Tyre pressures and rider weight

[lulubel]

I wouldn't have thought that running a tire slightly soft would increase the risk of punctures from sharp objects poking through the tire. If anything I would have thought that this would be reduced as the tire will put less pressure on the sharp object and conform over it to a greater extent when the tire is slightly soft, although this is only my own theory, so could be incorrect.

Of course, there's the opposing theory that a harder tyre will "ping" sharp objects out to the side, while a softer one will roll over them and give them a chance to catch in the outer casing, ready to work their way through the tyre and pierce the tube a few miles down the road. Also, just a theory, and just as likely to be incorrect.

 

[black'n'yellow]

Of course, there's the opposing theory that a harder tyre will "ping" sharp objects out to the side, while a softer one will roll over them and give them a chance to catch in the outer casing, ready to work their way through the tyre and pierce the tube a few miles down the road. Also, just a theory, and just as likely to be incorrect.

take two balloons - fully inflate one, semi inflate the other. Then stick a pin in both. Which one is easier to burst..?

 

[Sittingduck]

Lol

How do you define a 'fully' inflated balloon?
If it goes 'pop'... then you over-cooked it!

 

[black'n'yellow]

Lol

How do you define a 'fully' inflated balloon?
If it goes 'pop'... then you over-cooked it!

to be fair, it's just an anecdote - not a peer-reviewed study....

 

[lulubel]

take two balloons - fully inflate one, semi inflate the other. Then stick a pin in both. Which one is easier to burst..?

I can understand how that works with balloons, but I don't think the analogy is a very good one, to be honest. Deliberately sticking a pin squarely into a balloon is very different to accidentally coming into contact with a piece of sharp road debris that probably doesn't contact the tyre perfectly centrally or square on.

The difference, as I see it, is that a softer tyre compresses more where it contacts the road, therefore creating a wider rolling surface. Unless the sharp item is perfectly centred under the tyre, the more the tyre is compressed, the more likely it is to roll right over it and pick it up. The curved surface of a hard tyre, on the other hand, may just brush it, and might even push it away.

I agree that a sharp object that's perfectly centred under the tyre is more likely to pierce a hard tyre than a soft one. However, that isn't what happened to me the other day. The piece of glass that caused my puncture wasn't perfectly centred and didn't pierce the tyre instantly on contact. It was picked up when the grippy outer layer of the tyre rolled over it, and took some time to work its way in.

 

[Eribiste]

I pump 'em up to 110 psi, (700 x 23 that is) now I've got a proper pump with gauge and all. Then I anoint them with hope.

One of these days I'll rush out and get a couple of tubes and a set of levers just in case the p devil comes a callin'.