Inconsistent PSI Run Flats
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Intermediate
Joined: Oct 2024
Posts: 28
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Inconsistent PSI Run Flats
I have been noticing that I am putting air in my front driver tire often. It appears to be after I take a cruise and they are warmed up. Of course, this is also the time of year where PSI is inconsistent due to cooler weather. I am in Vegas so over the last 30 days have been going from highs in the 70s to lows in the 40s. Car is in garage. I've taken to my tire shop and they have confirmed no leaks and suggest I may be over reacting due to the weather changes. I am basically filling to 35 PSI cold and withing a few days and a couple hundred miles, the PSI is 27 and tripping the warning. I am also seeing this in my rear passenger also, but not so consistent. Is this a run flat issue that I am not taking into consideration? Front Right and Driver Rear seem to be consistently fine. I just got the car a month ago, tires are brand new. Thanks in advance.
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Which model do you have? Stingray, Grand Spor, Z06 or ZR1? The widebody wheels are notorious for cracking and then lose air.
Last edited by Vetteman Jack; Nov 5, 2024 at 08:35 PM.
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If you check the pressures with a good handheld gauge and then immediately compare with the tire pressure readouts on the DIC, you'll know about any differences between the DIC pressures and actual pressures. Then you can spot pressure loss more easily, though the DIC pressures can easily be off by a pound or two as the tires are warming up.
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JMO, but pressure changes like you are experiencing seem to be way out of norm. I can see a few pounds difference when temps drop a lot, but 8 pounds loss within a couple of days is high.
Melting Slicks
Joined: Oct 2004
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From: Sunnyvale CA
Tire pressure shouldn't be changing that much due to minor temperature changes. Sounds like a cracked rim (unusual for non-GS or Z06) or a leaking tire. How old are the tires?
I had a tire on my C5 that would lose pressure when sitting overnight but would not show bubbles in a water bath. Turned out to be some extraneous rubber that wasn't properly trimmed off the tire preventing it from sealing properly in the wheel. It would only leak when parked in the 'right' position.
I had a tire on my C5 that would lose pressure when sitting overnight but would not show bubbles in a water bath. Turned out to be some extraneous rubber that wasn't properly trimmed off the tire preventing it from sealing properly in the wheel. It would only leak when parked in the 'right' position.
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From: Bonneville Salt Flats
Forget the OEM tire-sensors and get a good gauge. I prefer Meiser and have used them for years. Monitor your tires cold each morning or whenever you leave to drive the car. Fill as the door-decal says, likely 30 psi. Drive as usual and check when you get done driving. They should be somewhat higher due to heating during the day (if air temps increase) and from driving. Do this for a while noting the pressures each morning after the previous day's drive. If you find you still have to add air every few days to meet the 30 psi morning starting pressure doing like this, you have a leak... pure and simple. It can be a wheel leaking, especially if you have a wide-body model. All the best, in any event. 
Intermediate
Joined: Apr 2018
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From: Dallas Texas
Lots of good ideas already, I'd just echo that if you repeatedly have to add air then it's clearly leaking somewhere. Could be the valve stem, the wheel, maybe the bead. Whatever it is it's not a run-flat problem. If it was me, I'd probably do new valve stems first just because that's cheap and easy. When I was younger and worked in a shop we saw bad valve stems all the time. If that doesn't fix it then I'd start looking at the wheels. Just pull one of the ones leaking and take it to a reputable wheel shop (not a tire shop) and tell them your story and have them take a look. Even if it's the wheel it shouldn't be an expensive fix.
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From: St. Louis Metro East IL
You have a leak somewhere - especially since only the wheel / tire just repaired is losing pressure. Troubleshooting 101 - "I just did this and now this other thing is happening." Go back and review the first thing (tire repair) which may also be the root cause of problem #2.
Search for "wheel repair las vegas" and you will get a bunch of choices. I've use Alloy Wheel Repair in St. Louis with very good results. Call any of the shops, describe your issue, and ask how they can help you.
Ron
Search for "wheel repair las vegas" and you will get a bunch of choices. I've use Alloy Wheel Repair in St. Louis with very good results. Call any of the shops, describe your issue, and ask how they can help you.
Ron
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How old are the sensors? They may be reaching end of life.
Bill
