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[Guynamedsean]

my rear right tire is losing about 5psi per day. I run the original run flats on the original 135 rims. Is this most likey a tire problem or could it be a cracked rim? I would hate to buy 2 new rear tires then find out I got a cracked rim.

FYI - the car is 5 months old. I bought it new in September 2010. THe problem just started a couple of weeks ago. I have been filling it up constantly.

[Tom K.]

Most likely a nail in the tire. Take it to a good tire shop and if the puncture is not near the sidewall, have it repaired. Note that your BMW dealer will probably tell you that RFTs cannot be plugged or patched, but plenty of folks have successfully had them repaired.

Tom

[texasmojo]

I had a similar problem with my aftermarket rims and tires. I checked and checked for nails and nothing. Went to a local tire shop and they dismounted tire and cleaned the inner lip. Problem solved. Sometimes tiny dirt particles get in between the seal.

[emac08]

Originally Posted by Tom K.

Most likely a nail in the tire. Take it to a good tire shop and if the puncture is not near the sidewall, have it repaired. Note that your BMW dealer will probably tell you that RFTs cannot be plugged or patched, but plenty of folks have successfully had them repaired.

Tom

yup. exactly what he said.. take it to a place where they inspect and patch for free. problem solved. pepboys did it for me as well as americas tire co did that for my gf with her runflat.

[fboutlaw]

Ironically, I have the same problem on my stock wheels. Went to firestone today nearby to have it repaired, they couldn't find anything wrong. Really weird and I won't trust that set of tires again.

How you can self diagnose the issue is set up a kiddie pool. Set the tire to high pressure. Dunk it and look for bubbles.

[VMRWheels]

It could be some kind of puncture in the tire, bend, crack, or pinhole leak in the wheel. I would do a dunk test to see where its losing air.

-Charles@VMRWheels

[allies_jh]

Make sure that you take it to a shop that's competent enough to do Run Flats. I made the mistake of taking it to a place that wasn't super good at it and they damaged my wheel. They fixed it, but it was a pain in the ass.

[Dackelone]

OP - you should also check the valve stem. The 11mm nut around the stem tends to back off. It should be just snug - very little torque. I think it is something like 3.5Nm But you can run a search and check on that.

Quite a few people have had the valve sten nuts back off - causing a slow leak. You could always take some soapy water and spray it all over the valve stem area.


Dackel

[stevenc]

Loose valve stem, happened twice to me.