NachosGrande

Is it okay to use 700c 18-23 tube in 700x25 tire? It seems that there are not many companies, if any, that produce 700 x 18-25 tubes...

ThermionicScott 

Perfectly fine.

NachosGrande

Thanks ThermionicScott! I thought I wasted $$ by purchasing 10 of 700x18-23 tubes recently.

Bill Kapaun

You may also be able to find something like 23-28.

79pmooney

If you always toss tubes after flatting and can accept maybe a few more flats, an undersized tube will work just fine. But patching and re-using an undersized tube is asking a lot from the patch and surrounding rubber since the patch will not stretch like the rubber around it.

That said, undersized tubes make for a sweet ride. I seem to have seen a lot of 20-25 tubes.

Ben

Number400

It works but in my experience I would lean a little towards underinflating rather than running max recommended pressure.

hueyhoolihan

tubes are like a good spouse. flexible.

in an emergency, i've successfully run 26" tubes in 700c tires and vice versa.

howeeee

It is not perfectly fine, it will work, for awhile, but you will have more flats. You can go online and get any tube you need. The bike shops dont carry tubes that I need. 60 mm presta valve for a 700x28 tire, but you can find them online for cheaper. I run smaller tubes all the time, when it is all I can find, but without exaggeration I had about 25 flats last season lol.

leob1

Put it on, inflate and ride as you would any other tire.
You'll never notice a difference.

ragtoplvr

I have 28's but my underseat bag will not hold 2- 28-32 tubes, and the patch kit, multi tool, tire irons. It will hold one 23 tube and one 28. I have had to use the 23 tube a few times. It worked fine.

Rod

zacster

I've used undersized tubes on my commuter and they didn't last very long. But 25 vs. 23 shouldn't be a problem. I tried putting a 26x1.5 into a 26x2.1 tire and that wouldn't even inflate. It was only in an effort to get someone going again on the road. Young and very cute. (I've helped out a lot of guys too over the years...)

lopek77

I'm using little "undersized" tubes in each of my bikes. They weight much less, and perform the same way as "regular" ones. Tubes can stretch A LOT. I pumped up one (700×18-23) to see at what point it will fail. It didnt... I could ride my bike in the middle of it - it was so huge. I use Performance Bike brand tubes.
Cover new tubes in talcum/talc, or even in corn starch before mounting it for easy and pain free fit. I believe it will also keep them in a good shape for longer.

D1andonlyDman

Here's my question: How does the tube know if you're using it in a 25mm tire that actually runs small, or a 23mm tire that actually runs large, such that the 23mm tire is actually at least as large as the 25mm tire. Is it "perfectly fine" to use an 18-23mm tube in a rated 23mm tire that's nominally large, but not "perfectly fine" to use it in a rated 25mm tire that's nominally small? Because in the real world, tires from different brands can vary by more than 2 mm.

milkbaby

Pump up the tubes outside of a tire and you'll see why it doesn't matter. The tire is what keeps the tube from becoming 3 times it's usual size.

ThermionicScott 

25 flats in a season isn't a "tube slightly undersized" problem.

howeeee

One guy says it doesnt matter, if it doesnt matter why dont they just make one tube fits all? lol

Ok this is why it matters if you use a tube too large, you can have folds in the tube that will fail with use, also it is harder to get the beads to sit properly with too much tube.

This is why it matters if you use too small a tube, a tube is an air container, if you use a 28 x 700 tube in a 38 x 700 tire( I just did that exact thing and it failed after a couple weeks) the walls of the tube are stretched further making them thinner than what the manufacture intended, making it more likely to fail from dirt or slight imperfections in the rim liner,tire or rim.

I have 44 years tire repair experience from a wheel barrel tire to an earthmover tire you have to stand inside to repair.

howeeee

this experiment really tells the opposite , it tells why it really does matter, you are stretching the walls beyond what the manufacture intended, making the walls of the tube thinner and weaker than intended

hairnet

I rode with a 650c tube in my 700c(I had to get home, you know) and I never took it out because it never failed, until another thorn crossed my path.

Specialized marks their tubes in larger ranges like 700x 18-28 and 28-38.

lopek77

1st bike - 700 miles on undersized tube, then crap on Chicago's South side on my way to Michigan forced me to change it. Other than that, undersized tubes lasted even up to 3000 miles, then luck runs out, and I find that lost, rusted nail...
2 nd bike - I changed the tires, and put undersized tubes few months after I bought it...I bought that bike in 2010. Same undersized tubes in it. This bike is out and riding 4 seasons. 13F all the way to 90+.
My wife's bike with 700x45 tires, got my 700x18-23 tube, which got flat just 30 mins earlier. Patched it, put it in, and she is still riding on it for the last 2 summers.
When it comes to flats - it's pure luck, or just lack of it.

milkbaby

No, it doesn't. The tube is held in shape by the tire itself. A 700x25 tire is barely bigger than a 700x23 tire. So the tube is not being asked to stretch much or becoming much thinner and weaker. The tube is already labeled 700x18-23, so how can a tube for a 700x18 be any good being "stretched out" to fit a 700x23? The fact is that it's perfectly fine to be stretched out within a certain range of tire sizes, and anything that is functional for a 700x23 tire will most certainly be okay for a 700x25 tire.

If you treat the inside of the tire as a simple cylinder, then the surface area increase from a 700x23 to 700x25 is only about 1%, so it's not being asked to stretch out much at all.

As mentioned, most flats are a matter of bad luck. Whatever is puncturing your tube is going to puncture it whether it's 1% thinner or not.

LesterOfPuppets

I run 18-23's in 30mm CX tires. Perfect tube for those tires, IMO.

bellweatherman

A similar flat scenario happened to me last summer on a short ride with my wife. Me, on my road bike with 700x23 tires and she on her hybrid/commuter bike with her 700x45 tires. I usually carry 2 tubes and a patch kit,and she usually carries nothing at all since she doesn't stray that far from the house. She got a flat midway through the ride and I was too lazy and impatient to patch her tube on the road, so I said to her that we should just give it a try and use the skinny spare tube I had for her flat just to see if we could make it back. To my surprise it worked! And about 6 months later she actually hasn't had a flat on that tube yet!

So, I've used a 700x18-23mm tube in a 700x45mm tire. It wasn't supposed to work or last as long as it has, but it did. And I don't notice having to pump more air into her other 700x45 tire that has the fat tube in it vs the other 700x45mm tire with the skinny tube in it. So maybe it makes no difference at all what size tube you use so long as it is the right diameter (700c, 650b, 26", etc)?

Narhay

It's fine.

bellweatherman

Some people say it's not good to use smallish tubes in big tires. And some say that it's ok. Anyone changed their mind after reading a few experiences from other riders?

Dfrost 

Nope.