vandal1x

for no reason i keep getting low tire pressure.all of a sudden the tmp shows low pressure(in two differnt tires now). when i go to fill it up its only got 20 psi and its suposed to be at 50. why am i lossing air all the time? never had this problem with regular tires.

kscarrol

If you refill them to 50 psi and they go back to 20, you've got a problem. Have you looked for a nail in the tires? Just had a RFT replaced on my wife's X5 for just that. Tire was slowly losing air and sure enough, there was a nail.

EBMCS03

Ya you probably have a nail in there... I know run flats are bad... but thats only in terms of comfort not how it holds air. theres no way it will go from 50 to 20. and if you're filling your tires with 50psi you have another problem there. dont exceed 42psi.

alexnyc

you can't keep getting low pressure for "no reason",the reason is obvious-your tire(s) has a leak or it's leaking from the rim(i am not trying to be wise guy),sometimes the source of leaking is hard to pinpoint as in the case of very slow leaks when you can't see it bubbling even when the tire is submerged in tub with water,then you have to carefully inspect the rim for cracks-it happens qiute often.Go to tire shop and have them deal with it,but do take of it.Good luck!

kscarrol

Good point on the cracked rims, failed to mention that possibility. It is not unheard of...

vandal1x

its not the same tire,one tire was low one day so i filled it up. havent had a problem with it again. i filled it about 2-3 months ago.then today a different tire was low at 20 psi (i think the tpm doesnt let you know the tire is low untill it gets that low)again i filled it and so far so good.i looked for nails and nothing im not that dumb i think its weird that the same thing has happed to two different tires. and i dont mind the run flats i just dont like that this keeps happening. anyway my wife is taking the car to the dealer tomorrow and ill tell her to have the check for cracked rims and what not. again thanks

EBMCS03

2-3 months? Yikes! I hardly go 2-3 weeks without checking my tire pressure.

BigLew

For goodness sake stop filling your tires top 50 pounds man.

Russ1974

Checking for nails isn't as easy as it sounds. You can't just "have a quick look". The nail could be dark in colour and could have penetrated right in to the tyre. You really need to get it checked out as others have said. I picked up some nails on a motorway trip and it hit both rear tyres, again there was nothing visible to me but there were actually multiple nails in _each_ tyre. If they are on the inside, you won't be able to see them unless you get right under the car with a torch. But ultimately if they are losing pressure and coming up with a warning, there is a problem - I certainly wouldn't even consider just pumping them back up and "seeing how they go". They have lost pressure for a reason ... fix the problem, not the symptom!!

JStraw

I am sure a lot of folks are wondering why you are filling up to 50psi. Maybe there's a reason for it, so could you please let us know why??

You may/may not have a nail in the tire, but going 2-3 months without checking pressure is probably too long. RFTs are know to loose pressure over time unlike regular tires. You should check the pressure more often. I find myself going 3-4 weeks before checking at I am down at least 3-4 lbs in some tires, not all. And it's not always the same tire.

Cheers.