Newbie run-flat question on tire pressure

[GunKata]

Hey guys, I joined this site sometime ago, but just recently got an 05 Z51. I've been through several different cars : '01 911 Carrera 4, '06 Evo MR, 04 STi, and a '95 Corvette, to name just a few. However, this is my first car with run flats. I just got it Thursday and noticed that twice now, my tire pressures in the rears (moreso on the LR) are declining rapidly it seems. Currently, the DIC reads 25 LR, and 30 RR (which I believe is spec). Is there something I am missing about run flats - about filling them, or how they react to heat changes, etc? that would cause a significant drop in pressure? I will try to refill the LR again and make sure I tighten the valve cap real good. Any ideas? perhaps I have a puncture/slow leak? I've done some searching, but only saw mention of the valve stems being loose. The car seems to drive and handle fine, and just looking at the tires - they seem alright. Thanks!

[BEZ06]

Originally Posted by GunKata

.......I just got it Thursday and noticed that twice now, my tire pressures in the rears (moreso on the LR) are declining rapidly it seems. Currently, the DIC reads 25 LR, and 30 RR (which I believe is spec). Is there something I am missing about run flats - ......
.....The car seems to drive and handle fine, and just looking at the tires - they seem alright.

Thanks!

First of all, you can't tell a completely flat run flat by looking at it. The stiff sidewall just doesn't flex enough to give you any visual clue. For that matter, you can't even tell if you're getting a slow leak while driving down the interstate at highway speeds - again, the sidewall just doesn't flex enough to give you any clue while you're going straight. That's why you've got to run a sensor in a run flat tire - so you know if you've lost pressure while cruising down the highway, so you can slow down before taking the off ramp at high speed and losing it into the guard rail when you get some sideload on the flat tire.

Second, you've got a somewhat common problem. There are several threads like the one below. Click on this thread to see some advice:

http://forums.corvetteforum.com/show....php?t=1734592

Basically, you may need to just tighten the nuts that hold the sensor in the hole in the wheel. Be careful - the torque spec is only 62 inch-lbs. (that's only about 5 foot-lbs. - not very much torque).

Good luck,

Bob

[GunKata]

Thanks, Bob. I did see that one... I'll go lightly tighten the the nuts that hold the valve stems.