Does inner tube really matter? — BikeRadar
Road cycling forum
Does inner tube really matter?
edited October 2011
Just a quickie!
Does it really matter if you fit a 700x35 inntube into a 700x25 tyre?
Im guessing it would if it was the other way round, but does it really make a difference?
I doubt you could put a 35 tube into a 25 tyre, if you can, I would expect it is likely to get caught between the tyre and the rim at some point.
Even fitting a 25 tube to a 35 tyre is likely to cause some issues, and although it will work (I have done it as a temporary repair a couple of times), the butyl is likely to be strengthed thinner, and possibly more likely to puncture.
It can be done, but only for extreme emergency.
There is no way you'd be able to get pressure up with a 35mm into a 25mm tyre. The 35mm is almost the same as a mountain bike inner. In the inner would crease or twist inside the tyre wall.
Putting a 25mm inner into a 35mm tyre would expand it way too much and at 100 psi could explode if you hit a pot hole.
Kona Jake the Snake
Merlin Malt 4
It will be fine either way. It's the tyre carcass that takes all the stress, the innertube is just an air tight bladder, a 35mm just won't get stretched inside the tyre.
2010 Cube Agree SL
The smaller tube will struggle to fill the bigger tyre; you'll get low spots that you'll be able to feel as the wheel goes round.
With the big tube in the small tyre, you'll get bunching of the tube within the tyre; again you'll be able to feel it as the tyre will not be able to deflect as much in these areas so you'll get high spots on the wheel.
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