I recently bought a pair of Kuhmo Ecsta SPT's (see thread). I bought them from tirerack.com and had them installed at a nearby shop. On 2/19 (exactly two weeks ago) I inflated each tire to 34 psi. I did a check today and the left tires are at 30.5 psi, whereas the front right is holding fairly steady at 33.0 psi and back right at 33.5 psi. I'm using a digital pressure gauge which is accurate to the nearest 0.5 psi.

I don't see any nails or whatever in my left tires.

Does this sound like it is a problem with the tires, or with the tire installation? I'm afraid I don't know much about either. It just seems strange that both lefts are losing pressure. What do you recommend I do about this?

Thanks as always

 

Hmm. Hard to say. I would re-inflate all to 35 and run it for a week or so. Check it again if the left side is off again take it back to the shop. If its the tires you wouldnt expect more than 1 to be defective I would think.

I have had times when 2 of my tires are off from the others, its just random and strange.... Why its always a good thing to check your tire pressure regularly I suppose. I have the kuhmo's as well.

 

Have you checked the TPMS sensor valve stems for leakage?

 

Um, no I haven't. At the risk of sounding stupid (no, actually I think there's no risk here...oh well), how do I check?

 

take some soapy water and run it over the valve stems. If it starts making bubbles you have a leak.

Of course it works best if the stems are closest to the ground but don't need to be.

I have had the tires replaced and one of the stems was leaking. I don't understand why they had to mess with the stems.

let us know what you find out.

 

If it's a slow slow leak the soapy water test might not reveal enough and sometimes it's not the rubber leaking (around the valve stem) but the valve inside the valve stem - it can stick/get some foreign matter in it and leak slowly. Try replacing that valve, you can get them at any auto parts store.

 

it could be a ripped bead, when they installed it.

 

All of the above reason are possible. The most common issue with new tires loosing air pressure on a TPMS vehicle is the valve core itself as spin9K said. You can buy a four pack at most part stores for a few dollars. If you used a corner garage type shop rather than a "big box" type of shop like a Goodyear or Firestone store you may have a torn or rubbed bead. Larger corporate shops tend to use newer and safer equipment where as small mom and pop type shops normally don't replace their equipment until they need to. This mean they may have the old metal tire horns which tend to pull and tear the bead if they are not saturated in lubricant constantly. The newer styles of machines have a coating on the horn that allows the tire to slide over the horn without resistance which greatly reduces the chances of damaging the bead.

 

Why is it that no one mentioned cold whether?

A cold garage floor or cold ground will make your tires loose pressure.

I would fill them up again and drive for a few days.

Also the TMP sensor is suppose to go off if there out of sync by 2 lbs.

Check the maual for the exact value.

 

Man, you guys are incredible. Thanks all to your input and advice - it is much appreciated! I gotta say, I feel like a dumbass but I checked my tires again in a parking garage, and it was the same thing (left side was low). But I got suspicious, since the car was leaning in the same direction (sloping towards the left tires) - and, why BOTH left tires? That's an awfully strange coincidence. I tried measuring on level ground. This time, the pressure was about equal. Well! So, I'm thinking it is actually okay. What is surprising to me is, if the car is sloping towards the left tires - that is, the left tires are lower than the right tires, wouldn't you think the left tires would have more weight on them and hence more pressure? I think it's strange that the right tires showed a higher pressure reading. But, I guess that is just how the suspension handled it, or something. I'm still surprised.

To me an analogy is, you are standing on a hill (skiing, perhaps). You put all your weight on your downhill ski. Or, rather, for this example, try to stand evenly. Which foot is more likely to carry more of your weight - your foot that is downhill, or the foot that is uphill? (Anyone who's ever skied/snowboarded would say) downhill of course! So. weird. But it seems - and I'll check again tomorrow - that all is well. Thanks again, that's why I keep coming back to this place

*Edit*: Oh yeah, and it was cold out both times, but, I'm not sure why that would affect one side more than the other...