to sit more outboard on the right side than normal.
onespeedbiker
04-18-12, 09:08 PM
I measured 69.6mm.That is within tolerances for an Italian shell.
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.