Question re: tube size

[Willy]

I find that I have a number of Kendra 700x18/23C tubes and now running Michelin Pro4 25c tires. What do you think, can I use the tubes with my tires?

[vqdriver]

butyl? yep

[djg21]

I find that I have a number of Kendra 700x18/23C tubes and now running Michelin Pro4 25c tires. What do you think, can I use the tubes with my tires?

Yes. They will expand to fill the tire.

[buddybikes]

I use 18's in 28's...just because I had them and too lazy to buy new ones

[veggieburger]

Oh ya, no probs.

[Cicli]

I got new tires for my mountain bike. When I changed them I discovered a road tube in the rear. Was in there for over a year. No issue. 18-23 in a 2.2 tire.
I cary a road tube on the mountain bike seat oack becaues it is wayyyy smaller than a mountain tube and will get me out of a bind. Myst have forgot about it being in there. :banana:

[Ken Robb]

The more you stretch a tube the faster it will lose air but not enough to really matter assuming you check your tire pressure every couple of days if not before every ride.

[dddd]

The effect of a more-stretched inner tube is that any sort of puncture results in the hole being more stretched open, so results in much faster air loss.

Also, when a relatively wide tire is mounted on a narrow rim, a larger tube cross-section prevents the familiar problem of the thickened rubber adjacent to the valve stem from failing to settle in the rim cavity with resultant tube rupture to either side of the rubber pad.

I've seen standard road tubes used in 1-1/4" tires with what I would call a very high rate of failure from overstretch. Putting a road tube in a 2" tire seems most likely to be completely unreliable, as the thickened rubber surrounding the valve stem forces all of the stretching into the thinner portion of the tube running barely more than half way around it's relaxed diameter.

Tubes have printed sizes that often only vaguely reflect their actual relaxed size. So I measure tubes width while deflated and pressed flat, which is in the range of 22-26mm for standard road tubes. I've used hybrid-width tubes that measure 30mm flat, and which then fit into 23mm tires with no creases.

Pinch-flatting squeezes rubber away from the center of the point of impact, which causes a tube to fail in tension. Using a tube that is highly tensioned as fitted thus reduces any margin of tolerance of the tire bottoming against the rim.

[carpediemracing]

I have no explanation why but I tried smaller tubes in larger tires as a way to trim costs (didn't have right size tube) and to save weight.

I have flats much quicker when doing this. Normally I barely flat at all, only at end of tire life (when debris worms its way through the casing) but with the small tube experiences I pinch flatted pretty much every single time I tried it. I do know how to install a tire/tube also; as evidence I've installed hundreds if not thousands of tubes over the course of my life (bike shop about 15 years, plus my own personal tires/wheels)

I tried it mainly with mtb tubes because I have never really run wide 700c tires in anything. So I was doing 1.5-1.75 or 1.5-2.1 tubes in 2.35 or 2.2 (instead of 1.9-2.2 tubes). I also tried some super skinny road tubes (19c?) in 23c. All butyl. I tried this a few times over maybe 6-10 years, sort of like my attempt to go back to 170 cranks over about a 15 year period (went to 175s in 2003, tried to go back 2008, 2011, 2016).

To be sure going to a "wider than tire" tube is also bad, so trying to jam a 1.9-2.2 tube into a 1.75 tire isn't good. Tube folds over, very easy to end up with bead over tube, etc.

My 100% failure rate with the undersize tubes made me stop the experiments. For example the only wide tire road bike we have is a tandem with 32c tires. I got the widest proper size tube as spares - not going to carry around some 19-23c tube.

[oldpotatoe]

I find that I have a number of Kendra 700x18/23C tubes and now running Michelin Pro4 25c tires. What do you think, can I use the tubes with my tires?

Sure..you can always use a smaller tube than tire size with the understanding that it will be a little bit thinner when inflated...inflate a tube outside of a tire..slowly..see, it becomes ginormous.

I know a guy(true story)..who still uses tubes in his 29er and carries 26 inch, thin tubes cuz they are 'lighter'...