Tyre Pressures

[MALT]

I have a road bike with skinny tyres and I also have an excellent frame mounted pump. The pump has no gauge though. Is it possible to over inflate the tyres using such a hand pump?

The reason I ask is that I recently suffered a puncture without any intrusion into the tyre, on a tube that was two days old, the rim tape is in excellent condition with no sharp bits poking through. I never use tyre levers to fit a tyre, so it is unlikely that I nipped the tube while fitting it. There is nothing poking through the tyre, and the only damage (a pinhole) is on the inner circumference of the tube.

The tyre was rock hard after using the bike for a couple of miles (to and from the barbers) as I checked it by flicking both tyres and they both gave a "bing" in reply after the ride. Two hours, outside in the sunshine (it was a couple of weeks ago), later and the rear tyre was totally flat.

The incident left me lacking confidence in cycling, although I have ridden the bike to work and back (12miles total) a few times since without any repetition of the problem.

Are there any rules of thumb regarding getting the tyre pressure right without a gauge?

TIA

 

[Citius]

Are there any rules of thumb regarding getting the tyre pressure right without a gauge?

You just put your finger on it - no pun intended.

 

[Cyclist33]

A puncture just such as you described occurred with me on a new pair of wheels a couple of years ago. It turned out the rim joint was slightly off, by a fraction of a millimetre, so that there was a tiny sharp point on the inner rim.

I sanded it off a bit with puncture repair sandpaper. Sorted.

 

[jonny jeez]

I have a road bike with skinny tyres and I also have an excellent frame mounted pump. The pump has no gauge though. Is it possible to over inflate the tyres using such a hand pump?

The reason I ask is that I recently suffered a puncture without any intrusion into the tyre, on a tube that was two days old, the rim tape is in excellent condition with no sharp bits poking through. I never use tyre levers to fit a tyre, so it is unlikely that I nipped the tube while fitting it. There is nothing poking through the tyre, and the only damage (a pinhole) is on the inner circumference of the tube.

The tyre was rock hard after using the bike for a couple of miles (to and from the barbers) as I checked it by flicking both tyres and they both gave a "bing" in reply after the ride. Two hours, outside in the sunshine (it was a couple of weeks ago), later and the rear tyre was totally flat.

The incident left me lacking confidence in cycling, although I have ridden the bike to work and back (12miles total) a few times since without any repetition of the problem.

Are there any rules of thumb regarding getting the tyre pressure right without a gauge?

TIA

New rim tape?

 

[MALT]

But the old rim tape is in excellent order, nothing protruding into the tube. I have done seventy miles since replacing the tube again, but I don't pump the tyres up so hard anymore, fearing that the pressures may exceed their maximum if the sun shines on the tyres again (no danger of that this week!).

 

[Profpointy]

[QUOTE 3822602, member: 9609"]I have only ever had punctures like that when my tyres have not been inflated enough and the tube has been nipped from something on the road. Bike mounted pumps often don't get anyway near the correct pressure - try the following - blow your tyre up as hard as you can, then ask in a LBS if you can borrow a track pump, it will probably have a gauge on and this will show what pressure you really have.

could the heat of the sun pop a tyre ?
Tyre blown up to 100psi at 20°C
heat air up by 50° to 70c so an increase in volume of 17% (from proportional increase in kelvin 343/293)
((100+15)*1.17)-15 = new pressure 120psi (assuming tyre volume does not increase, and it probably would)
so if my understandings are correct with the above (and I am not that confident) then I doubt the sun could ever pop a tyre.

EDIT : @Profpointy am i even remotely close with the above air pressure temperature thing ? I am thinking you may know this stuff[/QUOTE]


EDIT - misread your explanation sorry. Thought you meant heat of pumping so deleted my first attempt



If you meant heat of sun calcs look ok - PVT = constant for a give amount (mass) of gas with T in Kelvin. That said 70C sounds pretty warm

 

[Profpointy]

and to the OP - get a track pump. I didn't have one for years and thought it an indulgence. Biggest single performance improvement in kit

 

[adscrim]

It may just have been a faulty tube. Over inflating is more likely to result in the tyre coming off the rim and not the tube failing. Check the rim tape again - I've seen rim tape that looked fine until the fourth check where a small (tiny) shard of metal was found in the weave of the tape.

 

[byegad]

Track pumps make getting the pressure right a breeze.

 

[MALT]

Thanks chaps. Will get a track pump - saw them for £6 in a supermarket recently.

 

[Citius]

Thanks chaps. Will get a track pump - saw them for £6 in a supermarket recently.

I would avoid a £6 track pump - unless it is something like a Topeak Joeblow sport which had been discounted from £30 (unlikely). Worth spending on a decent one.

 

[adamhearn]

Citius is spot on, an Aldi (or similar) track pump for £6 is not a worthwhile purchase. I would also recommend the Joeblow Sport pump!

 

[andyfraser]

Another Joe Blow Sport user here. Highly recommended.

 

[Profpointy]

I bought a Lezayne - it's a beauty albeit £50 or £60 iirc

 

[bpsmith]

Joe Blow for me too. Regularly on offer closer to £25, but will last for years and really quick to inflate to high pressures. Worth the spend without question. Exactly as @Citius states.