Advice needed: Tyre pressure loss but no puncture found

The tyre showed around 25psi when the tyre pressure low message showed up, I had set it to 34 psi before starting my trip.

BHPian GoCool recently shared this with other enthusiasts.

I had done a 1000 km 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:

• 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?)

• 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!

Here's what BHPian Jeroen had to say on the matter:

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

Here's what BHPian dhanushs had to say on the matter:

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?

Here's what BHPian wildsdi5530 had to say on the matter:

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.

Here's what BHPian ShivWason17 had to say on the matter:

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.

Here's what BHPian krishnakumar had to say on the matter:

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.

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