TPMS on non factory wheels

[gt2690b]

i am always getting a low tire pressure warning but i have aftermarket 18s so i do not need to run 42 psi according to tire psi calculator:

OEM Size (255/45R19 SL) Load Capacity: 1764 lbs. @ 42 psi.

New Size (235/55R18 SL) Load Capacity: 1764 lbs. @ 36 psi.

so is there a way to tell model Y to chill on the low tire pressure?? i want to be warned at like 32 psi or something (not 38ish like now)

 

[jjrandorin]

Did you reset the wheel size and / or the TPMS? I hate to sound like a stereotypical forum regular on any forum and say "its in the manual, have you checked there?".... but resetting the TPMS and changing the wheel size is in the online manual.

https://www.tesla.com/ownersmanual/modely/en_ie/GUID-94F63B13-EA2C-45D9-83AB-5DCA6295D587.html

 

[gt2690b]

Did you reset the wheel size and / or the TPMS? I hate to sound like a stereotypical forum regular on any forum and say "its in the manual, have you checked there?".... but resetting the TPMS and changing the wheel size is in the online manual.

https://www.tesla.com/ownersmanual/modely/en_ie/GUID-94F63B13-EA2C-45D9-83AB-5DCA6295D587.html

Yeah well 18" wheel is not an option.. I did switch it from winter to summer tires and reset tire maintenance but according to the manual sounds like I'm SOL

Automatic Reset of TPMS Sensors
After replacing one or more wheels (but not after replacing a tire), the TPMS sensors are relearned to ensure tire pressure warnings are accurate. TPMS sensors reset automatically within two minutes of driving over 15 mph

and

If your Model Y is equipped with aftermarket tires that differ in size from those printed on the Tire Information Label, it is the driver's responsibility to determine the correct tire pressure. Do not drive on public roads when tires are not inflated to the correct pressure.
Warning
Do not depend on TPMS sensors to accurately determine pressures and trigger alerts

I will try to change the wheel size to 20 and then back to 19 to see if it resets anything.. BRB

 

[gt2690b]

Yeah well 18" wheel is not an option.. I did switch it from winter to summer tires and reset tire maintenance but according to the manual sounds like I'm SOL

Automatic Reset of TPMS Sensors
After replacing one or more wheels (but not after replacing a tire), the TPMS sensors are relearned to ensure tire pressure warnings are accurate. TPMS sensors reset automatically within two minutes of driving over 15 mph

and

If your Model Y is equipped with aftermarket tires that differ in size from those printed on the Tire Information Label, it is the driver's responsibility to determine the correct tire pressure. Do not drive on public roads when tires are not inflated to the correct pressure.
Warning
Do not depend on TPMS sensors to accurately determine pressures and trigger alerts

I will try to change the wheel size to 20 and then back to 19 to see if it resets anything.. BRB

Didn't do anything

 

[Goobers]

I have a feeling that tire calculator isn’t properly setup, or at least has the right inputs.

Seems a bit much for it to say you need only 36 psi when going from 255/45/19 to 235/55/18. Especially when others, including myself, having been making even bigger changes, going from 21” to 19” and such without being told we could lower the PSI. Or conversely, seeing even higher PSI on factory 21” if you use 19” as the starting point to adjust.

Since the Model 3 uses 18”, what is the PSI recommendation there? Edit: quick check shows it’s the same 42 for M3.

I would play it safe and just stick to the 42 PSI Tesla has recommended, even for the 18” tires.

 

[MattM24]

i am always getting a low tire pressure warning but i have aftermarket 18s so i do not need to run 42 psi according to tire psi calculator:

OEM Size (255/45R19 SL) Load Capacity: 1764 lbs. @ 42 psi.

New Size (235/55R18 SL) Load Capacity: 1764 lbs. @ 36 psi.

so is there a way to tell model Y to chill on the low tire pressure?? i want to be warned at like 32 psi or something (not 38ish like now)

Did you buy SL tires or XL tires? The factory tires are XL 104. If you have 235/55R18 XL tires, they are also 104.

You still need 42 psi for that to match the 42psi in the factory tires.

Is the an AWD or RWD Model Y?

 

[fiehlsport]

Whether you run 19, 20, or 21" on the Y, it's still going to look for 42psi. There's no way to change the threshold.

 

[gt2690b]

Did you buy SL tires or XL tires? The factory tires are XL 104. If you have 235/55R18 XL tires, they are also 104.

You still need 42 psi for that to match the 42psi in the factory tires.

Is the an AWD or RWD Model Y?

you are right the 235/55/18 104s say 42psi on www.tirecalculator.com (i originally put in the SL ratings)

i also have some 245/55/18 103V which apparently are only good for 1929lbs vs the factory vs 1984lbs of OEM (@ 36 psi... the sidewall says max psi of 51 psi though) ---- any suggestion on what to do with those?

*confused a little still*

Edit: apparently SL is pretty much always 36 psi and XL is 42 psi..

 

[MattM24]

you are right the 235/55/18 104s say 42psi on www.tirecalculator.com (i originally put in the SL ratings)

i also have some 245/55/18 103V which apparently are only good for 1929lbs vs the factory vs 1984lbs of OEM (@ 36 psi... the sidewall says max psi of 51 psi though) ---- any suggestion on what to do with those?

*confused a little still*

Edit: apparently SL is pretty much always 36 psi and XL is 42 psi..

SL tires don’t change their load rating above 36 psi (or 35 psi on p-metric tires).

I have always wondered about running SL tires with the same load rating as XL tires, but don’t have any experience on the issue.

 

[455dan]

i am always getting a low tire pressure warning but i have aftermarket 18s so i do not need to run 42 psi according to tire psi calculator:

OEM Size (255/45R19 SL) Load Capacity: 1764 lbs. @ 42 psi.

New Size (235/55R18 SL) Load Capacity: 1764 lbs. @ 36 psi.

so is there a way to tell model Y to chill on the low tire pressure?? i want to be warned at like 32 psi or something (not 38ish like now)

Why not just run at 38-39 PSI and be done with it. I am running similar to your set up, right now 235/55-18 front and 255/55-18 rear tires
On a cold morning they are at 38-39 PSI and when warm 40-41.
Never gotten a low pressure alert.
Getting some better watt hour numbers than the 21's, improved ride, as well as better on center feel and they are quieter. I will be watching the wear patterns as well. The tires I bought are rated to 51 PSI.

Are you wanting to run the lower pressure to further soften the ride?

 

[gt2690b]

Why not just run at 38-39 PSI and be done with it. I am running similar to your set up, right now 235/55-18 front and 255/55-18 rear tires
On a cold morning they are at 38-39 PSI and when warm 40-41.
Never gotten a low pressure alert.
Getting some better watt hour numbers than the 21's, improved ride, as well as better on center feel and they are quieter. I will be watching the wear patterns as well. The tires I bought are rated to 51 PSI.

Are you wanting to run the lower pressure to further soften the ride?

no it went away... its like 37 on cold mornings and 39ish so far when warm (not hot yet).. so yeah i'm happy it just took longer than i would have figured for the warning to go away apparently its 33ish PSI is when the warning comes in

 

[Skavatar]

good to hear it went away. i'm running 38 psi cold on the stock Gemini Pirelli Scorpion MS. wear is very even across the entire tread on all four tires.