Tube size vs tyre size

Question- I have a 28c tyre, I have a 23c small tube, and a larger 28-30c+ CX tube. I don’t have a perfect ‘28c tube’.

What is better- use the smaller tube and have it stretch out more, or use the CX tube and hopefully not have it ‘wrinkle’ inside?


either will work fine, have done it heaps.

The 28-32 tube is actually designed for 28c tyres.

edit: actually I think the tubes in my 28c tyres are probably 28-35’s and maybe some 25-32’s in my 42c tyres.


I use a 19-25mm tube in a 28c Rando with no problems at all.

Use the larger tube.

The smaller tube will work but will be more likely to flat as it will be stretched thinner.

But you never flat, right?

always smaller to upset blakey

Just run tubs.

Thanks, that was my initial thinking.
One problem I found with the bigger tubes is they tend to wrinkle inside, as though the tube is a slightly bigger diameter than the tyre- what’s that about?