GB Stem: Clamp size?

[pistolpedro]

Hi guys

picked upa bike recently which has a GB stem fitted (pic below) I think the bike dates from the mid 70's i'm guessing the stem is original to the bike

Can anyone tell me what size clamp this stem will have?

I have just bought some 25.4 bars and i'd really like to use this stem with them

pete

 

[Old Ned]

These were made in the days before millimetres were invented. It is probably 1" so therefore 25.4mm could be OK.

Not sure when GB stopped making these but 70's seems a bit late for it to be original equipment.

What diameter are the 'bars already fitted into it?

 

[one-eyed_jim]

Agreed - one inch for the clamp, and probably 1960s manufacture.