I wouldn't worry about 47 psi cold as being "overinflated" or dangerous. That said, I want to make sure that you realize that you can easily let small amounts of pressure out until it is back down to exactly where you want it, right? A $5 tire pen gage will get you everything you need once you've inflated a bit over your target.
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Model 3 Tire Pressure
- Thread starter Stellavator
- Start date
You consider 50 a lot higher than 47?(Assuming mxm4 18")
Over inflating isn't too much of an issue. Are you using the TPMS for the reading or a tire gauge? The TPMS are not terribly accurate and will also get affected by warmer tires. You should check air pressure with a tire gauge with cold tires.
Yes, TPMS on cold tires was showing 47. Gauge from the air pump at the gas station was showing 40. You think the gauge is more accurate? I actually deflated - because when the gauge was showing mid 40’s TMPS was showing 50+.
TT97
Active Member
My TMPS is about 3 psi lower than tire gauge shows. I tried three different gauges (one of each type - stick, dial and digital) and all the showed the same psi - they could all three be wrong the same or my TMPS shows low.
Some TMPS-systems compensate for temperature. So they then give pressure as it would be for 18 or 20degr C ( 65 or 68 degr F) .
I dont knoq if Tesla also uses them
If you then fill to 47 psi when hot outside , the device you use gives 47 ( or % inacurate) , but TMPS in car gives lower.
When sensors are inside tire, the temperature given is exact, so calculating back is a piece of cake for the software.
I dont knoq if Tesla also uses them
If you then fill to 47 psi when hot outside , the device you use gives 47 ( or % inacurate) , but TMPS in car gives lower.
When sensors are inside tire, the temperature given is exact, so calculating back is a piece of cake for the software.
TT97
Active Member
Interesting, it had been summer when I was comparing the gauges to the TPMS, and even though the tire were "cold" it was still over 80* in my garage. I will need to check today now that it is winter and temperatures have dropped to the 60s*.
rtanov
Member
Also overinflating can cause the tire to wear more in the center as it bulges out due to the high pressure. So, if you are fine with that pressure monitor the wear to make sure that it is uniform through the section. 47 psi is too high for me - I am at 38 psi cold based on my previous experience and observations with the Model 3 - my primary goal is to optimize traction.
voip-ninja
Give me some sugar baby
I wish I could run 38psi. I get low pressure alarms if I run anything other than about 42psi once the temps drop into the 20's and 30's.
So If I understand this correctly, the reason the gauge is showing 40psi and the TMPS is showing 47psi is because I was inflating on a below freezing day, and the TMPS is compensating for the cold - showing me what PSI would be on a warmer day?
I was not aware that some systems compensate for temperature like that. How would it accurately decide what "cold" is for a certain region, I wonder? It isn't like there is an STP for tire fills... Logically, a system like this would imply that if I fill the tires to 45 PSI (TPMS indication) while cold, then drive around in the warm sunshine, the reported temp shouldn't vary because of this compensation for temp. And yet... plenty of experience shows me that the reported pressure can vary significantly from pre-down cold to mid-day heat.. So.... from my perspective, it is quite unlikely that Tesla employs this temperature compensation in reporting, and nobody should rely on it. You want to fill when it is cold *for your area* - not to some ideal standard that makes no since for your local temps.
I don't believe this is true, no. I think that the TPMS system just isn't all that accurate.... which is too bad, considering how simple the devices are, and how expensive they are.
SageBrush
REJECT Fascism
My winter tyres are outfitted with German (supposedly top rated) aftermarket TPMS. They show pressures 3 psi less than my digital gauge checked manually.
rtanov
Member
I don't think the Model 3 TPMS compensate for temperature - I can see the reported pressure go significantly up as the tires warm up due to prolonged driving.
Yeah, that warning is annoying and not very consistent in my view. I've found that 38 psi at around freezing temp only occasionally triggers the warning and it eventually clears up. They need to lower this to 35 psi max.
MacGreiner
5YJ
voip-ninja
Give me some sugar baby
I agree and don't know why they are so obstinate about this.
It's worse if you live high above sea level, because then the TPMS is also off for that.... it treats the tire pressure as if it's at sea level and ignores that real tire pressure that is read with a meter at 6,000 feet above sea level.
They could either make TPMS altitude aware by using the car's GPS or they could just lower the pressure warning for those of us who want a more compliant ride and live somewhere above where Venice Beach is.
I don't know if its the Tesla specific sensors, or just their interpretation of the data, but it is quite bothersome. A month ago during a few colder than average days tire pressure dropped under 40 and I got constant LOW warnings. The annoying part is that the warnings were for tires that were at 39, while others were at 38 and had no warnings.
The last update seems to have fixed that.
Now on an unseasonably warm day after a highway trip they are showing 47-48, which I would normally consider over-inflated. My cheap tire guage puts them at 43 max.
The last update seems to have fixed that.
Now on an unseasonably warm day after a highway trip they are showing 47-48, which I would normally consider over-inflated. My cheap tire guage puts them at 43 max.
TT97
Active Member
My old car would allow me to "reset" the ideal. For example, if I wanted my tires at 32 psi, I could inflate them all to 32 and then set the TPMS. It would then warn you if you got x% below your set psi of 32 (I think it was 20%).
Tesla needs to implement something similar especially with Elon suggesting 39 psi for comfort.
Tesla needs to implement something similar especially with Elon suggesting 39 psi for comfort.
It shouldn't be that hard, just have setting for comfort, average, and efficiency. The car can even talk you through more or less air per tire..
follow.johnny
FSD Beta Tester
I have my tire pressure set at 44 PSI cold for my 19" Sport Wheels. No issues with affecting comfort and efficiency.
No more low tire pressure warnings in the morning as well. Located in Socal.
No more low tire pressure warnings in the morning as well. Located in Socal.
If you see the pressure go up when tires warm up by driving, then it is not a compensating TMPS.
But the high pressures for electric cars ( and bycicles) is done for more actiradius.
For savety, so your tires wont overheat,when driving the speed the pressure is calculated for, you probably can do with much lower pressure.
Dangerous estimation 35 psi for speeds of 99mh.
I am able to calculate it for you, need weight on wheels, max speed used, and tyre-specifications
But the high pressures for electric cars ( and bycicles) is done for more actiradius.
For savety, so your tires wont overheat,when driving the speed the pressure is calculated for, you probably can do with much lower pressure.
Dangerous estimation 35 psi for speeds of 99mh.
I am able to calculate it for you, need weight on wheels, max speed used, and tyre-specifications
goldengate
Member
My door panel says 42 psi, service center just inflated them to 45-46.
I've read through this thread... seems like 42 is comfort, 45-46 is range... I'm taking a long car trip so I guess I should leave them at the 45?
I've read through this thread... seems like 42 is comfort, 45-46 is range... I'm taking a long car trip so I guess I should leave them at the 45?
Set the pressure at whatever makes you happy (within a reasonable safety envelope). Want range, go high. Want comfort go low. Want a compromise, go somewhere in the middle.
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