# Inner tube size advice



## AlexTheory (8 Feb 2012)

Hi all, real newb question this but I don't want to buy the wrong tubes, get a puncture and be stranded cos I have the tube for a Raleigh Chopper...

My bike is a Boardman Hybrid Comp with, as far as I know, a 700x28 wheelset.

I'm thinking that the specialized set of 700 x 28/38 (part number on Evan's website 101213-NA-NA) would be correct... but what does the '38' in this spec relate to?

Thanks in advance!


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## sdr gb (8 Feb 2012)

Hi Alex

The 38 refers to the maximum wheel size the tube will inflate to. Most inner tubes are manufactured to cover a range of wheel sizes. These tubes will fit a 28 wheel and sizes in between up to a max of 38mm.

Hope this makes sense.


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## AlexTheory (8 Feb 2012)

Thanks SDR GB, that makes sense - I'll get a couple of them ordered!


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## rollinstok (8 Feb 2012)

Hi, the 700 bit refers to your wheel size. The 28/38 refers to the tyres on the wheel, so that inner tube will do for tyres between 28 ( yours ) and 38. I personally would opt for an inner tube that has your tyre size nearer the middle of its range if at all possible..something like 700 x 25/32


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## Arjimlad (8 Feb 2012)

Also make sure the valves are long enough. Deep rim sections will need longer valves. Best to measure what is on there already.

My wife went into Halfords for me with a piece of paper on which I had written

"inner tube, 700x23, long valve suitable for Carrera TDF" .

The helpful chap in Halfords upon seeing my note selected a standard short valve length tube which does not fit the Carrera tdf wheel. I would not mind but the Carrera is a Halfords bike !


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