[S_U_N]

On our Cedia, the right rear wheel lost pressure a month ago. I could see it visually that that the Bridgestone tubeless tyre was almost flat. I measured the pressure using my Michelin digital meter and it was down to 10 psi. So, I pumped it up to 30 with my trusty Coido compressor and was off to my trusty puncture wala.

The typical process started with jacking up the car and removing the wheel.
The tyre was filled up with more air and then dipped in his tub of water. No success.
So, after doing some more clean up/ wash with water, he tried soapy water. Still no success.
His best guess was that the valve is cracked, but there is no leakage from it.

So, we set the pressure to 30-32 psi and I was back home after paying him Rs. 40.
I had asked him for the price of valve and he said it is Rs. 150.

Now, I kept observing the air pressure for the last month. The car is not driven much, but did have two trips - 100 km and 250 km on some really bad roads.
Last night, we suspected that air pressure is low. This morning, I checked. It was 22 psi.

Now, I would like to change the valve. TR414 is the correct valve http://www.kwikpatch.com/tubeless-tyre-valves.html

Where can I buy this?

[Aroy]

You can get the valve from any big shop that sells tyres. If you go to a company owned shop of your tyre manufacturer, you may even get it free of cost.

[sagarpadaki]

Originally Posted by S_U_N

On our Cedia, the right rear wheel lost pressure a month ago. I could see it visually that that the Bridgestone tubeless tyre was almost flat. I measured the pressure using my Michelin digital meter and it was down to 10 psi. So, I pumped it up to 30 with my trusty Coido compressor and was off to my trusty puncture wala.

The typical process started with jacking up the car and removing the wheel.
The tyre was filled up with more air and then dipped in his tub of water. No success.
So, after doing some more clean up/ wash with water, he tried soapy water. Still no success.
His best guess was that the valve is cracked, but there is no leakage from it.

So, we set the pressure to 30-32 psi and I was back home after paying him Rs. 40.
I had asked him for the price of valve and he said it is Rs. 150.

Now, I kept observing the air pressure for the last month. The car is not driven much, but did have two trips - 100 km and 250 km on some really bad roads.
Last night, we suspected that air pressure is low. This morning, I checked. It was 22 psi.

Now, I would like to change the valve. TR414 is the correct valve http://www.kwikpatch.com/tubeless-tyre-valves.html

Where can I buy this?

Goto any good Tyre shop. They will replace the value for you. Don't buy from puncher Wallah. They stock mediocre quality and quote high price.

[joybhowmik]

Originally Posted by S_U_N

I had asked him for the price of valve and he said it is Rs. 150.
Where can I buy this?

You will get this valve at any good tyre shop - and the cost is Rs 100 usually inclusive fitment.

[S_U_N]

Got the Triton TR414 valve from the mechanic at Darshan tyres. He did not want his boss to know, so it was a hush hush transaction. Rs. 50 per piece. I took two.

[S_U_N]

Got the valve replaced (the earlier one was a bit swollen).
Now, this morning, there was still some loss in the pressure (about 2.5 PSI).

So, there is something still wrong.

[Latheesh]

Looks like needle puncture, may be on thread wall. I faced this issue few months back and normal pucture repair strips did not work.
Finally had to repair puncture from inside.

[S_U_N]

Originally Posted by Latheesh

Looks like needle puncture, may be on thread wall. I faced this issue few months back and normal pucture repair strips did not work.
Finally had to repair puncture from inside.

Well, the puncture guy has not been able to find any punctures. So far he has tried twice. On both times he used soapy water and normal water, both.
After the second attempt yesterday, I insisted on changing the valve.

After that, there is still some loss of pressure.

[Pseudosage]

Picking up this thread again. Did you figure out what the problem is? Am having a persistent issue with the front left deflating at a faster rate than the other tyres. Please let me know if other threads are more up-to-date on the topic!

[Aroy]

Originally Posted by Pseudosage

Picking up this thread again. Did you figure out what the problem is? Am having a persistent issue with the front left deflating at a faster rate than the other tyres. Please let me know if other threads are more up-to-date on the topic!

My son's City had the same problem. It was ultimately diagnosed to a small puncture. The repairman took the tyre out, washed it clean and then checked it by immersing it in water tank. No bubbles even after 10 minute. So he filled in air to around 50 PSI, and then the bubbles started. The reason according to him is that micro punctures normally do not leak due to static pressure, but when the car is in motion, high pressure and flexing when the punctured portion is in contact with road, opens up the leak.

Another reason is leak from the beads, especially if the rim is deformed or in case of alloys has a minor crack. If both the cases submerge the tyre fully when checking and if no leaks are detected, fill in air at 50 PSI, the leak will show up.

[anandharamanp]

I filled 34 psi of pressure of Nitrogen gas in my Vento Good year stock tyres (from BP petrol Bunk - GST Meenambakkam) and drove around 680 kms on the highway in a span of 6 days(car was ideal for inbetween 4 days). When i went to refill diesel on 7th day, i was shocked to see that tyre pressure had drastically decreased to 29 psi evenly in all tyres. generally my Vento satisfies me with a FE of around 22 KMPL average on Highways when i maintain a speed of 120 KM/hr but i got a FE of around 20 only this time. generally i used to witness a decrease of 1-2 psi every 15-20 days but this time it is really high and shocking.

Following are the questions that comes to my mind.

1) is it normal? I thought nitrogen escapes from tyre at a very low rate and expected the pressure to be decreased by 1-2 psi and not 5 psi.
2) is there any possibility of errors in nitrogen gas inflators?

Please suggest what should i do. I am confused.

Note: i only go for refill and pressure check by around 9 pm and the fuel station is just 4 kms from my home. So i donot think there will be any effect of heating.

[dhanushs]

Originally Posted by anandharamanp

...

1) is it normal? I thought nitrogen escapes from tyre at a very low rate and expected the pressure to be decreased by 1-2 psi and not 5 psi.

Nitrogen and air are pretty much the same for passenger cars. After all air is 80% nitrogen. All the benefits of nitrogen are just hyped too much to market a paid way of pumping air to the tyres.

2) is there any possibility of errors in nitrogen gas inflators?

The possible error in your case, since all four tyres show the same level of decrease in pressure is either a faulty guage, or you had filled up when the tyre was warm/hot, and when it cooled showing a lower pressure.

[anandharamanp]

Originally Posted by dhanushs

The possible error in your case, since all four tyres show the same level of decrease in pressure is either a faulty guage, or you had filled up when the tyre was warm/hot, and when it cooled showing a lower pressure.

Thanks for your inputs, i assume it may be a faulty guage/inflator, as i only go for a refill of fuel or air pressure only by night time. Also i ensure to provide enough interval for the warm tyres to get cooled off before going for top up. Let me check with a different tyre inflator and see the results.

[anandharamanp]

While i was researching over internet the reasons for fast tyre deflation i found the below reasons in the URL:http://www.tirereview.com/why-do-tires-lose-air/ and though of sharing with you all. I am sure team BHp members would have more details but still thought this may be useful.

1. Osmosis of air through the tire casing can lead to a loss of 1 to 3 PSI per month, depending on the specific tire make and model. The type of compounds used in the manufacture of the tire can have a big impact on osmosis. The composition and gauge of the tire innerliner compound also plays a significant role in osmosis.

2. Slow leaking punctures in the tread are the leading cause of tires losing air. A nail embedded in a tire’s groove may cause a loss of 2 or 3 PSI per day, not 2 or 3 PSI per month as with osmosis. You can check the tire pressure before the vehicle leaves the yard in the morning, yet pick up a nail just a few minutes later.

3. Leaking valve stems and cores are another cause of low tire pressure. Over-tightening valve cores can lead to loss of air. There actually is a specification of 4 inches per pound of torque on a tire valve core. Valve core pre-set torque wrenches are available through tire supply companies.

4. Finally, tires lose air through impact breaks. Running over large objects and hitting the curbs on those right-handed turns can lead to air loss, which is usually sudden and will lead to an emergency roadside service call.

[Aroy]

In case of the rim getting bent slightly due to impact (or some defect), the air can leak through the bead seating.

The air can also leak through the lining of tubeless tyres. Normally the lining is quite impervious to leaks, but it does leak at times.

My car runs very little, about 2500 km/year. The air leaks in my case are so little that when I check once a year, the pressure has dropped from 30 PSI to 25.