700c tube in 650c tire

I'd heard it here, but had my doubts... that, in a pinch, you could install
a 700c tube into a 650c tire. Well, I forgot to bring along any 650c tubes
on today's ride with my son (and my patch kit was missing) and, sure enough,
he flatted. As they say, when all you have is a hammer, everything looks
like a nail, and today, a 700c tube was going to be a one-size-fits-all.
Somehow I managed to get it in there without having any obvious folds. It
was a 700C SL (superlight) tube, for what it's worth... don't know if that
made it any easier. Had to be careful, and it took a couple minutes, but it
did work.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

One time I flatted an only had a 650c tube and tried to use it with a
700c tire. I couldn't get it to work as it stretched the tube too much
and I couldn't get the tube to stay inside the tire when installing it.

650c's actually have a outer diameter of about 24 inches where as
700c's are over 26 inches depending on the size.

Jon

Mike Jacoubowsky wrote:
I'd heard it here, but had my doubts... that, in a pinch, you could install
a 700c tube into a 650c tire. Well, I forgot to bring along any 650c tubes
on today's ride with my son (and my patch kit was missing) and, sure enough,
he flatted. As they say, when all you have is a hammer, everything looks
like a nail, and today, a 700c tube was going to be a one-size-fits-all.
Somehow I managed to get it in there without having any obvious folds. It
was a 700C SL (superlight) tube, for what it's worth... don't know if that
made it any easier. Had to be careful, and it took a couple minutes, but it
did work.

When my daughter went off to college with her mountain bike (26" tires)
she had never changed a flat tire. So one day I got a call that one
tire was flat and what should she do. I let her know that there was a
spare tube and tire levers in the seat bag and talked her through the
procedure over her cellphone. She did mention that the tube seemed too
big, but I just told her to stuff it into the tire so as not to pinch
it under the bead and eventually she got it in and pumped it back up.
Months later when she was back home I replaced the tire and checked the
tube. Turned out I must have grabbed one for our 27" wheel tandem by
mistake when I stocked her seat bag since it was 700C/27" tube, not a
26" mountain bike tube.

On another occasion I've used a 700C tube in a 12" trailer tire. That
definitely results in some 'obvious folds' but still works ok.

On Mon, 03 Apr 2006 00:07:03 GMT, "Mike Jacoubowsky"
wrote:

I'd heard it here, but had my doubts... that, in a pinch, you could install
a 700c tube into a 650c tire. Well, I forgot to bring along any 650c tubes
on today's ride with my son (and my patch kit was missing) and, sure enough,
he flatted. As they say, when all you have is a hammer, everything looks
like a nail, and today, a 700c tube was going to be a one-size-fits-all.
Somehow I managed to get it in there without having any obvious folds. It
was a 700C SL (superlight) tube, for what it's worth... don't know if that
made it any easier. Had to be careful, and it took a couple minutes, but it
did work.

Here's an emergency repair technique I learned from "Cranked
Magazine" http://crankedmag.com

When you don't have another tube or a patch kit, get a small stick. A
stir stick from the local coffee bar does fine. Find the hole and
place the stick across it perpendicular to the tube. Flip it over so
the tube hangs from the stick and pinch it tight below the stick.
Give the stick a couple turns like a tourniquet so it's now parallel
to the tube. Hold it tight and carefully place it back into the tire.
Inflate slowly making sure that there's no bulges and the tire is
seated on the rim. There will be a noticeable lump when you ride but
it will get you home or to the LBS.

This method takes advantage of the folds you were careful to avoid.
--
zk