[Rehaan]

Vishnuvijay,

As everyone has said, it could be any of the following :
1. Valve not functioning correctly
2. Leak at base of valve stem (where it meets the wheel)
3. Puncture (tubeless tyres dont burst, they leak - sometimes very slowly)
4. If you have steel wheels, the flange could be corroded/rusted allowing air to leak.

Originally Posted by headers

Boss..i'd doubt a pump attendant diagnosing a valve leak! We are not in your esteemed company you see


How did the pump guy check the valve leak?

It is actually common practice headers. Its a very basic trick they all use. Some do it all the time, some do it when you tell them you think there is a leak.

They spit on their finger, and then wipe the blob of spit to form a membrane over the valve opening. If a bubble is formed, the valve is leaking.

Always keep your valve caps on. This prevents dirt and dust from getting into your vavle and causing it to leak.

cya
R

[rks]

I cannot think of any rational explanation for the tyre losing 19 psi in two days and then losing nothing much on your long trip lasting two days. Possibly some mischief, as people pointed out.

Anyway in addition to the points made, check the condition of the rim. A rusted or bent steel rim can cause leakage. Secondly, if you had a previously fixed puncture, check it for leakage. In my case there was a slow leak due to failure of a previous puncture.

[vishnuvijay]

thank you again guys.

the rim is alloy. it is not rusted and there is no bend. there was no earlier puncture either.

the ioc pump guy used the saliva technique. yuckkk. but it's ok, i wash and wax my alloy wheels every 2 weeks.

i think it must be the valve. like tsk1979 said, the air escaped when the repair man bent the valve to one side. so the rate of air escaping must be varying.

[PatienceWins]

It must be the valve. Keep us posted. All the Best!!

[headers]

Originally Posted by tsk1979

@headers, if the leak is from the top of the valve it is detectable as the pump attendents often put saliva on it after filling in air(I know its sounds gross, but thats how I have seen it being done).
But when the leak is from the bottom stem ... You need an expert.

That is only the pin being loose [the gross method..saliva..] ..the tearing of the valve usually always happens at the bottom !!

[vishnuvijay]

hi guys, by the time i reached home, my dad had already changed the problematic wheel/tyre and put on the stepney/spare wheel and guess what, he had found a big nair on it. so hehehehe, the problem was a typical puncture.

today, i took the car to a nearby tyre dealer/shop and got it fixed. he charged me Rs.70.

the guy over there took the wheel and filled it up with air and removed the nail with out removing the tyre from the rim. he then drilled a hole over the puncture hole with an electric drill and screwed in a piece of rubber tube like material soaked in some gum into this hole. filled it up with air again and immersed the wheel in a water tank to check for any leaks. thats how it was fixed.

thank you guys for your help and providing so much information.

a bit off topic, but read this.
Does the word 'stepney' exist?

Yes, it does. Stepney is actually the name of a street in Llanelli, Wales where the spare wheels for the motorcar were originally made. Since the tyres were made in Stepney, spare wheels began to be called "stepney wheel". Later, it was shortened to "Stepney". These wheels consisted of ready inflated tyres which could temporarily be clamped over a punctured wheel. Nowadays, of course, the word "Stepney" is mostly heard in countries like India, Bangladesh, etc, which were once part of the British Empire. These days, native speakers of English use the word "spare" instead of "Stepney". The word "Stepney" is unheard of in America.

source : The Hindu : Does the word "Stepney" exist?

[vishnuvijay]

hi guys, i just found this link on how to use the 'do it yourself puncture kit'. please check it out. it's got pictorial instructions.

The Tubeless Revolution - Repairing Punctures: A Breeze on Tubeless Tyres

thank you.

[Mission_Safari]

Originally Posted by vishnuvijay

hi guys, by the time i reached home, my dad had already changed the problematic wheel/tyre and put on the stepney/spare wheel and guess what, he had found a big nair on it. so hehehehe, the problem was a typical puncture.

today, i took the car to a nearby tyre dealer/shop and got it fixed. he charged me Rs.70.

the guy over there took the wheel and filled it up with air and removed the nail with out removing the tyre from the rim. he then drilled a hole over the puncture hole with an electric drill and screwed in a piece of rubber tube like material soaked in some gum into this hole. filled it up with air again and immersed the wheel in a water tank to check for any leaks. thats how it was fixed.

thank you guys for your help and providing so much information.

I know you meant nail but couldn't stop laughing.

[iraghava]

So VV, how big was this "Nair"?? As big as Hydrashok??

[hydrashok]

Originally Posted by iraghava

So VV, how big was this "Nair"?? As big as Hydrashok??

The moment I saw the typo, I knew it was only a matter of time before you'd mention this

[headers]

Originally Posted by vishnuvijay

the guy over there took the wheel and filled it up with air and removed the nail with out removing the tyre from the rim. he then drilled a hole over the puncture hole with an electric drill and screwed in a piece of rubber tube like material soaked in some gum into this hole. filled it up with air again and immersed the wheel in a water tank to check for any leaks. thats how it was fixed.

I thought One had the remove the tyre and put the sealant from inside, iron it , then trim the outer bit, fix back, and check for air leakages.. This is done exactly the opposite way..

Which is right, Ishan..where are you??

[iraghava]

Originally Posted by headers

I thought One had the remove the tyre and put the sealant from inside, iron it , then trim the outer bit, fix back, and check for air leakages.. This is done exactly the opposite way..

Which is right, Ishan..where are you??

No Vikram, the current method is to remove the nail if any, use the plunger to make sure there enough space for the sealant to go in then put the sealant in the puncture & cut the excess bit from the top.

For an exact explanation, there is a pictorial coming up soon. so wait for that.

Originally Posted by hydrashok

The moment I saw the typo, I knew it was only a matter of time before you'd mention this

Looks like I'm getting predictable!!

[vishnuvijay]

oops guys, sorry about the 'nair' thing. i had cross checked my post before posting it, i don't know how i missed this.


iraghava, it was smaller than hydrashok.

[rks]

Originally Posted by vishnuvijay

hi guys, by the time i reached home, my dad had already changed the problematic wheel/tyre and put on the stepney/spare wheel and guess what, he had found a big nair on it. so hehehehe, the problem was a typical puncture.

If your tyre pressure came down from 30 psi to 11 psi in just 2 days it had to be a bad puncture. Normally nails will not cause such rapid leakage in tubeless tyres, unless the nail was stuck in for a long time and caused damage when you drove around. But there is still no explanation in that case for how you managed to do a 600 km long trip over 2 days without losing air. Possibly you measured the tyre pressure on the long trip while the tyre was hot and so did not detect much drop in pressure.

In any case always measure tyre pressures at regular intervals (say at least once in two weeks) when tyres are cold and secondly, when you already have a known problem of air leakage, solve it before embarking on long trips. Continuous fast driving on low tyre pressures (less than ~20 psi) can cause tyre damage and eventually, tyre burst. And do frequent visual inspection of your tyres apart from regular pressure checks.

I have found nails in my tyres on several occasions by now and at least on 3 occasions they caused punctures which I got fixed before any leakage happened. And on several other occasions, small nails were removed from my tyres without causing any puncture. I have now driven 12000 kms without any punctures on my Turanzas, but removed small nails on 3 occasions. Unfortunately right now road repairs are going on at several locations on the route to my company at Hadapsar (Pune) and I am expecting punctures due to nails/screws thrown on to the road by these guys.

[vishnuvijay]

hi rks, i usually check the tyre air pressure once in a month since the car is not driven frequently, but now i think i'll check it every 2 weeks.