L134 

The question of whether or not one can use a tube of one size with a tire of another size seems to come up frequently. Today, the sidewall on my Schwalbe 700C 50mm Racing Ralph tubular failed. I cut the tire open to salvage the tube. It is embossed "Schwalbe 26" No. 13 ETRTO:40/62-559." So there you have it, 622 tire manufactured with a 559 tube. Seems if you can fit the tube in and pump it up you are good to go.

Andrew R Stewart 

Salvaging sew up tubes... Even when I rode only them I still didn't do that

I will seriously add that many sew ups are made somewhat undersized WRT diameter. I've mounted more than a few "700C" sew ups that initially looked like 26" ones. I have long felt that the tube/tire diameter fit is less the issue as compared to the tire/tube width match. Andy

Bill Kapaun

A 622mm is about 11.3% larger diameter than a 559mm bead.
That's about like stretching a 1.8" dia tube to 2".
We'd think nothing of doing the latter.

L134 

Haha, not sure I've ever used one but I still do it. You never know.

FBinNY 

A tube is simply a balloon and like any other balloon will hold their in any size within a broad range. All the structure comes from the tire which doesn't care what tube is inside as long as it's willing to stretch out all the way against the walls.

FBinNY 

A tube is simply a balloon and like any other balloon will hold air at any size within a broad range. All the structure comes from the tire which doesn't care what tube is inside as long as it's willing to stretch out all the way against the walls.

bikebikebike

Agree except where there is uneven rubber around the valve.
Failure at valve tire interface accounts for about 1in 15 of my tube failures, but that mat not be the mechanism
and s on older tubes as a rule

oldbobcat

Of course, the more you stretch it, the thinner and more porous it becomes. Yes, it works, but is it optimal?

Andrew R Stewart 

Depends on how long you need the tube to hold and what cost should it fail. Sizing down the tube's width was (might still be if tubeless hasn't taken over another type of cycling...) a classic BMX trick to lighten up the rotating mass.

I only ride tubed tires and try to fit the widest tube that won't fold over on itself. Just to minimize the stretching of the wall. One more reason why I'm slow Andy

oldbobcat

There you are.

Haven't BMX racers discovered latex tubes?

tFUnK

Makes me want to take apart old tubular tires to see what are inside.

oldbobcat

Just a tube. If it's a nice tire, a latex tube, and a chafing strip of thin cloth to protect the tube from the stitching and seam.

And the tread is just a strip of rubber compound either cemented or vulcanized to the cloth casing. Sometimes with a kevlar layer sandwiched in between.

Clement made a tire called the Paris-Roubaix. 26 mm of silk casing, latex tube and chafing strip, and a thin layer of closed-cell foam sandwiched beneath the tread. Pure luxury for the pave.

We used to repair them after the ride, over a couple beers. Then I moved to Boulder, where they paid other people to repair them. Nowadays, people just throw them out.