I just bought an old (1974 ish) Peugeot bike for my daughter. It’s lovely. However, it needs a new front inner tube (and at some point it’ll need new tyres no doubt).

I popped into my LBS earlier to see if they had anything in stock, but sadly they didn’t. I have a few more shops to try, but thought I’d test the knowledge of STW until I manage to ring around.

I attach a photo of the bike and a close-up of the front tyre. The figures read:-

37-490 (550 38A)

Can anyone fill me in on where I might get the right size tubes for these? Amazon is ideal, particularly if there is something with next-day delivery as I was hoping to go out for a bike ride this weekend with my daughter on her new steed.

A 24″ x 1.5″ tube will fit if it’s a 550mm BSD, if it’s 490mm is might be closer to 22″. LBS or decathlon should have something.

https://www.sheldonbrown.com/tire-sizing.html Sheldon doesn’t list it so it really must be niche!

I found that website too but struggled to see the exact same numbers. There is a table half way down the page that lists ISO sizes, and in there, I can see a 490mm 550A tyre, but not really sure if that’s the same thing.

I don’t really understand the two sets of figures on the tyre wall. 490 is very different to 550.

Those rims….I remember riding bikes with rims like that. Awful things if you ever want to stop.

Don’t go out in the rain without checking your dental insurance first.

Haha. They do look very shiny!

Still, we won’t be riding anywhere if I can’t get a darn tube!

I found that website too but struggled to see the exact same numbers. There is a table half way down the page that lists ISO sizes, and in there, I can see a 490mm 550A tyre, but not really sure if that’s the same thing.

I don’t really understand the two sets of figures on the tyre wall. 490 is very different to 550.

I didn’t scroll down that far, 490 will be the rim diameter, 550 will be the approximate outer diameter (in the same way 700 used to be nominally what road bikes were). A/B/C I think referred to the width of the rim, so 700c was a skinny rim, 550A was a chunky rim, but 550c would be the same outer diameter (i.e fit in the same frame) but a bigger diameter rim with a skinny tyre.

I’m amazed that the bike shop didn’t just whip out a tape measure and sell you the closest, common sized tube.

Anyhow, for future reference, it looks like St John Street cycles have a small range of tyres.

A Schwalbe AV8 will fit. I have one in my hand. If you can’t find one somewhere drop me a DM.

Thanks simondbarnes. I’ve just found one of those on Amazon so I have ordered and will hopefully get it tomorrow!

Cheers.

If it is like a lot of other old French bikes, even ones originally sold in the UK. It will probably have French size threads, instead of British sizes.
M14 pedal thread instead of 9/16″ x 20 tpi .
M25 x 1 headset instead of 25,4 x 24tpi.
M35 x 1 bottom bracket instead of 1 3/8″ x 24 tpi, and right hand thread both sides.
Plus the handle bar stem will be 22mm instead of 7/8″ fit into the steerer tube.