Recommended tire pressure too high

[jamnmon66]

I just swapped out of snow tires back into the stock tires (or attempted to) on my LR RWD 3 with 18" wheels and the guys at Discount Tire showed me the two that must have been on the rear were too worn to be safe. The other two still have a lot of life left. I think I only had 12-13k on them when I put the snow tires on. Disappointing for sure but I have a lead foot and I'm absolutely addicted to the torque so I can only blame the car for being too much fun to drive.

I've always been surprised & doubtful about the recommended tire pressure at 45psi and this was confirmed because the tires were very worn in the center of the tread but not very worn at all closer to the sidewall... an obvious sign of over inflation. I should have taken a picture but I didn't think of it until later.

I remember a chalk trick from my Jeep days to figure out the best pressure for over sized tires. The thing to do is to get some chalk and go to an empty parking lot with brand new tires mounted. Then draw a line across the tread and drive a short distance and see where the chalk wears off. If you play around with different tire pressures then you can figure out what pressure range wears the chalk evenly. That should also be the pressure range that will have the best contact patch and, in theory, will be the safest and will wear the tires out evenly.

Anyway, I did this the other day with my brand new set of Pirelli P Zero Neros & the range I came up with was 34-38psi. My wife also has a LR RWD with 18" wheels and she has less than 2000 miles on the stock Michelins. I did the same procedure on her car and came up with the same answer. I plan to set the pressure at 38 after driving for a while so that will be the "hot" pressure. Then I'll let them cool and that will be the -"cold" pressure which is what we're all used to checking. My guess is that it will land at 35psi but I'll check back in once I have that figured out. BTW, I have a high quality pressure gauge and it's a couple of psi off of what the tpms says on both cars.

When I bought the car, I did the math and I figured out that tires are going to cost more per mile than electricity (my off-peak rate is only 5.9 cents per KWH). But I was guessing 30k miles for a set of tires. This is much worse than expected but I'm guessing that I would have gotten closer to 20k or maybe more with proper inflation & rotation. Given that tires are more expensive than "fuel" I'm more than willing to sacrifice a little range to extend the life of the tires.

The upside is that the car rides noticeably softer & smoother even with the sporty summer tires on it. I haven't done any "spirited" driving yet but I expect to have a lot of fun with the new tires. I set the two that are still good aside for my wife's car so it won't be a total loss.

 

[lmmo]

Recommended is 42 psi, or a bit lower if you prefer a more comfortable ride.

 

[jamnmon66]

Recommended is 42 psi, or a bit lower if you prefer a more comfortable ride.

I remember that from a discussion in here and some tweets from Elon. But the pressure on the door jamb says 45. I was running low 40's with the snow tires. Can't remember if I dropped it to that last summer.

 

[nvx1977]

@jamnmon66 are you not getting a nag from the car about tire pressure if you have them as low as 35psi?

 

[VQTRVA]

I remember that from a discussion in here and some tweets from Elon. But the pressure on the door jamb says 45. I was running low 40's with the snow tires. Can't remember if I dropped it to that last summer.

Door jam says 42 psi for me.

Is it different for each M.3?

 

[jdcollins5]

I have a LR-RWD with 18” tires and my door jamb pressure is 45 psi.

 

[Insight75]

Would be great if you can adjust the "nag" so you don't see the message when lowering the pressure. I agree that the the recommended pressures are too high. I like to be around 38.

 

[Dangerous Fish]

Does the TPMS not re-calibrate when you reset it (or can you not reset it)?

Surely it's not factory set at a certain pressure? It should be monitoring pressure drop from a pressure the owner can set.
I'm assuming the higher than normal pressure recommendations are in order to get more range?

 

[flashflooder]

I run mine at 45psi (cold) and while my tires are wearing out fast (the rear, mostly), they are wearing out evenly.

 

[Msjulie]

Back in the old days of Model 3 (like my 2018 Jan LR RWD) 45 was the value, some thought the ride was too harsh so apparently it was changed (among other things). My 2018 August car shows 42 as the spec.

My car running OEM 19" wheels / tires is set to cold pressure of 45. No unusual wear but I also did have the alignment fixed a couple months back due to an ever so slight drift to the left.

I should note I always tend to run my tire pressures a little bit higher, I'm more interested in whatever small range increase I might get and the slightly firmer more responsive ride that comes with mildly higher pressures... in this car, I can feel when they are too inflated, the car suddenly becomes much rougher riding and handling sharpness drops.

YMMV

For those that noticed, yes this stealth performance car came with 18 but I swapped them out for OEM 19s

 

[TT97]

Does the TPMS not re-calibrate when you reset it (or can you not reset it)?

Surely it's not factory set at a certain pressure? It should be monitoring pressure drop from a pressure the owner can set.
I'm assuming the higher than normal pressure recommendations are in order to get more range?

Tesla recently introduced the ability to set your preferred settings. It may be in version 2019.12.

 

[jmaddr]

I've thought the same. Only two trade-offs I could see.
1. Reduced range. Lowering the PSI on a heavier car such as ours will likely increase the rolling resistance, leading to increased KWpm.
2. Sidewall rollover - reduced traction. Coming from a HPDE background, I could see a greater potential for sidewall rollover at lower pressures, especially with our heavier cars. The same jeep trick you mentioned above across the tread is used in the HPDE and racing communities too. However, we extend the chalk line all the way over the sidewall to about 1/2 way. Then go out and drive it like you stole it and see how much of the chalk gets wiped off. If the chalk on the sidewall, and I mean even on the outer edge of the tread block, wears off, you are rolling the tire over one to the sidewall on aggressive cornering and that leads to reduced traction. Now, this is more important in a HPDE than a daily but it is a concern for some (maybe if you drive aggressively, live near nirvana roads like canyons, etc). If you want more high tech and have an infrared thermometer, run it at different pressures and go do a normal route. Use the infrared thermometer to make sue the tire temp is the same across the width of the tire. Camber affects this number so be careful interpreting the results.

 

[jerry33]

If you want more high tech and have an infrared thermometer, run it at different pressures and go do a normal route. Use the infrared thermometer to make sue the tire temp is the same across the width of the tire. Camber affects this number so be careful interpreting the results.

Bear in mind that tires heat up very fast after stopping, so it's best to have a helper waiting with the thermometer and taking the measurements.

Another thing is that the vehicle placard pressure is based on a set of assumptions. If your driving conditions are different from the assumptions the pressure needs to be changed. Usually track pressures are much lower than street pressures because tire life and energy usage aren't a consideration--only lap times. And off-road driving is totally different from on road driving.

Something else to consider is that accidents are more likely in unfavorable conditions. So, for example, hydroplaning occurs when the pressure in the wedge of water that builds up in front of the tire is equal or greater than the inflation pressure. So lower pressures increase the risk of hydroplaning.

Then there is also pothole damage. Higher pressures are your best defense against tire and wheel damage from potholes.

 

[realvvk]

I just swapped out of snow tires back into the stock tires (or attempted to) on my LR RWD 3 with 18" wheels and the guys at Discount Tire showed me the two that must have been on the rear were too worn to be safe. The other two still have a lot of life left. I think I only had 12-13k on them when I put the snow tires on. Disappointing for sure but I have a lead foot and I'm absolutely addicted to the torque so I can only blame the car for being too much fun to drive.

When I bought the car, I did the math and I figured out that tires are going to cost more per mile than electricity (my off-peak rate is only 5.9 cents per KWH). But I was guessing 30k miles for a set of tires. This is much worse than expected but I'm guessing that I would have gotten closer to 20k or maybe more with proper inflation & rotation. Given that tires are more expensive than "fuel" I'm more than willing to sacrifice a little range to extend the life of the tires.

Anyone who has owned a heavy, powerful RWD car will tell you that you are lucky to get 12-13k miles out of a set of tires. My 360 hp BMW 550i will consume its 275/30-19 rear tires in about 10k miles, maybe slightly more if I drive slow and in a straight line. And the tires are worn in the center as you describe. Recommended tire pressure is 42 psi.

Gotta pay to play...

 

[TheWalkingDad]

I took my tesla to the service center to fix some wind noise they did an overall check and inflated my tires to roughly 46 psi to meet spec as they quoted. About a couple months later I was in the same service center for a drive stalk issue and a rotation. After rotation they deflated my tires to 40 psi. Could be because summer vs winter ?? I got pretty much even wear at 45 psi so I’m not sure why they did it.. For rotations they also only do front to rears and do not cross. I Have a LR RWD.

 

[EfficientWatts]

I have a Model 3 AWD. Sticker says 42 psi on the door jam.

Using a tread depth measuring tool, I've noticed slightly more wear on the middle versus the sides. The difference is 1/32" or less, but it sticks out because I can barely see the yellow on my tool vs just not being able to see the yellow on the sides. These are just the rear tires.

Unfortunately I have no idea what they were set to when delivered. It was very possible they were over-inflated on delivery so I could have been driving with a much higher psi and not known it for a while.

As such instead of refilling to 42 psi I've only refilled it to 40 psi. With summer temps and such coming up I think I'll be set, and Elon said that ~39 would be fine anyways so I think I should be ok.

It did make me wish I had done tire rotation at ~6250 mi. I was able to get away with not doing them as often with my Prius but I don't think I can with this car due to how fast they're wearing out.

 

[Uncle Paul]

On RWD, tire life can be extended by rotating your tires front to rear. The fronts tend to wear more on their edges because they are used for steering but not propulsion. The rears tend to wear more in the center, especially if you have a lead foot.

Cornering agressively or accelerating rapidly will of course cause more rapid wear.

Lowering tire pressure will give a smoother ride, but decrease efficiency and increase wear. Optimizing tire wear takes concerned attention.

 

[jerry33]

Anyone who has owned a heavy, powerful RWD car will tell you that you are lucky to get 12-13k miles out of a set of tires. My 360 hp BMW 550i will consume its 275/30-19 rear tires in about 10k miles, maybe slightly more if I drive slow and in a straight line. And the tires are worn in the center as you describe. Recommended tire pressure is 42 psi.

Gotta pay to play...

Last set of tires on my S85 RWD, lasted 42,000 miles and I actually took them off a bit early because I was going on a trip. 12-13K miles for high performance tires is still a bit low (unless you are running race tires with a DOT marking, yes there are tires like that, in which case it's very good indeed).

 

[jadatis]

Pressure advice for electric cars are given extreme high for reasons of high actiradius of battery.
Because of the tires being still oversised for the higher weight, safe lowest pressure is probably about 30 psi.
Now you can sooner go higher without centrewear then lower without sideswear, but also that has an end, and you experienced that with 45 psi》centrewear.
The 30 psi , I estimated, is completely save so no overheating of any part of tire, when driving high speed.
But more energy loss by the tires.
Once determined that normal calculated pressure makes at 50mph about 25% of " fuell-consumption, read energy use.
Will make a rough calculation.
Going to 45 psi gives 30/45is 2/3 times as much surface on the ground, so surfacelength( not totally in this case, alo widt gets less) . This gives square 2/3 as much deflection of tire is 45% op heatproduction so energy loss.
45 % of 25 % is 11.25 % .
30 psi 25 parts of tires and 75 parts of the rest.
45 psi 11.25 parts of tires and 75parts of the rest is total 86.25 % of energy use of 30 psi.
So when battery is empty at 200miles at 30 psi, at 45 psi there is still 13.75% left in battery, wich takes you another 31miles
So you can savely liwer the pressure for comfort and even wear, but it costs you actiradius.
But let me first calculate that lowest pressure for you, if my estimation of 30 psi is to low you risk tiredamage and blowing tire, and that is worse then centrewear.

I just swapped out of snow tires back into the stock tires (or attempted to) on my LR RWD 3 with 18" wheels and the guys at Discount Tire showed me the two that must have been on the rear were too worn to be safe. The other two still have a lot of life left. I think I only had 12-13k on them when I put the snow tires on. Disappointing for sure but I have a lead foot and I'm absolutely addicted to the torque so I can only blame the car for being too much fun to drive.

I've always been surprised & doubtful about the recommended tire pressure at 45psi and this was confirmed because the tires were very worn in the center of the tread but not very worn at all closer to the sidewall... an obvious sign of over inflation. I should have taken a picture but I didn't think of it until later.

I remember a chalk trick from my Jeep days to figure out the best pressure for over sized tires. The thing to do is to get some chalk and go to an empty parking lot with brand new tires mounted. Then draw a line across the tread and drive a short distance and see where the chalk wears off. If you play around with different tire pressures then you can figure out what pressure range wears the chalk evenly. That should also be the pressure range that will have the best contact patch and, in theory, will be the safest and will wear the tires out evenly.

Anyway, I did this the other day with my brand new set of Pirelli P Zero Neros & the range I came up with was 34-38psi. My wife also has a LR RWD with 18" wheels and she has less than 2000 miles on the stock Michelins. I did the same procedure on her car and came up with the same answer. I plan to set the pressure at 38 after driving for a while so that will be the "hot" pressure. Then I'll let them cool and that will be the -"cold" pressure which is what we're all used to checking. My guess is that it will land at 35psi but I'll check back in once I have that figured out. BTW, I have a high quality pressure gauge and it's a couple of psi off of what the tpms says on both cars.

When I bought the car, I did the math and I figured out that tires are going to cost more per mile than electricity (my off-peak rate is only 5.9 cents per KWH). But I was guessing 30k miles for a set of tires. This is much worse than expected but I'm guessing that I would have gotten closer to 20k or maybe more with proper inflation & rotation. Given that tires are more expensive than "fuel" I'm more than willing to sacrifice a little range to extend the life of the tires.

The upside is that the car rides noticeably softer & smoother even with the sporty summer tires on it. I haven't done any "spirited" driving yet but I expect to have a lot of fun with the new tires. I set the two that are still good aside for my wife's car so it won't be a total loss.

 

[SDKoala]

Mine OEM tires got down to 3/32" after 10K. They were rotated exactly once at around 4K miles when I had one patched for a nail. Did a lot of reading here and other forums and came to the conclusion that this is not the norm, even among spirited Model 3 owners. I'd also think there be a rash of people complaining about having to replace their tires after such little mileage if that was the case. I have a 3/2018 build and the door plaque says the original recommendation of 45 PSI, which is where I've kept it to maximize range. I didn't ask about the wear pattern, but now now I wonder if that could have also contributed to how quickly they needed to be replaced. This is a cost of ownership that I didn't figure and wasn't expecting to need new tires yearly.