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How Important is Inner Tube Size?(4 posts)

How Important is Inner Tube Size?chbarr
Dec 29, 2002 4:07 PM
Hi!

Today, I bought three tubes from a bike store. I thought I knew my tire size, however, the gentleman at the bike store convinced me otherwise. I was right.

In any case, I have a 700x25c bike, but a 700x23c inner tube. Since I only plan to ride stationary this evening, I didn't think it would make a difference today (all I really want from the tire is to keep the front wheel from buckling under). However, on the road, is this a big deal? Put another way, is this something I need to replace strait away, or simply return the extra tubes for the correct size, and live with the wrong one until I need to replace it?

Thanks,
iCharles
re: How Important is Inner Tube Size?Rusty Coggs
Dec 29, 2002 6:04 PM
It really does not matter.There is no absolute standardization ot tire sizes, and tubes stretch.Many tubes are sized and marked as usable in a range of tire sizes.
Too small is not important, too big can beKerry Irons
Dec 29, 2002 6:17 PM
The tube will stretch out to fill the tire space no mattter what size. If you use a very small tube in a very large tire, the tube will lose air faster because it is stretched thin. This means you have to pump more often, and there is a SLIGHT decrease in puncture resistance. A 23 in a 25 is meaningless - your LBS guy was right. Typically there are only three tube sizes anyway: 18-23, 20-25, and 25-32, or something like that. However, if you try to stuff one of the larger tubes into a very small tire, you run the risk that the tube will bunch up. IOW, the uninflated tube should be smaller than the tire, so it stretches at least a little when pumped up.
Kerry is right about this one...crosscut
Dec 29, 2002 9:11 PM
If you inflate a tube outside of the tire, you will see that it swells up more than enough to not worry about the difference between a 23 and 25. With a larger tube going into a very skinny tire, however, you have a problem of cramming all of that material into a limited space. In your case, don't worry about it and just ride!