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PostPosted: Mon Feb 08, 2021 7:02 pm 
Dirt Disciple
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Joined: Sat Jul 06, 2019 4:16 pm
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Apologies if it's not a classic in the true sense, but this seemed the best place to ask.
This has a 1'' headset - the question is whether it is more likely to be ISO sizing :D .....or JIS sizing :x
If anyone could shed any light on the matter, i would be incredibly grateful.

I asked Certini and they are sure it's 1'', but unsure whether it's ISO or JIS :(


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PostPosted: Mon Feb 08, 2021 9:01 pm 
retrobike rider
retrobike rider
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Location: A wretched hive of scum and villainy...
Unlikely to be JIS on such a modern, and not Japnese, frame.
BB could well be Italian threaded, though..but that's a different story.

All the best,


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PostPosted: Mon Feb 08, 2021 9:20 pm 
Dirt Disciple
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Good news about the headset :)
Italian BB you say....i don't even know what that means :shock:
Nothing is ever straightforward :cry:


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 Post subject: Re:
PostPosted: Tue Feb 09, 2021 10:40 am 
retrobike rider
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Location: A wretched hive of scum and villainy...
Well...while the 68mm BSA/ISO threaded BB is hugely more common, the Italian threaded BB is one of the last local variations to survive. There were several others such as French and Swiss. It pretty much only turns up on Italian made bikes these days, but is incompatible with BSA (at least without some specialist workshop time).

The BSA has a 1.37" diameter thread, standard RH thread on the non-drive side, LH thread on the drive side.
The Italian BB is 36mm diameter (so very slightly larger), with a RH these on both sides.

How can you tell which you have?
Firstly, the BB shell width. 68 or 73mm for BSA, 70mm for Italian.
Also, the threading should be marked on the BB cups: 1.37" x 24tpi for BSA, 36 x 24tpi for Italian.

The Italian standard is rare, but still reasonably available, both new and retro parts, so don't worry too much.

If the BB is working fine, then it's not a problem, just something to be aware of if you are servicing it, or ever look to upgrade or replace it.

All the best.


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 Post subject: Re:
PostPosted: Tue Feb 09, 2021 10:42 am 
retrobike rider
retrobike rider
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Joined: Tue Jan 29, 2008 11:04 pm
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Location: A wretched hive of scum and villainy...
Well...while the 68mm BSA/ISO threaded BB is hugely more common, the Italian threaded BB is one of the last local variations to survive. There were several others such as French and Swiss. It pretty much only turns up on Italian made bikes these days, but is incompatible with BSA (at least without some specialist workshop time).

The BSA has a 1.37" diameter thread, standard RH thread on the non-drive side, LH thread on the drive side.
The Italian BB is 36mm diameter (so very slightly larger), with a RH these on both sides.

How can you tell which you have?
Firstly, the BB shell width. 68 or 73mm for BSA, 70mm for Italian.
Also, the threading should be marked on the BB cups: 1.37" x 24tpi for BSA, 36 x 24tpi for Italian.

The Italian standard is rare, but still reasonably available, both new and retro parts, so don't worry too much.

If the BB is working fine, then it's not a problem, just something to be aware of if you are servicing it, or ever look to upgrade or replace it.

All the best.


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PostPosted: Tue Feb 09, 2021 6:44 pm 
Dirt Disciple
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Joined: Sat Jul 06, 2019 4:16 pm
Posts: 77
Really appreciate the in-depth help.
It all sounds incredibly 'yuk' :?
I like external bottom brackets :)
And cartridge bearings - hence my hatred of JIS headsets :x
I'm going off this bike more by the second.


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 Post subject: Re:
PostPosted: Wed Feb 10, 2021 9:33 am 
retrobike rider
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Location: A wretched hive of scum and villainy...
If it does come to that, there are plenty of Italian threaded external BB cups around.

All the best,


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 Post subject: Re:
PostPosted: Thu Feb 11, 2021 10:00 pm 
Retro Guru
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Joined: Thu May 20, 2010 9:03 am
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Location: Bodmin,Cornwall.
I built many Certini’s and owned three and none had Italian bb’s.
We built one for Bob Brown who tried to break the end to end and back on it. Not sure if he succeeded.


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 Post subject: Re:
PostPosted: Thu Feb 11, 2021 10:02 pm 
Retro Guru
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Location: Bodmin,Cornwall.
Slomo.
Are you Kernow Slomo ?


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 Post subject: Re:
PostPosted: Thu Feb 11, 2021 10:03 pm 
Retro Guru
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Location: Bodmin,Cornwall.
It’s one Ian or me built down in The Cycle Centre. Sticker on seat tube.


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