[adisan]

The other day, moments after I started driving, a sound similar to a balloon bursting was heard. I continued driving, because I did not feel anything amiss. A few minutes later, a two-wheeler rider alerted me that the rear wheel was losing air pressure. There was enough time to get to a nearby puncture shop. It would have been about 10-15 minutes before it become totally flat. The guy did not find any puncture, and told me that this is known issue with tubeless tyres. I continued the trip and covered more than 425 km after that, including on some very bad roads, without issues.

These are the second set of tyres for the car and were bought about 1.5 years back. None of the tyres have faced punctures, and all the tyres have held air pressure well so far (no issues of gradual minor leak etc).

This reminded me of two earlier occasions when the same thing had happened. I had parked my car in pilgrimage centres, and had assumed that someone who did not want me to park in that spot might have deflated the tyre.

The first incident was 3 years back,with the old set of tyres.
The second incident was 6 months back,with the present set of tyres.
The third incident was with the present set of tyres, and happened when I was driving.

The rear right wheel was involved in all three occasions. I cannot confirm whether it was the same rim or tyre (wrt the two times with the present set of tyres) because the position might have changed after WAB.

What gives? Any pointers to help avoid such an issue in future?

[dicor]

In your case, we can rule out the possibility of tyre defect here.

Get your rim / alloy checked. Do you every remember hitting a pot hole with full force.

I had developed similar problem in my 2006 model Santro. Every time I use to hit a pothole on highspeed, air pressure use to released immediately for front right tyre. I rectified the problem by placing a tube inside tyre in the defected rim.

[adisan]

Originally Posted by dicor

Do you every remember hitting a pot hole with full force.

Yes, but not the same wheel. The front right wheel hit a pothole at about 50-60 kmph once. It lost half the air, but retains the air properly when refilled. It remains as the right front wheel, whereas this issue is seen in the rear right wheel.

This time I was at crawling speed (over a plastic speed hump like the ones seen in malls) when I heard the bursting sound and the tyre went flat.

[adisan]

Had the wheel checked at a puncture repair shop. The guy said that the valve pin was a bit loose and that he did not find any other issues.

I am still unsure, but hoping that the issue will not recur.

[dwarika]

Originally Posted by adisan

Had the wheel checked at a puncture repair shop. The guy said that the valve was a bit loose and that he did not find any other issues.

I am still unsure, but hoping that the issue will not recur.

Glad to know that it is fixed now. I remember having similar issues with a Maruti 800 5 Speed that used to come with tube and tyre which I got upgraded to tubeless but had valve leak issue multiple times. This was caused because the car was older and the valve were not sitting properly on the rim. The issue was fixed after I upgraded the rims to alloys.

[Akshay6988]

Originally Posted by adisan

Had the wheel checked at a puncture repair shop. The guy said that the valve pin was a bit loose and that he did not find any other issues.

I am still unsure, but hoping that the issue will not recur.

As the valve gets older, the rubber seal on it, which sits inside the hole on the wheel gets hardened and brittle. The roadside chaps who fill in air usually don't hold (support?) the back of the valve and just jam it with the air filler nozzle. This damages the valve and even some cracks may appear. Either use high quality valves or replace them every year - doesn't cost much.

Source - I face this issue on both of my scooters, no puncture yet the tyres loose air drastically.

[PapaBravo]

Originally Posted by adisan

Had the wheel checked at a puncture repair shop. The guy said that the valve pin was a bit loose and that he did not find any other issues.

I am still unsure, but hoping that the issue will not recur.

Hopefully it should not. In all probabilities it was a faulty valve. I have faced the same. Some old tyre shops tap the valve once after filling in the air so that the jammed valve pin returns to its original position.

[greenhorn]

I faced this issue - My tyres would go mysteriously flat every now and then - even after replacing the valve - Was traced to a rusty rim. Now replaced and issue is not there any more

[ankitsingh7]

Originally Posted by dicor

In your case, we can rule out the possibility of tyre defect here.

Get your rim / alloy checked. Do you every remember hitting a pot hole with full force.

I had developed similar problem in my 2006 model Santro. Every time I use to hit a pothole on highspeed, air pressure use to released immediately for front right tyre. I rectified the problem by placing a tube inside tyre in the defected rim.

Completely agree with this
this happened to me as well. If it is not the the rim then it must be the valve. sometimes they have a defect, try getting that changed

[10.00-20]

Originally Posted by adisan

The other day, moments after I started driving, a sound similar to a balloon bursting was heard. I continued driving, because I did not feel anything amiss. A few minutes later, a two-wheeler rider alerted me that the rear wheel was losing air pressure. There was enough time to get to a nearby puncture shop. It would have been about 10-15 minutes before it become totally flat. The guy did not find any puncture, and told me that this is known issue with tubeless tyres. I continued the trip and covered more than 425 km after that, including on some very bad roads, without issues.

These are the second set of tyres for the car and were bought about 1.5 years back. None of the tyres have faced punctures, and all the tyres have held air pressure well so far (no issues of gradual minor leak etc).

This reminded me of two earlier occasions when the same thing had happened. I had parked my car in pilgrimage centres, and had assumed that someone who did not want me to park in that spot might have deflated the tyre.

The first incident was 3 years back,with the old set of tyres.
The second incident was 6 months back,with the present set of tyres.
The third incident was with the present set of tyres, and happened when I was driving.

The rear right wheel was involved in all three occasions. I cannot confirm whether it was the same rim or tyre (wrt the two times with the present set of tyres) because the position might have changed after WAB.

What gives? Any pointers to help avoid such an issue in future?

Hi !

It is very unfortunate that you had to go through the same issue. Just want to know if you are using alloys or steel rim? In case, it is steel rim then you need to inspect thoroughly for any minor bend or deformation in the flange/ bead seating area. Secondly, check the bore where the valve base is sitting. Any sharp edge may damage/cut the valve base. Another important contributor could be the valve inner core. If it not tightened properly, slow but continuous air loss may happen. In that matter, always use a valve cap. But most of the time during air refilling, the technician will forget to put the cap back. Hope this helps.

[waypoint]

I ran into exactly same issue of having flat tyre without a puncture in the night of Friday 08 Apr 2022.

One of the observant pedestrian pointed out the flat backside left tyre to me when I was just about to drive off from the premises of one of the restaurants and I immediately drove to top up air at nearby Petrol station on ST Marks Road, Bangalore after thanking that pedestrian. At the station the tyre pressure was found to be 0 PSI.

I was surprised and embarrassed at the same time because I did not feel much about having a flat tyre while driving, may be because the traffic on roads and conditions of roads in Bangalore just do not let one reach decent speeds to notice any differences and moreover, at that particular time, the traffic was substantially more than what usually it had been since the beginning of pandemic. I did not know, how much I would have driven in that flat tyre.

Over the next two days, the tyre pressure did not drop so it started appearing to me that the flat tyre did not happen due to puncture.

Meanwhile, I searched this forum and found this thread about issues in driving in flat tyres (Car ran 20+ kms on a flat tyre :(). All tyres of this car are relatively new and were put into service in March 2021 and all are Continental UltraContact UC6. This flat tyre did not show any concerning signs of damages that were noted in that thread.

I got my tyre and rim checked thoroughly today at the tyre shop to which I had been going for many years and no issues were found in those inspections.

This is how the tyres sidewall looked like while going for inspection today:


The person inspecting the tyre educated me that when air is filled at air filling stations of petrol stations, sometimes the valve on the tyre do not completely retract making slow leaking of air a possibility and suggested to me to always check for any leaking of air from the valves by applying water on their mouth and observe for bubbling. All these valves were relatively new too as they were also changed at the time of changing all tyres in March 2021.

Lesson learnt: carefully check for air leaks while getting air filled from a petrol station or observe tyre pressure the next day after filling the air

For now, I have swapped this tyre with the spare tyre, which is also the same sized allow wheel having the same tyre and valve.

[adisan]

Originally Posted by adisan

Had the wheel checked at a puncture repair shop. The guy said that the valve pin was a bit loose and that he did not find any other issues.

The issue did not recur, but the attendant at the petrol pump said that the valve pin was s;lowly leaking air, and offered to replace it. The wheel had lost more air compared to the other three, since the previous fill.

The wheel has a new valve pin.

[Chetan_Rao]

Originally Posted by waypoint

...

The person inspecting the tyre educated me that when air is filled at air filling stations of petrol stations, sometimes the valve on the tyre do not completely retract making slow leaking of air a possibility...

Originally Posted by adisan

The issue did not recur, but the attendant at the petrol pump said that the valve pin was s;lowly leaking air...

You guys needs a valve pin tightener/remover, dirt cheap and available online or your nearest automotive spares store. Takes some good old spit and a few seconds per tire to ensure the valves aren't leaking whenever you get air topped up, nothing compared to time & effort required to deal with a flat.

Carry a few spare pins for good measure, no reliance on someone else supplying one.