Tomassini bottom brackets

oflahero

Hi - just wondering if anyone knew this off the top of their heads.

Thinking of replacing the BB on my Tomassini Tecno Tig (provenance: early '00s; it's got a 105 old-style square taper). I assumed it would be a 70mm Italian thread, but I read somewhere that Tomassini also produce a certain number of ISO (British thread) 68mm BB frames. I've checked the frame itself, and can't see any indication either way - and I don't trust myself measuring it, not in the 2mm margin of error anyway. Don't want to start heaving away with the BB remover only to find that I've been pushing the wrong way and have banjaxed the thread.

Any easy way to find out, or is it down to the LBS with me?

DirkVoodoo

Is there no stamping on the bottom bracket?

oflahero

The serial number's clear enough, as is the ginormous 'HANDMADE IN ITALY'. I am green enough in these matters, though - is there something obvious I should be looking for?

doozerie

If it is a sealed bottom bracket, the only markings might be on the body of it (inside the hub), but an unsealed one (and maybe some sealed ones) should have markings stamped into the face of one or both cups. But either way there should be markings on it somewhere.

I believe that both British and Italian threaded bottom brackets tighten clockwise on the left (non-drive) side. So it's just the right side that you'll have to figure out the direction of, but assuming the threads are not seized, you should be able to figure out which direction to unthread it without any risk to the frame threads as it should require a lot of force to do any damage. So I'd just give it a go if you have the right tools. Even if you only get the left side cup out, and you don't have something accurate like a vernier calipers to measure the diameter of it, you could then bring that to a bike shop for them to check which thread it uses.

As regards Italian frames and their choice of thread generally, I have a Bianchi with British thread for the bottom bracket, so it's certainly not unheard of to have that mix. In fact I read somewhere that all Bianchi's use British thread.

oflahero

Much obliged chaps.