Inner Tube Sizing - does it matter?

[CopperCyclist]

I ask because I have some 25/35 tubes left from when I used to run 28mm tyres. I now run 35mm - now, obviously as its marked up for a maximum of 35mm, the 25/35 tube will fit it... but... is it recommended? Is it actually better to fit at the top end of the inner tube range, or the bottom (I.e. would the 25/35 tube fit a 25mm tyre better, or a 35mm) Or, finally, is it better for your wheel to sit in the middle of the range?

 

[mcshroom]

Getting a bigger tube into a narrower tyre can be difficult because of all the extra rubber. Putting smaller tubes in wider tyres is supposed to make them slightly more puncture prone due to streching them thinner, but in practice I do this a lot without any problems.

 

[I like Skol]

You are within the spec so stop worrying and use it/them. Lifes complicated enough without over thinking things like this

 

[MrJamie]

I wondered the same, i noticed some companies make tubes that cover a huge range where as others are much more precise. IIRC some of the Schwalbe ones are like 38-42mm while I think some of the others are more like 28-40.

 

[CopperCyclist]

You are within the spec so stop worrying and use it/them. Lifes complicated enough without over thinking things like this

I'm not worried more wondering whether I'd be better of buying replacements of the same, or ones where I'm mid range.

 

[GrasB]

It's best to buy tubes which can be installed on the smallest tyres you're likely to put on the bike. As said before oversizing a tube leads to issues due to if folding inside the tyre. Oversizing a tube tends to allow for more punctures but that only really applies to very thin racing tyres with little to no puncture protection, at >35c I doubt that would apply, even a Schwalbe Kojak, which is very light weight & offers low puncture protection for a touring tyre, is thick compared to a proper racing tyre.