Tire Losing pressure daily.

[Iylia H]

I'm currently running on 245/40/18. And the left rear tire seems to lose pressure everyday. Only that tire. It will definitely lose 10psi per week.Brought the car to a tire shop. They checked for any leaks. They did everything, from soaking the tire in a tub of water, and using soapy water to look for any leaks. And there was none.No puncture, no tire seal leaking.. No nothing.But the problem still persist. So I was wondering, what could be the problem? Anyone have encountered this before?Need help ASAP.

 

[B33mEr]

Could be the valve is faulty or your wheel barrel have developed a hairline crack. Did the tyre shop take off the tyre and inspect the wheel?

 

[pussy]

change the tyre, ask someone to lend one, if leaks, then the rim, if not then tyre... no rocket science here...

if not, you will running circles and wasting time and money....

 

[David Yong]

what cud be possible problem with the rim and how to rectify it?

 

[jarance]

what is the tyre pressure setting for your rear tyres?

 

[Iylia H]

change the tyre, ask someone to lend one, if leaks, then the rim, if not then tyre... no rocket science here...

if not, you will running circles and wasting time and money....

could be it, anyone with 245/40/18 tire running around anywhere which i can borrow for this test?

what is the tyre pressure setting for your rear tyres?

They are running with 39psi.

 

[YaZmEeN]

39psi is too high i guess bro, mine riding at 36psi, 19" size.

another option for u is go to the other tyre shop, which is bigger and has better facilities to check. second opinion might help

 

[Iylia H]

39psi is too high i guess bro, mine riding at 36psi, 19" size.

another option for u is go to the other tyre shop, which is bigger and has better facilities to check. second opinion might help

I got this pressure from an e34 M5 handbook which states;

245/40 ZR 18 = 41 (front) 43 (rear)

With load

245/40 ZR 18 = 46 (front) 50 (rear)

I put 39, for comfort.. and my car, not having the heavy m5 engine.

 

[ICEMAN 68]

what cud be possible problem with the rim and how to rectify it?

a small hairline fracture/crack ... how to rectify it ...you need to bring your wheel to a good wheel recond shop and they will some how use some sort of "DYE" purple in colour and will apply to some of the suspected point which may be seen to have a hairline fracture/crack ... i believe it's the same method used to detect a hairline crack on cyclinder heads due to overheat ...

 

[Eggie86]

Losing 10PSI a week sure is too high bro.

Hope the problem will be rectified soon.

Btw, 39psi sure is kinda high.

 

[saat]

That much pressure loss can only be the result of a leak.
The leak can be at any one of he following:
1. Tyre
2. Inflation valve
3. Rim

You mentioned having gone to a shop and found nothing. Impossible that they cant find anything. Even the slowest or smallest of leaks (say from a hairline crack in the rim) will still show up as bubbles if you wait long enough. A hairline crack in the rim may only show up when the rim is hot and/or loaded.

Before jumping to conclusions and doing drastic things (like changing tires), I suggest you take it to another tire shop and have it checked again.

 

[David Yong]

i am running on 19" and my tire pressure is 30psi front and 32psi rear. To me, anything higher than 32psi is very very uncomfortable.

 

[affan66]

putting the tyre in the water tub sometimes doesn't show the leak because the tyre is not loaded. When the tyre is on the ground and with the whole car's weight on it, air will leak.

Another possibility is that the inside of the rim is dented. So, again, when the tyre is loaded, air leaks out.

 

[Iylia H]

i am running on 19" and my tire pressure is 30psi front and 32psi rear. To me, anything higher than 32psi is very very uncomfortable.

works fine with me on my 34, as long as im within the range specified by the original BMW handbook for 245/40/18...i tried going lower, there'll be some sort of cracking marks on the outer part of the tire...

as of the current situation now, brought it to a tire shop... they painstakingly brush the tire with soapy water...and found a very minute hole... when i say very, it is very very small... so plugged it.. will see how things go