Off-center bottom backet

General69 · #1 10-26-2017, 08:18 PM

Anyone have this issue? I had a 3 piece bottom bracket for years but decided to get a cartridge. As you can see from the photos, it's not straight. I know it's not cross threaded since I turned it by hand. Bike is a 1982 Lotus. Thinking of just screwing in left side till it straightens.

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charliedid · #2 10-26-2017, 08:46 PM

You need to fully install it to determine anything. I'd start by facing and chasing that shell. Grease everything really well.

donevwil · #3 10-27-2017, 12:41 AM

You didn't mention what BB you installed, most cartridge BBs have a slip or light press-on drive side cup. They seem permanent, but can slip during install. Have you tried installing the non-drive cup to see if the BB rights itself and seats in each cup appropriately?

11.4 · #4 10-27-2017, 01:15 AM

Yup. They often look eccentric like that with only one side screwed in. Before you tighten it down, screw in the other side to help guide the cartridge. And as pointed out above, face and chase the shell before installing.

CiclistiCliff · #5 10-27-2017, 03:36 AM

Make sure it's not cross threaded...

Ralph · #6 10-27-2017, 06:42 AM

Never mind...misread original post.

oldpotatoe · #7 10-27-2017, 07:22 AM

Quote:

Originally Posted by charliedid

You need to fully install it to determine anything. I'd start by facing and chasing that shell. Grease everything really well.

Agree..clean up the threads, then face it..If UN70 series BB, tap off the RH cup..grease in there, tap back on..grease in LH cup..

icepick_trotsky · #8 10-27-2017, 10:44 AM

What's going on with that double bottle cage?

FriarQuade · #9 10-27-2017, 11:27 AM

If it threaded in by hand, DO NOT CHASE IT! Why people are recommending this on a 30 year old frame that was very likely done when new is baffling to me. Chase and face is something that only ever needs to be done once. Exceptions made for trying to repair a cross threaded shell. If you do chase it you only risk creating a problem with zero upside to solve one that isn't there. Even if it's well done without a hitch you're going to pull a little bit of metal off the threads which opens up the chance for a creaky bottom bracket.

Fully install the bottom bracket and then see where it sits. Bottom out the drive side then snug up the non drive and that's it. Then dry fit both crank arms and see if they are roughly centered, if that looks good then torque them down and go ride.

cmbicycles · #10 10-27-2017, 11:35 AM

Never Mind

charliedid · #11 10-27-2017, 12:21 PM

Quote:

Originally Posted by FriarQuade

If it threaded in by hand, DO NOT CHASE IT! Why people are recommending this on a 30 year old frame that was very likely done when new is baffling to me. Chase and face is something that only ever needs to be done once. Exceptions made for trying to repair a cross threaded shell. If you do chase it you only risk creating a problem with zero upside to solve one that isn't there. Even if it's well done without a hitch you're going to pull a little bit of metal off the threads which opens up the chance for a creaky bottom bracket.

Fully install the bottom bracket and then see where it sits. Bottom out the drive side then snug up the non drive and that's it. Then dry fit both crank arms and see if they are roughly centered, if that looks good then torque them down and go ride.

I don't entirely disagree with you.

charliedid · #12 10-27-2017, 12:25 PM

That said the non-drive side photo does not inspire confidence. Either way we agree that it needs to be fully installed first to determine anything.

FriarQuade · #13 10-27-2017, 10:38 PM

Quote:

Originally Posted by charliedid

That said the non-drive side photo does not inspire confidence. Either way we agree that it needs to be fully installed first to determine anything.

Those photos aren't from an angle that gives them sufficient merit. On top of that cartridge bottom brackets are largely immune from problems created by non-parallel faces. If the bike had a cup and cone bottom bracket for the first 20+ years of life it's just fine. That style of bottom bracket is what dictated facing procedures in the first place.

11.4 · #14 10-28-2017, 02:39 AM

Quote:

Originally Posted by FriarQuade

Those photos aren't from an angle that gives them sufficient merit. On top of that cartridge bottom brackets are largely immune from problems created by non-parallel faces. If the bike had a cup and cone bottom bracket for the first 20+ years of life it's just fine. That style of bottom bracket is what dictated facing procedures in the first place.

On the other hand, cartridge bottom brackets also are designed to allow for a bit of variance in width of a bottom bracket shell. And cartridge bottom brackets also can incur binding caused when the shell isn't square. When one chases and faces a bottom bracket shell that's already been used and hopefully chased and faced before, one spins the taps in and out to be sure taps are clear, and then runs the facing mills down to the shell edges and turns them by hand before cutting metal. If a shop just takes of 2-3 mm of metal for the hell of it, that shop would botch any bottom bracket installation.

charliedid · #15 10-28-2017, 08:28 AM

Quote:

Originally Posted by FriarQuade

Those photos aren't from an angle that gives them sufficient merit. On top of that cartridge bottom brackets are largely immune from problems created by non-parallel faces. If the bike had a cup and cone bottom bracket for the first 20+ years of life it's just fine. That style of bottom bracket is what dictated facing procedures in the first place.

I understand all of that, and we are both making assumptions regarding the shape of the threads and shell. We have no idea how well that frame was prepped 30 years ago.

Anyway let's hope the OP finds his way to a good bike shop. I noticed this post was his first and I am guessing he does not own any frame prep tools.