bottom bracket question

indy335

I need a new bottom bracket for my 10 year old steel framed mountain bike. the 'hole' in the frame measures 35.5mm inside diameter. The writing on the frame is Universal, OST oversize tubing ATB frame. At the bottom of the frame it says Hand built U.K. British safety standard. BS6102 Parts 1 & 2 exclusively distribute(no d!) by UNIVERSAL CYCLES PLC RAYLE(no i)GH ESSEX UK. (does the misspelling mean it was made out of the country??)
I have tried a shimano BB-UN53, the width seems OK but the thread diameter was slightly too small for the thread on the bike.
thanks for help.

alfeng

HMMmm. Well, there is a 0.00001% chance that the bottom bracket has an ITALIAN threading! Really ...

... I actually have two XT bottom brackets with ITALIAN threaded cups! There was a brief (really brief) moment in time when some mountain bikes were made with Italian threaded bottom brackets.

If the bottom bracket shell is only 70mm wide and/or both cups are right hand thread (OR, marked 36x24), then the threading IS Italian!

I don't know what the Spanish threading is ... but, that is for BMX bikes, and should not be a concern.

indy335

If the bottom bracket shell is only 70mm wide and/or both cups are right hand thread (OR, marked 36x24), then the threading IS Italian!

reply:
the bottom bracket shell (the width of the housing on the bike with the BB removed) is 70mm and both threads are right handed - I guess that makes it an italian BB no?

alfeng

Hard to imagine anything else, right now ...

To state the obvious, you may be really limited in the choice of replacement bottom brackets ... particularly if you want to use your current crank which I presume has a square taper.

FWIW. XTR Octalink fits on Shimano ROAD Octalink BBs, and vice-versa ... a 109.5 ROAD Octalink BB works well with a steel frame. The XT Octalink has a slightly different diameter.

You can certainly find Italian threaded bottom brackets on eBay ... just be patient otherwise you'll probably pay top dollar ...