[GoCool]

I had done a 1000km trip recently. I did nitrogen top up at MRF tyre shop a day before the trip. After 2 days at mid of my trip around 500km, one of the front driver side tyre showed low pressure. I could not find any punctures visually. I took it to another MRF tyre shop in the place I was visiting. We checked thoroughly for puncture with soap water and did not find anything. He checked at the valve and rims as well. Finally he topped up for 40psi and asked me to monitor. I have driven back 500km without any low air pressure issue. I am monitoring it for past two days and I am not getting any low air pressure alert yet. I have below questions:
1) What could be the potential reason for this issue? (The initial top up was improper? I had parked for 4hrs in uneven surface putting more weight in the tyre of discussion? Micro leak? Any thing else that I couldn’t think of?)
2) what should I do next?

Additional information: The tyre showed around 25psi when the tyre pressure low message showed up, I had set it to 34 psi before starting my trip. It was measured with analog external meter. The vehicle is Ford Endeavour and the Tyre make is 2019 Bridgestone Dueler HT and driven less that 20K km. The exact tyre pressure reading will not be shown in the display, it will only show alert when the tyre pressure goes low!

[Jeroen]

There could be several reasons that could cause this. Sometimes punctures are so small they are very difficult to detect, even with soapy water. When the tire is on the car and moving about, those very tiny punctures let out air.

Another reason is you got a reading from a faulty manometer.

There is not much you can do, but keep monitoring it regularly. If the pressure does come down to quickly you need to do another leak test. It might help to take the tire of the rimland inspect also the inside. Another test is to push the complete tire/rim under water and leave if for several minutes to see any potential bubbles appear.

In order for most of the tire pressure system to work correctly it helps to reset them every time you top up tire pressure.

Good luck

Jeroen

[balenoed_]

Originally Posted by GoCool

Any thing else that I couldn’t think of?)

It could be also that the first air fill may not be done properly. In other words, the air filling ball head was not taken out properly when the guy detached it after filling the air, causing the valve to be not seated and sealed properly and hence started leaking. And during the second air fill, the valve got seated properly.

[bhphog]

Three probable reasons (apart from a regular puncture):
1. Leak through minor sidewall puncture or tear. This was the culprit in a tyre of my car which lost pressure extremely slowly but consistently. They are so minor that the bubbles when soapy water was sprayed were very minor.
2. Leak due to a torn valve cap.
3. Bent rim.

[dhanushs]

There might have been a minute leak in your valves after your nitrogen top up and it was cleared after the next top up.

It is always a good idea to check if valves arent leaking air after filling air. Remember the road side tyre wallas using spit to check valve leak?

[wildsdi5530]

I would say the commonest reason is vandalism. Did you park the car in someone else's parking space? Or perhaps near a tea stall where guys sit on the kerb next to your tyre and play the fool? Or any road rage before parking?

This sometimes happens in Bengaluru where there is unexplained loss of pressure due to human reasons.

Another possibility is a hard hit like a pothole or kerb hit can cause pressure loss in tubeless tyres.

As long as there is no observable puncture and the underwater leak test is normal even with a high pressure, don't worry about it.

[MT_Hyderabad]

Gently bend the valve and pour soap water.
Sometimes the valves get minor cracks which release air only when the valve is in slightly bent position.

Then it all depends on how the valve is seated at the broken area. It could be a perfect fit or a minor/major leak.

If this is found to be the culprit, it is recommended to replace all the similar aged valves, as they all will have minor cracks building up.

[5haS_0209]

We've had the same issue in our Honda city for about an year and we were not able to find what was causing the air leak. We would experience the drop only on the front right tyre as well. Seems like there was a crack inside the alloy. Soapy water in a bottle won't help to find the leak. It's just a waste of time. My advice is please visit a shop which has a big bucket of water which would fit your whole wheel entirely (the good old method) to find out where air is leaking from. Doing this, you'll definitely be able to find a solution

[jerrindanny]

Originally Posted by balenoed_

It could be also that the first air fill may not be done properly. In other words, the air filling ball head was not taken out properly when the guy detached it after filling the air, causing the valve to be not seated and sealed properly and hence started leaking. And during the second air fill, the valve got seated properly.

This has happened to our vehicle also. We visited a local tyre shop for air filling and the value was not properly sealed for the front left side tyre. I noticed that the tyre is deflating faster when compared to the other sides. On a visit to the alignment shop, the mechanic suggested the above reason and we were able to conclude that value was the issue.

[ShivWason17]

I faced a similar issue some time back, one tyre was acting very troublesome and the pressure was reducing very slowly. Puncture could not be detected even with soapy water. Ultimately, I got the tyre off from the wheel for thorough inspection and found a number of micro punctures, there were very small pins (not the usual nails) stuck in the tyre, atleast in 3-4 places. I was delaying a complete tyre change for my vehicle since some time but immediately changed all tyres after this.

However, in your case an incorrect top up may be the culprit. If the issue is resolved now then all good.

[dust-n-bones]

While it could be a small puncture, but since you've not had this problem again, it could just be weather.
Tyres can sometimes deflate overnight in cold weather. You re-inflate, and that's all there is to it: https://www.consumerreports.org/tire...r-a2422532504/

[Krishna sankar]

Iam having similar problem in my nexon with Bridgestone tyres. Run less than 10000 KMS. Only the rear left tyre looses 1 PSI every day. The reputed tyre shops could not locate the puncture and concluded that it is valve leak and tightened. In soap test, no leak is dedected. But still i am loosing about 1 PSI every day only in that tyre. All other tyres hold the air pressure for more than a month. What could be the problem? Suggestions please.

[Sameergarg]

The second most obvious reason is damaged rim. Do not any abnormal bubbling or vibration at high speeds. It needs through inspection after hyperinflation of tyre and using soap bubble to detect site of leakage.

[sridhar-v]

I struggled with a similar problem on my Grand Vitara's AllTerrain tyre.
Eventually we inflated the tyre to 45-48 psi and found a very microscopic leak on the transition between the tread and sidewall. It was aggravated during driving and hence pressure drop would happen mainly while driving.
Due to the position of the leak we eventually had to plug the same from the inside of the tyre.

[krishnakumar]

Originally Posted by GoCool

1) What could be the potential reason for this issue? (The initial top up was improper? I had parked for 4hrs in uneven surface putting more weight in the tyre of discussion? Micro leak? Any thing else that I couldn’t think of?)
2) what should I do next?

As many others said, the reasons could be many!

I see that you are from Bangalore. Please take it to Madhus in Lalbagh and explain the problem to them. They are the best tyre experts in Bangalore and should be able to root cause if anything was indeed at fault.

But based on what I read, this could be because of faulty equipment pushing the valve pin in slightly and causing a slow leakage. It was probably reset to its location when the tyre shop filled it again. However, you’ll need a thorough inspection to ensure there is nothing faulty with the valve, sidewalls, rims etc. So take it to some expert like Madhus.

As BHPian Sridhar-V mentioned, I also had an identical issue of a microscopic leak on the sidewall that did not show even while immersing it in the water tub. Reason being, without any load on the tyre, the tiny hole would remain shut but when the car is parked (with the hole side sidewall near the road) or while driving, the squish at the bottom due to vehicle load will open up the hole and result in loss of pressure. It was hard to diagnose this and was found at Madhus only.