Hey guys I'm wondering if anyone else has this problem if so how'd you fix it or deal with it...
So basically the past 2 mornings when I've went to leave my psi in the rear tires have decreased since the night before. Yesterday morning they were right around 20 psi! And then this morning they were at 28ish which I can understand sorta. I filled them up yesterday to 34-35 psi the front tires aren't really fluctuating drastically like the rears are though..
Temperature story: I live in north central Florida and the day before yesterday it was around 80 degrees and then 60ish yesterday morning when they were at 20 psi. And then about 80 ish degrees yesterday and back to around 60 this morning and they were at 28 psi this morning they heated back up to 31 psi by the time I got back home from taking the gf to work.

Is this just because of the rapid temp change or is it something to be more worried about? I have a little electric air pump, I may have to just wake up 15 mins early every morning and fill em up but that seems kinda ridiculous..

Does anyone else have this problem? Btw again its only the rears the front tires aren't changing as much they are going to right around 30-32 and heating back to 34ish in a mile or two. Also I have the OEM size tires staggered fitment but I got new tires from a tire shop here in April and are the milestars if that info helps any.

 

it happens to all of us, if you want to eliminate it go to Nitrogen in your tires. most of the time it isnt that drastic of a change though, usually only a couple pounds tops.... i would check for leaks or maybe a nail or something in tires, you might also need a tpms rebuild kit (aka new o-rings)

 

Thanks trav.

It's funny cause I was thinking about the nitrogen thing on the way to the gfs work today but didn't know if it make much of a difference.

Maybe I just need new tpms? I know I have one out on one front and one rear which is why I check the psi very often. When I seen the low psi I checked for nails or noticeable holes and found nothing.

But from what you said the fronts definitely seem fine then cause they are right in that range, but would you think that both rear tpms are bad (or the washers?) And the fronts are fine then? Seems kinda weird to me cause usually things don't go out together at the same time... But maybe the cold just makes them noticeable now too though?

 

o-rings can dry rot, have a small tear.... who really knows. i would also check the valve stems

 

I was thinking the valve stems are possibly the problem. But how would you check that? Is there a way to just look and tell or do you have to remove them? If you do have to remove to know how do you tell if its bad or good? I've never had a problem with valve stems before and this is my first car with tpms. My problem was always hitting nails with my other cars lol

 

if they are lose they will lose air pressure

 

Well that's simple, way to make me feel dumb... LOL ill have to have my friend bring his valve stem remover over.

So then would say if that's not the problem that I should get new tpms or a rebuild kit?

 

wouldnt hurt, going to be a process of elimination unfortunately

 

Yeah sadly. Hopefully its just the valve stems if not at least the kits aren't to expensive but I think if its not the valve stems ill just get new tpms instead of wasting money and hoping when I know I need a couple anyways.

But thanks for the help and reassurance trav.

 

You might fill the tires with 40-45 lbs of air and then spray Windex or some other soapy liquid around the valve stems and the bead. If there are any leaks, you should be able to see bubbles forming. I would not remove the valve stems before checking with the soapy liquid. The TPMS is attached to your valve stems. If you can find nothing, I would take the car to a repair shop and have them take a look at your tires.

 

Lol I was literally just looking around the house for some but I have no Windex and only a few drops of dawn left. I'm probably about to just put it in a spray bottle with a little water and start spraying around. But honestly wouldn't it leak out a bit faster if that was the problem? I would think I'd wake up with a near flat. And that wasn't the case at least for this morning. And even after the trip the psi did go up I would think it would go down more than 5 psi ish over night with the cold change too

If it is leaking it is veryyy minimal.

 

As mentioned, you may have a leak.

Best time to fill and set tire pressure is morning before the car has been driven and the sun has not been beating down on the tires if you park outside.

Also set pressure to 35psi

 

Didn't read everything in the OP or this thread but it sounds like you have a slow leak. Tire pressures fluctuate depending on ambient temperature but should only do so within a given window, never just in a single direction. The pressure also fluctuates until it reaches a lower/upper limit, where it will stay. If you have to re-inflate in a matter of days then you have a leak.

The best way to find any leak is for you to take the wheel off and submerge the entire wheel/tires combo under water. If you see air bubbles, then you know there's a leak. Even if it passes this test, I'd maybe consider remounting the tire so the tire is seated on the wheels properly and that a new valve stem is used.

 

Well if the leak can happen for days and not be noticeable for awhile then that's probably what it is.

Terra, that is exactly what I did. I pulled out of the yard and noticed psi was 19 the one morning so I slowly drove less than a mile to the store and filled all 4 to 34-35 so I didn't risk missing anyone other low ones besides the one I seen at 19. This was right at 7 am before the sun peeks up at all

Three,
I believe the wheels are eated properly, Idk if you guys have heard of them, but they were Installed at RNR they are quite professional and I never had a prob with them before and haven't heard anyone else ever having a problem with them. I will be getting some windex most likely and checking for leaks. And will replace the valve stems if I find it to be the leaking area

 

I just made a soap and water concoction and sprayed it all over the valve stems didn't see any bubbles or nothing so Idk. With that ruled out could it still be caused by the tpms?
I'm starting to think maybe it was just caused by the cold weather but still, that's a pretty big difference.

Any other ideas guys?

 

Im assuming since you say the PSI is low you check cause the tire LOOKS low.
Correct?

Also how are the milestars plan on picking them up as temporary tires for stockies while I pick up new wheels.

 

It could be leaking somewhere on the tread, which is why submerging the entire wheel/tire is the best method and why I recommended it.

 

No I checked because the dash said the rears were at 19psi and then I checked them and could push them in a but so knew they were definitely low at that point.
The milestars seem pretty good in my opinion they have decent grip but will still allow you to spin them good. I've done numerous burnouts and put about 14k on them so far and the tread still looks like they are brand new.

Edit- I've had them for around 6 months and the z is my dd, they have held up very well.

I want to do the submerging technique cause that's what I've always done growing up but I don't have anything big enough to put water in that they would fit in :/ if they seem like they are still getting too low I will have to take it somewhere and get them checked out, sadly, will be a waste of money for something I could do myself :/

 

^^ But… You do want to do this (going to a tire dealer) so it gets fixed. The rear tire pressures you report are dangerously low.

 

Yeah I agree they were crazy low, I'm just lucky/thankful I noticed it before I drove anywhere...

I drove around 200 miles the day before the morning of the super low psi, could that maybe have caused it? It was pretty hot that day, and it got really cold that night. I personally dont think its the cause but its more info to work with...