Hey guys,

Wandered out for my drive to work this morning and the Tire pressure light came on... So I wandered round and checked all the pressures and they all seemed fine except the RF which was at about 27-28 PSI. I figured that was a reasonable pressure and drove to work with the annoying light on the whole time then filled it with my little compressor (didn't do it at home since I didn't want to wake up my neighborhood) back up above 30. I know I hit something metallic yesterday with that wheel because I heard something bounce.

Now all the rest of the tires are 32-34 depending on the wheel (the last time I filled them it was 100+ now its 69 so that explains the drop) and I know the regular tire pressures are 38 all around. My question is... has anyone ever taken the pressure on a run-flat with a punture?

My feeling is that the pressure should be at or close to 0 if there is a hole in the tire since it is only the sidewalls that are holding it up but I have no experience with run-flats.

What a couple of days. My fiancees car died at her office yesterday so I had to make the 2 hour trip from my office to go and rescue her (flat battery thank God) and now this...

 

like any tire with a leak - the tire can loose SOME pressure due to a smaller leak. TPMS has a threshhold difference b4 it says you lost air (since the pressure will vary by temperature this is a necessary thing)

And this is why a run-flat 'technically' can be repaired: in the case of a slow leak and only running on partial pressure the side wall was not compromised. In a standard tire you can SEE the damage when run 'flat'. If there is no visible sidewall damage most times you can repair a standard tire.

Unfortunately most repair shops are very wary of RF repairs because they can's see damage and therefore have no idea if it was driven more than 50 miles flat . . . . or never.... Or in other words if your rf IS at zero psi you probably need a new tire . ..

I've plugged several rf's with DYNAPLUG and run them for thousands & thousands more miles after finding a simple nail in the tread; when the PSI never dropped much more than 10 psi.

 

+1- In my experience a small drop in pressure comes after a puncture, or a few days before a more serious tire failure. Once some damage to the inner sidewall, and twice with sidewall bulges.

If it were me, I'd inspect it very carefully or take it to a tire shop to check out.

 

If you look at the air pressure sticker on the driver's door you will find the correct air pressure for a car regardless of what it says on the tire.
I beleive that you will find that the correct rir pressure is 38 lbs.
If it is 38, 28 is too low as is 32 lbs.

 

Ya, I'm aware that it should be at 38. The last time I remember putting air in them was following an Autocross when it was 100+ degrees and the tires were hot, the light was activated when it was 69 degrees and the tires were cold so a drop in pressure was expected.

After I pumped it up yesterday the pressure stayed in all day and overnight last night so I think I'm good to go. I did inspect the tire pretty carefully and there is no visable sidewall damage and I couldn't find anything in the tread, sidewall or any damage on the tread that looked like it may have struck something.

I'll keep checking the pressure for a couple of days but I think it may have been a false alarm.

Thanks for the help guys