27 x 1-1/8 tubes OK for 27 x 1-1/4 tires?

Can I use tubes labeled 27 x 1-1/8" in tires labeled 27 x 1-1/4"?

Any disadvantage?

Thanks! Please reply to the list.

Yeah, tubes are stretchy so they'll work with tires a bit bigger or
smaller than what they're meant for. For example, I used 700C inner
tubes on 27" wheels, without any problems.

I'd be a little more careful when it comes to width, because if you use
a tube meant for a narrow tire with a wide tire, that means the
material in the tube will be stretched out thinner. That can lead to
slow leaks and make your tubes more puncture prone.

All that being said, I'm using "26 mm max" tubes with "28 mm tires",
and it works fine... The difference between 1-1/8" and 1-1/4" is about
3 mm.

Dan

OughtFour wrote:

Can I use tubes labeled 27 x 1-1/8" in tires labeled 27 x 1-1/4"? Any disadvantage?

They will work, but the disadvantage is that since they are stretched
more, air will be "breathe" through them more easily, requiring more
frequent topping off. There's also a slightly greater risk of puncture.

Art Harris

On 8 Jul 2005 12:09:16 -0700, "Art Harris"
wrote:

OughtFour wrote:

Can I use tubes labeled 27 x 1-1/8" in tires labeled 27 x 1-1/4"? Any disadvantage?

They will work, but the disadvantage is that since they are stretched
more, air will be "breathe" through them more easily, requiring more
frequent topping off. There's also a slightly greater risk of puncture.

Art Harris

Dear Art,

The increase in air loss and puncture risk would be slight
indeed.

Assuming that the tubes were indeed designed for different
sizes (and were not merely the same sizes with different
labels), the tube would stretch 11.1% in one dimension and
thin that much. (For idealized round sections, the figures
are 3.5343" circumference, versus 3.9270".)

So the already small air loss rate might increase 11%. If
the rider topped the tires up every 10 days, he might have
to start topping them up every 9 days.

As for punctures, only near punctures involving debris that
penetrated 89% to 99.9% of the tube wall would become
successful due to the slightly thinner tube wall.

But the number of near-punctures that penetrate more than
90% of the normal tube are vanishingly small. To understand
the typical range of pointy objects, consider the thick
outer wall of a typical "thorn resistant" tube--it's 0.115"
thick, almost 4 times the thickness of an ordinary 0.030"
tube.

Imagine trying to stick a needle 9/10ths of the way through
a tube only 0.030" thick--the margin of error would be only
three thousandths of an inch, about a sheet of paper or so.

Carl Fogel

On Fri, 08 Jul 2005 18:44:05 GMT, "OughtFour"
wrote:

Can I use tubes labeled 27 x 1-1/8" in tires labeled 27 x 1-1/4"?

Yes.

Any disadvantage?

No.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

wrote:
As for punctures, only near punctures involving debris that
penetrated 89% to 99.9% of the tube wall would become
successful due to the slightly thinner tube wall.

It's not just normal punctures that you have to worry about. I've had
more problems with holes and splits* eventually developing in thin and
narrow tubes than thicker and wider ones (in the same tyres).

* Not caused by external objects penetrating, but by roughness/cuts inside
tyre or rim tape.

~PB

On Sat, 9 Jul 2005 02:31:56 +0100, "Pete Biggs"
wrote:

wrote:
As for punctures, only near punctures involving debris that
penetrated 89% to 99.9% of the tube wall would become
successful due to the slightly thinner tube wall.

It's not just normal punctures that you have to worry about. I've had
more problems with holes and splits* eventually developing in thin and
narrow tubes than thicker and wider ones (in the same tyres).

* Not caused by external objects penetrating, but by roughness/cuts inside
tyre or rim tape.

~PB

Dear Peter,

While I can't say that I've had such internal problems on my
touring bike, it seems odd that a theoretical 11% stretching
in one dimension of a 1&-1/8th inch inner tube to 1&1/4 inch
would have much effect on internal problems.

That is, if a rider somehow wears a hole in the stretched
inner tube in 100 weeks of riding, then it seems likely that
an unstretched tube would have lasted only 10-12 more weeks
more.

I'm not sure how long "eventually" is for unpunctured tires
to develop holes and splits, so the 100-week example may be
wildly off.

Carl Fogel

wrote:
On Sat, 9 Jul 2005 02:31:56 +0100, "Pete Biggs"
wrote:

wrote:
As for punctures, only near punctures involving debris that
penetrated 89% to 99.9% of the tube wall would become
successful due to the slightly thinner tube wall.

It's not just normal punctures that you have to worry about. I've
had more problems with holes and splits* eventually developing in
thin and narrow tubes than thicker and wider ones (in the same
tyres).

* Not caused by external objects penetrating, but by roughness/cuts
inside tyre or rim tape.

~PB

Dear Peter,

While I can't say that I've had such internal problems on my
touring bike, it seems odd that a theoretical 11% stretching
in one dimension of a 1&-1/8th inch inner tube to 1&1/4 inch
would have much effect on internal problems.

That is, if a rider somehow wears a hole in the stretched
inner tube in 100 weeks of riding, then it seems likely that
an unstretched tube would have lasted only 10-12 more weeks
more.

I'm not sure how long "eventually" is for unpunctured tires
to develop holes and splits, so the 100-week example may be
wildly off.

I've had tubes fail like this after 150 weeks, and fewer weeks, right down
to 5*. (I should stress that this is a /general/ observation with
relatively thin tubes, not specifically with 1 1/8 tubes in 1 1/4" tyres).

So, because the tube only stretches by a further 11%, all potential
problems are only 11% worse**, whatever type of problem? Neat theory but
it it really as simple as that? It doesn't seem like that when ultralight
tubes half of normal weight (so half as thick) have been far more than
twice as unreliable, in my experience.

An 11% improvement is worth considering anyway. Personally, if there was
a choice, I would only opt for a narrower tube to save weight. That's not
a great reason, is it?

* Continental Supersonic 700x23 butyl, which weighs a superstupid 50
grams.

** Reminds me of a Fortean Times headline about the world being "7%
weirder this year".

~PB

A week ago, I would be all for using the skinnier tubes. Then I got my new
wheels and was putting on a set of 28mm tires, and tried using 23mm tubes,
'cause that's what I had lying around. The first one blew out at 95psi. I
thought i'd pinched it when seating the bead and tried again. I put on
another one, and it only made it up to 80psi. I then noticed just how tiny
the tube was compared to the tire. I went and bought some 32mm hybrid tubes
and had no problems, other than a now wildly out-of-true wheel that hadn't
even been between my droputs yet.

Ah, well. I could use the truing practice.

Honestly, I'm surprised my neighbors didn't call the cops. They probably
thought I had a meth lab that blew up. Twice.

-HW

Hank Wirtz writes:

A week ago, I would be all for using the skinnier tubes. Then I got
my new wheels and was putting on a set of 28mm tires, and tried
using 23mm tubes, 'cause that's what I had lying around. The first
one blew out at 95psi. I thought I'd pinched it when seating the
bead and tried again. I put on another one, and it only made it up
to 80psi. I then noticed just how tiny the tube was compared to the
tire. I went and bought some 32mm hybrid tubes and had no problems,
other than a now wildly out-of-true wheel that hadn't even been
between my dropouts yet.

You have some other problem, small cross section tubes do not cause
blowouts, especially ones that make noise. Your tire came off the rim
and would do so with any size tube that you mounted the way you did.

Ah, well. I could use the truing practice.

Don't look there fore an excuse, the tire was not on the rim.

Honestly, I'm surprised my neighbors didn't call the cops. They
probably thought I had a meth lab that blew up. Twice.

You'd better have another look at how you mounted the tire and
consider an FAQ item that addresses that subject:

http://www.sheldonbrown.com/brandt/blowouts.html

Jobst Brandt