[JaredP91]

So in the past week I’ve had the unfortunate experience of two punctures, leading to a requirement for some extra spare inner tubes.

The inner tubes on my Boardman before the puncture/s were 700/23/25c, but I’m a bit confused re: sizing and the numbers.

Ordered two replacement Bontrager Standard 700 x 23-25c inner tubes, however, they sent me 700 x 20-25c ones. Will these still fit?

Topic

[hawkinspeter]

Yes – they’re fine.

Yes – they’re fine.

With inner tubes, you can get away with slightly wrong sized tubes (e.g. 20-25c will stretch to fit 28c easily and maybe bigger depending on your luck). If the tubes are smaller than they should be then they’ll expand to fit, but may puncture more easily. If the tubes are bigger than they should be, then you may struggle to stuff them into your tyres.

The 700 number is the size of the wheel (which for some arcane reason means a diameter of 622mm) is confusingly the same size as 29inch MTB wheels. The 20/23/25 are different width of tyres.

[Simon E]

Yes, they will be fine.

Yes, they will be fine.

Tubes for 700 wheels and tyres are generally divided in to those for narrower (e.g. 20-25 or 20-28mm) and wider tyres (e.g. 28-40mm).

To add to the confusion, you may also see the ETRTO size for 700 wheels is 622, so a 28mm wide tyre is also specified as 28-622.

I’d recommend getting some Rema TipTop cement and F0 (16mm) patches from a shop or ebay. Glueless patches such as the ones from Park Tool are tiny and a handy to take with you.

[Author]

Replies