British or Italian thread on a stuck bottom bracket?

Hi all,

So I’m finally getting round to doing some work on an old Simoncini track bike I bought on here years ago and I’m having trouble removing the bottom bracket!

It’s a sealed bearing uni and I’ve removed the plastic cup on the drive side however the left side is proving tough to come out. I’ve been very tentative so far. Not used a breaker bar or any force more than I can muster myself but it doesn’t want to budge.

My concern is, is it British or Italian threaded? My understanding is that Italian is clockwise on both sides? I don’t want to go put in loads of force in the wrong direction.

Is there any way to tell what style threading I have? And any advice as to which direction to try unthreading the left side? I was gunna start with a breaker bar and go from there. For now I’ve soaked it in GT85 and will try some new tactics this evening.

Cheers

AFAIK, Italian BB shells are 70mm wide and British 68mm.

I know two people with Simoncinis one 70's road bike and one 90's track bike and both have confirmed Italian BB's on theirs

Okay, I’ll give this measurement a go!

Good to know, thank you. It’d make sense for them to be Italian threads I guess. Thinking about it if Italian threads are clockwise on both sides, British left hand bb threads are clockwise anyway so regardless of thread type the left should undo the same direction I guess. I think my logic is correct here?

Yeah left side threads are the same for both ITA and BSA. Good luck with it

Interestingly enough it’s 68mm so who knows!

Well, you do because you've already taken the drive side off.

I own a Simoncini track bike and can confirm its Italian BB. Good Luck! Post a pic of your bike if you get a chance

Strange that the width is 68mm though! I guess I’ll just have to remove it and try a bb and see what fits!

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Beauty! Whats Columbus steel is it, I’ve not got a sticker on mine and there’s not much on the internet about Cinis

Cromor! It’s got a few quirks as I’m finding. A somewhat seized bottom bracket, and something weird going on with the seatpost clamp. The gap where the bolt tightens was filled with metal so I’ve effectively had to recut that. Still unsure of the seat post diameter… I had a 26.6 knocking about and that’s close but doesn’t quite get tight enough. I’m thinking 26.8. I hear that was somewhat popular with Italian frames.

Also despite everyone saying their Simoncini’s are Italian threaded bottom brackets I’ve just confirmed mine is British! The drive side cup, which I’ve removed, threads in counterclockwise…

It’s a sealed bearing uni and I’ve removed the plastic cup on the drive side

Is it plastic both sides or metal on the nds?

Metal on the nds and plastic ds would suggest it was the wrong way around to me.

Hmm good point! It was plastic drive side and metal nds.

That also suggests that it is Italian thread because with a British thread, you wouldn’t be able to screw it in the wrong way round.

The plot thickens! I’ll see if I can get the nds free this weekend and we’ll go from there.

Still confused as to why the shell diameter is 68 though…

Shell width.

There is of course also a difference in diameter which could be used to identify what you have.

Its not a big difference though so you’d need to be pretty accurate with your measurements, 34.8mm for English iso and 36mm for Italian.

Ah yes sorry getting my terminology mixed up! Okay, that’ll be the next measurement to make. Cheers

Edit:
Cursory glance at the plastic cup with the tape measure looks like 34.8 but I’ll double check with some callipers at the weekend.

Hmm, the left hand thread has me stumped.

I’ve heard it suggested that you can cut an Italian thread into a shell with a damaged English thread but I don’t know of anyone that’s actually done it or how you’re meant to account for the difference in width.

Doesn’t sound like this is what you have with the drive side thread being left handed.

Did the plastic cup unscrew fairly easily and what condition were the threads in? I wonder how easy it’d be to force a right hand threaded plastic cup into a left handed threaded shell, pretty much recutting the threads in the plastic as you went? I would expect the threads to look pretty messed up if this had happened .

Forcing the plastic cup into the wrong side would be one thing though, performing the inverse trick with the metal cup would need a pretty impressive level of mechanical ineptitude.

Plastic cup came away easily, threads are fine can thread it back in by hand so doesn’t seem to be damaged at all.

Everything seems to be pointing to an English thread bb in my opinion. Could it be a restickered frame? Though Simoncini isn’t a builder I’d imagine people going to the effort of rebranding!

Some Shimano BBs have the resin cup on the drive side...eg this BB-LP25
If you have a 68mm shell and the DS screws in anticlockwise then you have an English BB!👍

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I’ve just stumbled across this bike, it’s the only example of a Simoncini I could find that resembles my frame. Very similar lugs and the only example I’ve found with the Zeus dropouts.

It also lead me to a number 1 stamped on the bottom bracket shell that I’ve never noticed before!

https://www.ebay.com/itm/196008180260

@M_V

I’ve reached out to them to see if they know what thread they have…

I usually put the BB tool in a vice and turn the frame if your east I have all this if you need help
K

With the help of a breaker bar and 2 days soaking in GT85 the bottom bracket has been removed!

And can confirm that it’s British thread. It’s a Shimano LP20 68 1.37x24 bottom bracket which weighs a tonne.

Problem solved I guess!

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