wrong size inner tube

[mjr]

Whatever it was, it was too big!

27x1¼" then. It's crazy we ended up with fractions and decimals meaning different tyre sizes - I expect some people end up with wrong tubes that way. More commonly getting 26x fraction (vintage and small-wheeled road/hybrids) and 26x decimal (MTB) muddled.

 

[youngoldbloke]

My Orbea came from the factory with 23-25 mm inner tubes inside 28mm tyres. I suspect there's quite a lot of leeway in tube sizes, and 2 or 3 mm on the diameter makes very little difference to the way the tube performs.

 

[Threevok]

I once gave a stranded 29'er a 26 inch tube.

It got him home, plus he returned it to me the next time I passed him.

I later gave the same tube to another stricken cyclist, this time riding 26'er

I never saw him again though

Should I be worried ?

 

[DCBassman]

27x1¼" then. It's crazy we ended up with fractions and decimals meaning different tyre sizes - I expect some people end up with wrong tubes that way. More commonly getting 26x fraction (vintage and small-wheeled road/hybrids) and 26x decimal (MTB) muddled.

I've personally fallen foul of the 26" conundrum. Was my first tyre purchase of the 'modern' era, ie post-1970...

 

[Dogtrousers]

My Orbea came from the factory with 23-25 mm inner tubes inside 28mm tyres. I suspect there's quite a lot of leeway in tube sizes, and 2 or 3 mm on the diameter makes very little difference to the way the tube performs.

When I blow up a tube to test a repair they can get pretty ginormous. So I agree that a couple of mm too small is unlikely to make a fat lot of difference.

 

[Blue Hills]

When I blow up a tube to test a repair they can get pretty ginormous. So I agree that a couple of mm too small is unlikely to make a fat lot of difference.

Me too - so yes would run fine I think - but if the tube is nominally smaller than intended for the tyre couldn't its "over" inflation be stretching the rubber too much/making it more likely to fail early?

 

[Dogtrousers]

Me too - so yes would run fine I think - but if the tube is nominally smaller than intended for the tyre couldn't its "over" inflation be stretching the rubber too much/making it more likely to fail early?

Maybe, but I think it's unlikely enough not to worry about. Not that I'm a material scientist or anything, I just think 2mm for a stretchy thing is no big deal.

That doesn't mean I actively advocate using undersized tubes. I buy the ones that match my tyre size, it's only sensible. But if I end up with a tube that's a bit small or a bit big - within reason - I'm not going to stress about it.

 

[SkipdiverJohn]

It's crazy we ended up with fractions and decimals meaning different tyre sizes - I expect some people end up with wrong tubes that way. More commonly getting 26x fraction (vintage and small-wheeled road/hybrids) and 26x decimal (MTB) muddled.

Some people even manage to get mixed up with fractional 26" sizes. I was given a couple of 26" x 1 3/8" roadster tyres, by the seller of one of my secondhand acquisitions. He actually needed 26" x 1 1/4", the same size that my old Raleigh Arena "racer" was equipped with, but unfortunately thought that 26" x 1 3/8" was "only one-eighth of an inch wider so they will fit OK " What he didn't take into account is that 26" road rims are 1/4" larger diameter than 26" 3-speed roadster ones......

 

[classic33]

When I blow up a tube to test a repair they can get pretty ginormous. So I agree that a couple of mm too small is unlikely to make a fat lot of difference.

Inflate one, outside of the tyre, to around the 10 foot mark. They can stretch a fair bit more than 1 or 2mm.

 

[silva]

I'd say the more/bigger inflated the less thick they'll be, leaking more/quicker air, and the more frequent you'll need to repressure them.