Tubes for 25mm wide rim/25mm tyre

Discuss light weight issues concerning road bikes & parts.
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gordon
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Joined: Thu Jan 17, 2008 10:38 pm
Location: UK

by gordon

Any opinions on the type of tube best suited to a 25mm rim with a 25mm tyre that measures 27mm.

A standard Conti Race 28 18-25 (102g) might be a bit thin once inflated to fit a 27mm width. The reason I state this is that I have had a number of flats with the wide rim/tyre combo run at 95psi, rider weight 155lb/70kg.

The wider conti tube is 25-37 weight is 140g so a fair weight penaly but might be worth it when racing on UK roads.

by Weenie


bombertodd
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by bombertodd

I've had great luck with Michelin A1 tubes on my wide rims and 25c tires.

ToffieBoi
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by ToffieBoi

That is actually something I wonder also.
I am now riding on 23mm wide rims and 24C tires. 25mm wide measured. My inner tube is 20-25C so there is no problem so far. But I don't know what I should do if I go 25C tire. It will be wider than 25mm so, if I should use 25C inner tubes or wider...

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jekyll man
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by jekyll man

I've been running 25mm 4 seasons on hed c2s which makes the tyre width just shy of 28mm, with bog standard 23mm tubes, no problem.
Inflate a butyl tube and see how far it will go; it's a damn sight bigger than the tyre size increase ;-)

Only way I could see a problem is if you try running super light or latex tube and expect it to cope okay...
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euan
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by euan

The smaller tubes should be fine.

As a side note, I use Michelin 23mm latex tubes for cyclocross running between 18 and 28PSI with no issue. So I wouldn't be too bothered about running them in bigger tyres with wider rims.
"Step forward the climber and all those who worship at the altar of lightness" - R. Millar

gordon
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Location: UK

by gordon

Cheers,

The wider tube is pretty chunky, I just have this image in my head of a fully inflated ballon being pricked with a pin as opposed to a less inflated ballon that is harder to penetrate.

I might try the heavy tube on my training wheels and see how long I go without a flat.

HillRPete
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by HillRPete

Think once something penetrates the tyre, all bets are off. Maybe it helps a tiny little with pinch flats though when the tube is not so stretched?
Been running the Conti 28-32 tube with Vittoria Pavè Open 27mm, but once the tube has been in use and is remounted, it's stretched and almost too much to cram into the tyre. Guess using the smaller one in the first place would have been fine.
Last edited by HillRPete on Sat Feb 01, 2014 7:47 pm, edited 1 time in total.

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DMF
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by DMF

The actual amount of material stretch per square inch, of a 20-25mm tube mounted in a 23mm actual width tire or a 27mm actual width tire, is just miniscule. As said, if you're running ultralight tubes (like 65g for butyl) then you are pushing your luck. But with standard "light" 100g butyl tubes, I bet the tubes themselves aren't the cause.

How did the tubes puncture? Snakebite, around the valve, pricked, ripped, torned, pinched? Where on the tube? Both front and rear? Etc...

What I mean here is, punctures happen for a lot of reasons, the tubes could have been chafed on the edge of the rim tape for instance.

by Weenie


gordon
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Joined: Thu Jan 17, 2008 10:38 pm
Location: UK

by gordon

Generally sidewall impact on sharp stones road debrie. Might have more to do with the sidewalls being more exposed on wide rims. Most punctures were on a 23mm rather than a 25mm tyre.

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