Tires and Tubes Query

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GeorgeS

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Oct 11, 2008, 9:16:52 PM10/11/08
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I have some Michelin tubes designated 700c x 18/23. I assume this
means that the tubes are designed for use with tires in that range.
But on the side of the box there are listings under "Code chambre a'
air" for 700 x 25/32, 700 x 35/40 and 700 x 35/47. What does this
mean? Can the tubes be used in the larger tires with more air?
George

Brian Huntley

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Oct 11, 2008, 10:44:52 PM10/11/08
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Yes, probably, BUT....

They'll be stretched thin and will be more likely to puncture and/or
fail.

So, okay for emergency use, but I'd try to get one more my size.

Peter Jon White

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Oct 12, 2008, 10:27:44 AM10/12/08
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It's just a list of other tubes that Michelin makes. Think of it as a
bit of advertising. It's a very bad idea to use inner tubes designed
for skinny tires in fat tires. Use those tubes in the tire sizes
they're rated for; 18mm to 23mm.

On Oct 11, 9:16 pm, GeorgeS <Chobur...@gmail.com> wrote:

tss...@sonic.net

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Oct 12, 2008, 6:48:02 PM10/12/08
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>
> It's just a list of other tubes that Michelin makes. Think of it as a
> bit of advertising. It's a very bad idea to use inner tubes designed
> for skinny tires in fat tires. Use those tubes in the tire sizes
> they're rated for; 18mm to 23mm.

I agree that it's not a good idea in the long term. But I've found that
carrying one spare which is skinny often makes it easier to change a tube
beside the road, especially in difficult conditions (rain, high heat,
etc.). I seem to be less likely to pinch the tube when it's on the small
side (maybe one size) for the tire.

Of course you're supposed to swap out the skinny tube for one of the right
size when you've stopped for the night. Something I sometimes even
remember to do.

bullcitybiker

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Oct 13, 2008, 7:30:47 AM10/13/08
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Famous wrench Jim Langely recommends using tubes one-size smaller to
make it easier to change a tire. I picked
up his tip a couple of years ago and have had good success: no
increase in flats, and when I do flat, I can change
the tube with no levers. I run 18/23 tubes in my Conti 25s and 28s.

Branson

http://www.jimlangley.net/wrench/flattiretwo.htm

Peter Jon White

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Oct 13, 2008, 10:24:03 AM10/13/08
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You've been a bit lucky. It depends on the tube, and it depends on how
accurately the tube manufacturer labels the tubes for sizing. Where
you run into trouble is at the valve. The valve acts as a stress riser
because the rubber at the valve has to stretch more than other parts
of the tube.

Brian Huntley

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Oct 13, 2008, 12:07:47 PM10/13/08
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On Oct 13, 10:24 am, Peter Jon White <peterjwh...@gmail.com> wrote:
> You've been a bit lucky. It depends on the tube, and it depends on how
> accurately the tube manufacturer labels the tubes for sizing. Where
> you run into trouble is at the valve. The valve acts as a stress riser
> because the rubber at the valve has to stretch more than other parts
> of the tube.

Yes, and of course it's all but impossible to patch near the valve, so
the tube would be useless in such a case.

landotter

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Oct 13, 2008, 4:50:34 PM10/13/08
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Lucky indeed. That's why I do the opposite and "size up" on tubes, as
they run small. The bikes that run 30mm and 32mm tires get "35mm"
tubes which pretty much don't have to stretch any at all to fit the
tire carcass. They aren't bunched up in there either. ;-) Utterly
reliable.

tarik saleh

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Oct 13, 2008, 7:00:58 PM10/13/08
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Wow. Ok. I think this is about the biggest overstatements I have seen. Lucky? Come on.

 I have run road tubes in cross tires for years and years with no problems. They get a little thinner sure, nor is it ideal, but really,  you can blow up an unconstrained road tube to 4" in diameter and it won't pop or tear. The valve is a stress riser, but that is why there is a lot of extra material there.  Michelin tubes are probably some of the nicest tubes around, as well. Still talced and seamless.

Buy the right size when you are getting new tubes, but use what you got and don't worry about it, unless you are running 29erx2.3 tires. Up to 35mm or so, eh, I don't think it is a "very bad idea". 

Later

Tarik
--
Tarik Saleh
tas at tariksaleh dot com
in los alamos, po box 208, 87544
http://tariksaleh.com
all sorts of bikes blog: http://tsaleh.blogspot.com

Peter White

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Oct 13, 2008, 7:18:01 PM10/13/08
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Very good point.

Unfortunately, too many manufacturers label tubes with larger sizes than they actually are. This is done so that the manufacturer can claim to be selling a tube for "X" size tire at a lower weight. Smaller diameter tubes weigh less of course. So if you can take a tube that's the proper size for a 28mm tire and label is as being a 35mm tube, you get to call it a very lightweight 35mm tube.
--
Peter White

Peter White

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Oct 13, 2008, 7:30:36 PM10/13/08
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I have no doubt that you have had the experience you relate. However, you are one individual. And if you ride a lot, you'll probably go through quite a few tubes due to punctures, so you're less likely to be using old tubes.

But even with a new inner tube, if it's stretched inside the tire, and you get a piece of glass that just barely reaches the tube, a stretched tube will cut when a tube that's the right size is far less likely to, since there's no stress in the rubber as it's constrained by the tire. Take that tube with the tiny cut in the surface out of the tire and inflate it, and that tiny pin-prick will open.

On Mon, Oct 13, 2008 at 7:00 PM, tarik saleh <tarik...@gmail.com> wrote:
Wow. Ok. I think this is about the biggest overstatements I have seen. Lucky? Come on.

Let's keep it civil, please.



--
Peter White

brendan stallard

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Oct 13, 2008, 7:46:03 PM10/13/08
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<<<if you ride a lot>>>

I rode a lot, all across Europe, and now most of America, which is a bit
of a different environment.

The most punctures I ever got was through bad wheel building. If the
wheel is built properly, it'll work okay.

After a few years experience, I realised it was down to the wheels and I
NEVER repaired punctures after that, but replaced the tubes. Made
everything right and it was okay.

24 miles a day, back and forth and once I'd adopted the above policy and
told the wheel builder that I'd belt him round the head if there were
any spare bits left lying around...things were good.

Civil, I hope.

brendan

tarik saleh

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Oct 13, 2008, 8:18:27 PM10/13/08
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On Mon, Oct 13, 2008 at 7:00 PM, tarik saleh <tarik...@gmail.com> wrote:
Wow. Ok. I think this is about the biggest overstatements I have seen. Lucky? Come on.

Let's keep it civil, please.
 

Alrighty Peter,

Sorry for incivility. You overstate the problem using over the top language though, hence 'come on". It is a mild issue at best. Its not "lucky" to have success with this, nor is it a "very bad idea".

Tarik



 

bullcitybiker

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Oct 13, 2008, 9:39:29 PM10/13/08
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If I notice an increase in flats, I'll consider what's been posted
here. But I'm very happy with the number of flats I've had since using
this technique, maybe half a dozen in the last 10,000 miles, including
none in a very wet PBP. Instead of luck, I chalk it up to maintaining
my bike well, picking good lines through/around debris, and running
good quality tires. Perhaps I should go buy that Powerball ticket this
weekend though..

Branson

landotter

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Oct 13, 2008, 11:56:04 PM10/13/08
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On Oct 13, 6:00 pm, "tarik saleh" <tariksa...@gmail.com> wrote:
> Wow. Ok. I think this is about the biggest overstatements I have seen.
> Lucky? Come on.
>
>  I have run road tubes in cross tires for years and years with no problems.
> They get a little thinner sure, nor is it ideal

If you're constantly swapping tubes and tires it's not a big deal. If
you have a set of wheels that you need to depend on to tour or even
commute on, it's a huge deal. Using too small of a tube stresses the
valve/tube juncture on presta tubes. I've had a few pullouts over the
years till I learned to "size up"--as I don't race and ride several
bikes that will have the same tires mounted for a year or two with the
subsequent pump abuse as well. On my rugged city bike I run schraeder
valves through Alex DM18 rims that I gladly drilled myself. Schraeder
valves are far superior to presta, but only for wider rim applications
alas.

Peter Jon White

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Oct 14, 2008, 10:33:35 AM10/14/08
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Since you seem to be in a mood to argue, I'll bite. ;-)

Please explain exactly why you state, " nor is it ideal,"

In other words, in your opinion, what is less than ideal about using a
skinny tube in a fat tire?
> in los alamos, po box 208, 87544http://tariksaleh.com

Mike Rodgers

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Oct 14, 2008, 12:35:52 PM10/14/08
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Since everybody else threw there 2 cents in, here are mine.
I use my bike for commuting on less than ideal roads (kaliche rock, chip
seal). I keep them close to maximum psi. If the tubes are designed for
narrower tires, I get frequent failures where the stem is glued to the
tube. It separates. I've never had this problem when the tube is sized
for the tire. I know I put a lot of abuse on the tires and I do not
need tubes that cannot handle it. I buy the size called for. My tires
are 27 x 1 1/4 inch with a maximum psi of 100.)
Mike

tarik saleh

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Oct 14, 2008, 12:43:04 PM10/14/08
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NickBull

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Oct 14, 2008, 1:19:45 PM10/14/08
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One more data point:

I nearly always run the "right size" inner tube for the tire. On my
randonneuring tires (700x30 or 700x32) I get about an average of 1
flat per 5000 miles. On my commute bike (700x23 tires until I finish
wearing out the ones hanging in my basement) I get more like two or
maybe even three flats per 5000 miles, but these are mostly pinch
flats and occasionally splinter flats when I wear the tread too thin.

The one time I violated the rule about "right size" inner tubes was
when I didn't have the right size inner tube for the tire (I had
700x23 inner tube for 700x28 tire). The inner tube lasted a week and
was replaced with another of the same size. That one lasted about a
week, too, at which point I figured out what was the problem and went
out and got the right size innertubes. The inner tubes were stretched
so thin that there was obvious wear in them, even after only a week.
The inner tubes were probably cheapos, and the tires were extremely
stiff Specialized Armadillos.

I'd much prefer to know that I've got the "right size" inner tube in
the tire, even if it takes me a minute or two more to run my fingers
between the tire and rim on each side to double check that the inner
tube isn't pinched.

Nick

tarik saleh

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Oct 14, 2008, 1:36:50 PM10/14/08
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Peter,

Not ideal means that, yeah, the tube is stretched thinner and yes that can cause more flats. This is an argument bordering on the theoretical.If you get a small piece of glass that nicks your tube it is probably going to flat sooner or later anyway.  If you give me the option of going to the store and buying a new tube vs using a road tube in a cross tire, I will put the road tube in the cross tire every time and NOT think about it again. If I get a flat, well darn I will change it. But the question was not WHAT is the best tube to use with my 35mm tires, it was can I use thinner tube in a fatter tire. The answer is Yeah, no problem, use it. This happens all the time.

 You go to a shop, they don't have the right tube in stock, what do you do? Ride around looking for another shop? Mail order the right tubes? What do you do in the meantime. You use the tube that gets the job done. What do you think people did before 29'er tubes were readily available? They ran cross tubes "rated" for 35mm in 50mm plus tires. Hell you can run 29'er tires on open pro road rims and road tubes. If you have the choice, get wide rims and wide tires, if you want to try it out with what you got, do it.

This is not new, this is not a big deal. If you give me the choice to run the right tubes, I will. When you order new tires, go ahead and get the right tubes...  But 10 years ago, it was not that easy to find 35mm presta tubes in a shop.  You could easily get hybrid shrader tubes in fat sizes, and skinny presta tubes.  Everyone ran presta road tubes in there cross tires. And this is not just for racing. I commuted on cross tires for years.

What do you do Peter if someone comes into the shop looking for a 35mm presta tube and all you have are 25mm tubes left in stock?  Do you send them away with no tubes because it is a very bad idea? What if they are tourists coming through at closing time?  I am not telling you to sell people the wrong size tube.

The argument that because I race, I don't experience this, or that since I race I am not an every day rider that needs reliable wheels is just plain old ignorant.  What is the mental picture here?  That I ride on the trainer all year, except for the weekly hammerhead ride where I cleverly put new tires and tubes in each time to avoid flats?    I don't have a follow car when I train, ride or commute and I commute every day. I don't have a mechanic who is giving me fresh tubes for every rides. I maintain my own bikes, I have worked in shops, I have worked for manufacturers and done race support,  I ride some of my bikes into the ground, and I ride some of them ocassionally with long pauses between. I have a fair number of bikes and ride them alot and very differently.

 If you have consistent problems pulling the valve out of the tube, work really hard on your pumping technique. Thats operator error or shitty quality innertubes. If you are buying tubes for 1.50 a tube from bikes direct or some other mail order house, maybe you need to spend a few more dollars on innertubes  Worry about tube matching if you are about to leave for a long tour or you get new tires or you have the option sitting there in front of you.  If you are in a pinch, run what you got. Not a bad idea. Not lucky to get away with it.

I don't even know where to begin with Landotters argument that you should run 35mm rated tubes in 32mm tires. All I know is that I am very impressed you have a LBS that can afford to stock tubes in 3mm increments.

 Do whatever you wish, if you have good flat juju, keep on doing what you are doing, that is a hard thing to maintain. I am not telling you NOT to run the correct sized tubes. In fact I love the right sized tubes. And I like nice tubes...   But please don't tell people that it is a "very bad idea" to run undersized tubes. That is hyperbole that serves no purpose.

Tarik


On Tue, Oct 14, 2008 at 8:33 AM, Peter Jon White <peter...@gmail.com> wrote:
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