Is this right? strange bottom bracket issues..

[Magpiegifts]

Re: Re:

edit seen the other pic.

other than the wrong cap.is off for fitting that looks fine.

take the other cap of and push the drive side one on fully. I would make fitting easier.

Just to clarify I had real trouble putting the BB in and tightening it at first..the left side would tighten up but then the right side cap wasn`t flush with frame. So the last ime I put it in from left to right but fully tightened up the drive side first until the cap was flush with the frame..then tightened up the left side. The left side would keep going in and in the frame until it tightened up.
I rode it the other day and the BB does seem to be fine. My issue is that the spindle length is not symmetrical/equal on both sides..it does seem to be much longer on the right side. Is that something that you have come across? I can`t get the first gear at all at the moment but then the barrel adjuster is broken completely. Maybe fitting the new RD may make a difference?

Some bottom brackets have unequal lengths of spindle either side of the bb. One side is offset against the other. Longer on the driveside I believe.

 

[benjabbi]

Yes, the BB shell is the bit of frame the BB screws into, measure the width it'll be 68 or 73mm, you need a corresponding BB. A 68mm BB in a 73 shell will put the BB off centre in the frame.

 

[LeePrice]

Yes, the BB shell is the bit of frame the BB screws into, measure the width it'll be 68 or 73mm, you need a corresponding BB. A 68mm BB in a 73 shell will put the BB off centre in the frame.

ok..thank you...I`ll check that now. I`m assuming if it`s the wrong size it will really mess up my gearing?

 

[LeePrice]

Yes, the BB shell is the bit of frame the BB screws into, measure the width it'll be 68 or 73mm, you need a corresponding BB. A 68mm BB in a 73 shell will put the BB off centre in the frame.

Banjabbi...well the BB is 68mm and the BB shell is 70mm....in your opinion is that a problem?...the same guy who sold me the frame also sold me the BB and gave me the chainset so I assumed they`d all be ok. He did give me the wrong size front derailleur initially though..

 

[benjabbi]

70mm doesn't sound right! Italian BB road frames are 70mm but also have dual right hand threaded cups.
It'll move the chainline out 2.5mm, there should be enough adjustment in the front mech to cope and that small a difference in chainline shouldn't really affect the rear gears at all.

 

[LeePrice]

70mm doesn't sound right! Italian BB road frames are 70mm but also have dual right hand threaded cups.
It'll move the chainline out 2.5mm, there should be enough adjustment in the front mech to cope and that small a difference in chainline shouldn't really affect the rear gears at all.

No...the actual frame width is 70mm excluding the cup wall thickness that`s flush against the frame on the drive side..

The front mech is working very well...I`m waiting for a new RD to see how that is..

 

[FluffyChicken]

Re:

Just realised you've mentioned the frame, trek 950 1993?

Thatakes things easier, shell.is 73mm (the bit I was asking you to measure before).
You need the correct size bottom bracket.
A 73 mm shell on these is actually just a cup replacement if you are lucky, the 73 shell would sit it 2.5mm further to the left from memory (the cups are thicker).

 

[LeePrice]

Re: Re:

Just realised you've mentioned the frame, trek 950 1993?

Thatakes things easier, shell.is 73mm (the bit I was asking you to measure before).
You need the correct size bottom bracket.
A 73 mm shell on these is actually just a cup replacement if you are lucky, the 73 shell would sit it 2.5mm further to the left from memory (the cups are thicker).

Hya..I think it`s a 94 or 95 model as it has TIG welding not lugged joints. I`m pretty sure I measured the actual shell correctly at 70mm...it may be closer to 73 including the tighten cup that lies flush against it on the right side.

I`m not really understanding about the cup replacement?...where would I get one of those...and would that mean replacing the cups on both sides of the BB.

I`m not sure how to move forward in getting everything right. I was told I needed a BB to match the chainset. Now it seems I have to get a BB to match the frame shell..then find a matching chainset for the BB length? Are you saying I have been supplied the incorrect size BB for this bike at 68mm and it should have been 73mm really?

Thank you.

Lee

 

[benjabbi]

The length is right for the chainset at 122.5mm however the shell is the wrong size. You need a 73x122.5mm BB
What Fluffychicken said is in relation to a UN-71/2 BB, the actual cartridge is the same it just has different width cups to account for the difference in shell width. I doubt you'll find the cups on their own, but if the one you end up buying is rougher than the one you have, you can swap the cups to the better cartridge.

 

[LeePrice]

The length is right for the chainset at 122.5mm however the shell is the wrong size. You need a 73x122.5mm BB
What Fluffychicken said is in relation to a UN-71/2 BB, the actual cartridge is the same it just has different width cups to account for the difference in shell width. I doubt you'll find the cups on their own, but if the one you end up buying is rougher than the one you have, you can swap the cups to the better cartridge.

Thank you...is it possible to get a 73x122.5mm BB these days? I was thinking a UN55 was a suitable replacement but it seems to be Italien threaded (I guess that`s not right) and I can`t find one in the correct size..