[Jonathan Arpith]

Today I travelled from Salem to Bangalore starting at 5 AM. Planned to stop at Burger King/Saravana Bhavan after Krishnagiri to have breakfast. When I stopped I noticed my rear right wheel was completely flat. Touched it and the temperature was warmer than usual. Since it was an early and hurried start, I didn't check the tire pressure or even a visual check.

Filled air in nearby tire shop and since it held up well, proceeded and reached Bangalore. After reaching I again checked and there is drop of around 3 PSI. So definitely a puncture.

I'm curious to know how long can we drive with flat wheels without any noticeable damage? The tire and wheels (alloy wheels) look fine externally. Though I'm not sure if there's any other damage. I was maintaining max speed around 100 and car handled fine. There was no noticeable drop in FE as well.

So I'm wondering if I got the puncture just before I stopped, or did I drive with a flat tire for quite some distance?

[GTO]

No way you'd be able to drive for too long with a completely flat tyre; you would most definitely have noticed the car behaving weird.

Would suggest getting your tyre completely inspected at a professional shop like Madhus. Last thing you want is a blowout at speed due to sidewall damage.

This happens to all of us in cars without proper TPMS. My 530d has a stupid ABS-based tyre pressure warning system which needs the car to be at speed to work. I get low pressure warnings only above 60 - 80 kmph. The other problem is, the 18" rims get bent easily. So there have been a number of times I was running with low tyre pressure without even realising it. The tyres luckily have been okay (on runflats now).

[HighOnSpeed]

The question you should be asking is whether you can run your tyre at all when it is flat. Not all tubeless tyres are designed to be run-flats, so you risk damaging the sidewall and the rim if you are not careful. As GTO mentioned, it is better to let a professional examine your tyre to determine if there is any unapparent damage in case you drove a substantial distance on a flat. Also, on flat tyres, it is recommended not to drive at speeds over 90kmph, but I would restrict it to much lower speeds(<40kmph) or swap it out with a spare. Imagine hitting a pothole at highway speeds in a fully deflated tyre!

[Asoon]

May be it is a faulty / leaky valve
It is hard to believe that a punctured /flat tyre held itself from Krishnagiri to Bangalore at 100+ speed after fill-up and lost only 3psi. A tyre damage [puncture] (a nail or something) would have amplified in such speed / distance and you would have noticed a flat again after 20-30Kms

[narayans80]

Depends on how quickly the air pressure reduces! A 3 psi reduction is not a flat tyre, you may not have

1. Immediate loss of pressure - Experienced this twice. Your balance will be off straightaway and you'll have to stop immediately. More you drive (even as little as 500 meters) you'll shred your tyres.
2. Slow loss of pressure - I filled 35 psi at an IOC that morning. When I left home about 1 pm I didn't feel anything at low speed. However once I crossed 60 I felt a wobble on the rear right. The TPMS showed 23 psi. Took the car to a nearby tyre shop, who diagnosed that whoever filled air earlier that day had broken the valve and caused a slow puncture. In this case I had drive < 5 km and < 2 km from the time I realized the puncture.
3. Incredible stroke of luck - I wrote about this event here (2023 Edition | Your must-have car accessories today). A nail was embedded enough to not the air out. I had a 4-5 psi loss in pressure, but did not reduce further even when stationary next day. I survived about 400 km with this.

[deep_bang]

Originally Posted by Jonathan Arpith

Filled air in nearby tire shop and since it held up well, proceeded and reached Bangalore. After reaching I again checked and there is drop of around 3 PSI. So definitely a puncture.

When you filled the tire, it would be the cold tire pressure. When you checked again after a long drive, it would be hot tire pressure which would be 3 to 4 psi more. So in your case the total loss is likely to be 6 to 7 psi. Probably a small puncture but if it was really that small it means you must have driven for quite some time for all that air to drain out.

Either way, do post what you actually found - whether there was puncture or whether it could be a valve leak?

[Jonathan Arpith]

Originally Posted by GTO

No way you'd be able to drive for too long with a completely flat tyre; you would most definitely have noticed the car behaving weird.

Would suggest getting your tyre completely inspected at a professional shop like Madhus. Last thing you want is a blowout at speed due to sidewall damage.

So, as advised I took my car to Madhus yesterday. They checked and confirmed that everything is fine. No damage to tyre or wheel.

Originally Posted by deep_bang

When you filled the tire, it would be the cold tire pressure. When you checked again after a long drive, it would be hot tire pressure which would be 3 to 4 psi more. So in your case the total loss is likely to be 6 to 7 psi. Probably a small puncture but if it was really that small it means you must have driven for quite some time for all that air to drain out.

Either way, do post what you actually found - whether there was puncture or whether it could be a valve leak?

You are right. I checked the pressure after 2 hrs and it had dropped to 25 psi, so a drop of 7 psi. It was a small puncture and got that fixed from a local puncture shop.

So does it mean I got the puncture some time before I stopped, the air drained slowly and I stopped just at the right time? Because there was no change in the vehicle behaviour, no vibration or pulling and there is no damage to wheel or tyre.