Help identifying bottom bracket

So I feel like a bit of plank over this; I bought a lovely Bob Jackson frame from someone on the forum way back in December, but have been too poor/busy to get it on the road. I've been sporadically collecting the necessary parts and in a fit of impatience went to Condor yesterday and finally bought everything I need to get the thing road ready with mind to set it all up today.

I bought my groupset about 3 months ago. It's a Shimano Santé with those bizarre biopace chainrings...I also picked up a Shimano BB after scrolling through lots of compatibility lists. When I came to install it today, it wouldn't fit. This is because, I've just found out, my BB shell is made for a cup and cone affair and I'd gone and bought a sealed cartridge BB.

I know next to nothing about bottom brackets. I've fitted a few in my time, but always more modern ones built for specific cranksets and it's always been easy. Now I'm faced with the problem of trying to find which BB I need to get without making myself look even more stupid by buying the wrong one.

Googling Shimano 113mm 68mm cup and cone bottom bracket unhelpfully takes me to a non existent SJS page and an eBay sale from the US which would be setting me back about £60. Am I searching the right thing? Does anyone know where I might be able to find the right thing at a sensible price?

The type of bearings shouldn't make any difference, and cup-and-cone systems are really worth avoiding. The biopace thing is just an early ovalised chainring design, the cranks just need a square taper axle to fit to, and the frame will take an IS thread 68mm bodied bb of any kind, so putting the two requirements together, a 68x113 shimano un54 should be perfect and long-lasting

The problem is that the interior diameter of the bottom bracket shell is too small for cartridge bottom brackets (or at least that's what the mechanic at my lbs was suggesting). The bb I bought would be compatible with a normal english threaded BB shell, but the one on this frame is too narrow (diameter not width) in the middle.

I'd be surprised if any Bob Jackson used anything other than standard diameter British/ISO bottom bracket shell. If you've got a friend with a spare British BB, try it.

edit - apparently Italian, French and Swiss cup diameters are larger than British. Did BJ make non-british frames? Or is it a foreign frame repainted as a BJ?

As far as I was told, it has an installment cast BB as part of a custom build, which might explain why it's not the norm. The BB I bought that doesn't fit is a Shimano UN54.

Investment-cast, you mean? That in itself is not particularly uncommon, but it's still very odd not to have a standard thread. Have you tried to fit the BB yourself, or are you just going on what the mechanic says?

French/Italian/Swiss bottom brackets are pretty uncommon and you might have a hard time finding one, plus I don't know how you'd go about finding which it is (short of finding someone that has all three available to try). If it turns out that it really does have a French/Italian/Swiss BB shell, then it's possible to have it machined, sleeved and tapped to fit a British BB (or if not, the shell can be replaced by a framebuilder).

I've also squashed a BB shell in a vice by accident (in my youth), which mightily confused me, as it too appeared to be slightly too small... perhaps the frame has been damaged?

The problem isn't the threading.

If the top on is a normal bottom bracket shell and cartridge BB, the bottom one is what mine looks like. My UN54 literally doesn't fit into the shell because of the bit in the middle. I know the threading is right because I can screw in the plastic non-drive side bit of the BB. Is there maybe a sealed cartridge BB that has a thinner middle bit? From where I'm standing that would solve my problem...

if you dont want to use a cup and cone you can get bb that use sealed bearings. there is a nice omas bb that my friend has. it would fit in your bb. he is using his but finding the same model would be ideal.
first make sure that the threading is british. it should be on a bj but who knows. then measure the bb width to make sure its 68mm

http://velobase.com/ViewComponent.aspx?ID=0866ABC4-2948-4B7C-A710-6E23B8323979&Enum=119&AbsPos=7

Oooooh, gotcha. I thought you meant the internal diameter of the threads, not of the shell itself.

Maybe it can be machined out (not sure if this would affect the strength of the frame). Or you can use any old cup/cone BB with a 113mm axle (ebay, forum etc).

there is a nice omas bb that my friend has

Is that ISO taper rather than JIS? It's not a problem, just something to take into consideration when trying to get the right axle length.

There have got to be sealed bearing BB's that don't have/need the centre tube, meaning just the axle goes through the centre part.
Have a look through velobase's list of BB's or see what hilary stone has in stock.

JIS/campag taper is the only thing you have to worry about, but shimano sante = JIS so thats pretty simple.
Any loose ball, cup type BB will fit in there I guess as that was all that was available at the time. And if properly adjusted and maintained are at least as good as a sealed unit.

They are for campagnolo replacement bb so ISO. not as big of an issue with geared bikes. The JIS crank fit closer on an ISO taper. as long as your spindle is long enough that your crank doesnt hit hte chain stay you're good. 113 JIS I would go for a 115 or 116 ISO spindle.
The great thing about the omas is that both cups are adjustable and you can remove the plastic middle part.

Is that ISO taper rather than JIS? It's not a problem, just something to take into consideration when trying to get the right axle length.

TA make a bottom bracket with no centre shell.... i think the model is 'AXIX LIGHT''

if you got on chicken cycle kit (the importers) then click on bottom brackets i think it the second bottom bracket from the bottom of the page.

it is a sealed unit and they are a good quality bracket...

they come in 2 options , 1 being a steel axle and the other being a titanium axle.

hope this helps you :)

Perfect, expensive though!

Perfect, expensive though!

correct there but probably the best one you require and certainly the most easiest to service and in the long run it will save you a few quid because it only costs of 2 bearing and about £5-10 each. :)

Any loose ball, cup type BB will fit in there I guess as that was all that was available at the time. And if properly adjusted and maintained are at least as good as a sealed unit.

Yeah! As long as you have the correct plastic sleeve in there it should keep the water out. And if you strip, clean and regrease regulary you'll be using this sort of BB for a lot longer than a sealed unit :0)

Been rocking the same BB in my Olmo for the past 7 years, have only changed the ball bearings the once.

For the sake of archiving information, I thought I'd explain how this played out.

I wasn't satisfied with the idea that I'd have to fork out £70 for a BB, so I went to Condor, Fitzrovia and even Cycle Surgery with my frame to try and get to the bottom of the problem. A guy in Fitzrovia found a Miche BB that fitted because of it's slim body but the axle was too short so I decided to call it a day and hunt for the right size online. When I got to my friends house to pick up some stuff I'd left there, he took a look at it and suggested that we might be able to MAKE room in the shell. I was feeling a bit defeatist at this point, but he took a pair of pliers to it and to my great embarrassment/relief he pulled a plastic sleeve lining the shell out of the frame. Turns out the sheath that was used with an old cup and cone BB to stop water getting into the stays was still in there, but had been covered by a layer of grease and had turned the same colour as the steel it was protecting. Two hours later I rode my finished bike home.

For the sake of archiving information, I thought I'd explain how this played out.

I wasn't satisfied with the idea that I'd have to fork out £70 for a BB, so I went to Condor, Fitzrovia and even Cycle Surgery with my frame to try and get to the bottom of the problem. A guy in Fitzrovia found a Miche BB that fitted because of it's slim body but the axle was too short so I decided to call it a day and hunt for the right size online. When I got to my friends house to pick up some stuff I'd left there, he took a look at it and suggested that we might be able to MAKE room in the shell. I was feeling a bit defeatist at this point, but he took a pair of pliers to it and to my great embarrassment/relief he pulled a plastic sleeve lining the shell out of the frame. Turns out the sheath that was used with an old cup and cone BB to stop water getting into the stays was still in there, but had been covered by a layer of grease and had turned the same colour as the steel it was protecting. Two hours later I rode my finished bike home.

good news! at least your on the rode now :)

glad it is all sorted.

well done !!