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Slow puncture on and off the car
Slimy38 - 8/4/13 at 12:03 PM

I think I already know the answer to this, but if a wheel has a slow puncture, will it go down faster when on the car compared to sat in the boot? Logic would suggest the weight of the car would increase the pressure, but if it reads 35 PSI on or off the car then the pressure is the same?

adithorp - 8/4/13 at 12:16 PM

If it's got a nail/screw/etc in it then running on it will wiggle the offending item about and let more air out. If it's a leak on the bead (corrosion between tyre and rim) then the movement of the sidewall will accelerate deflation when fitted.

britishtrident - 8/4/13 at 12:51 PM

The tyre carcass distorts under the weight of the car this will usually cause small punctures to leak faster, generally if a puncture leaks faster when the car is parked then it is more likely to be a puncture than a leaking valve or a leak from the rim/bead or the wheel.


If the pressure is within the normal range then the pressure increase between when a spare wheel is fitted and carries the weight of the car is tiny.

Slimy38 - 8/4/13 at 01:48 PM

It's a bead leak, I got the garage to take a look and they cleaned it up as best they could but it's still there. I just want to work out how bad the leak actually is, if it's 1-2 psi a week then I can put up with it. If it goes down quicker I was going to put some gunk inside it to see if that helps.

It sounds like it's the movement on the car that will accelerate deflation rather than simple pressure, so I may have to run it for a bit rather than just let it stand.

adithorp - 8/4/13 at 02:34 PM

Avoid using puncture gunk if you can. It'llbe temporary at best and make any later fix more difficult/messy.

Best way with a corroded rim (short of full refurb) is to use a cup brush on angle grinder to clean the rim. Then use bead sealer (instead of just tyre soap) when refitting. It's basically a rubber solution/paint you put on the beads and fit the tyres with it still wet.

Slimy38 - 8/4/13 at 04:39 PM

quote:
Originally posted by adithorp
Avoid using puncture gunk if you can. It'llbe temporary at best and make any later fix more difficult/messy.

Best way with a corroded rim (short of full refurb) is to use a cup brush on angle grinder to clean the rim. Then use bead sealer (instead of just tyre soap) when refitting. It's basically a rubber solution/paint you put on the beads and fit the tyres with it still wet.


Problem is finding somewhere that still does that sort of repair. I thought my local Chemix did that, as they'd managed to fix a previous one. They cleaned the rim, but they didn't apply bead sealer.

If I could get the tyre off the rim I could apply the sealer myself, but is that even possible without the relevant machinery?

paulf - 12/4/13 at 02:24 PM

I have a tyre that kept going flat on my rover , the wheel was corroded and the last time i had a puncture repair it cost me £20 to have the tyre repaired and balanced. As it started to leak again from the rim going flat every few days and the tyre was over half worn I decided to use an old tin of tyre repair that had been in the locost for the last 7 years, it worked perfectly and hasent lost any pressure over the last 2 weeks.So if the tyre is not very new and you can afford to bin it if it needs a proper puncture repair I would be tempted to use some instant seal .
Paul

Slimy38 - 12/4/13 at 02:38 PM

quote:
Originally posted by paulf
I have a tyre that kept going flat on my rover , the wheel was corroded and the last time i had a puncture repair it cost me £20 to have the tyre repaired and balanced. As it started to leak again from the rim going flat every few days and the tyre was over half worn I decided to use an old tin of tyre repair that had been in the locost for the last 7 years, it worked perfectly and hasent lost any pressure over the last 2 weeks.So if the tyre is not very new and you can afford to bin it if it needs a proper puncture repair I would be tempted to use some instant seal .
Paul


The tyre is brand new unfortunately, it was the tyre fitter that originally pointed out the problem!!

I bit the bullet in the end, a place just down the road has it for refurb right now for £50 all in. £35 for the wheel, £5 for tyre removal/refit, and then the taxman's share. It'll look cleaner than the other wheels, but at least I can go on holiday without having to pack a footpump!