Adjust TPMS range

[Victorofhavoc]

Does anyone know how to adjust the tpms sensor range for the correct pressure for the tire?

I just put on my winter set in a 255/40/18 and set my pressure to the correct 29/27 psi for the load rating, but I cannot figure out how to reset it for the life of me! It keeps telling me that 27 is too low, which is wrong for this size tire and load. I've looked through every menu I can think of to find it, and nothing references tire pressures.

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[creaturemachine]

Congrats, you might be one of the few people (on this continent at least) who's done their homework and adjusts pressures for load. I wonder if this is why rotation sensing systems are gaining in popularity over tire sensors, since these can be shipped in markets where they expect people to know how to maintain a vehicle.

 

[Victorofhavoc]

Congrats, you might be one of the few people (on this continent at least) who's done their homework and adjusts pressures for load. I wonder if this is why rotation sensing systems are gaining in popularity over tire sensors, since these can be shipped in markets where they expect people to know how to maintain a vehicle.

Comfort, safety, and proper wear man.

Is there no way to adjust the tpms range?

The other benefit of wheel speed sensor method is cost and reliability.

 

[StingertimeNC]

ECU tuner can probably do it. I can't imagine that's a stock feature. Seems way too advanced.

 

[Victorofhavoc]

ECU tuner can probably do it. I can't imagine that's a stock feature. Seems way too advanced.

So I get no windshield washer fluid sensor, no memory seats, no ability to adjust tire pressure sensor appropriately, and I can't adjust the parking sensor volume?

Killin me

 

[StingertimeNC]

lol. I know. But let’s focus on what you do get instead.
Lots of driving fun.

 

[Victorofhavoc]

lol. I know. But let’s focus on what you do get instead.
Lots of driving fun.

It's definitely fun to drive

It's just a Bosch ecu, I wonder how difficult it would be to have a similar thing to obd eleven, but for acura/Honda. They've forayed away from the VAG platform recently, so maybe there's potential. That would allow for a lot of retrofit and fun stuff, like changing the one tap turn indicator from 3 blinks to 4.

 

[ChromaPop]

I am confused how 27 PSI is the right tire pressure under any situation for this car?

 

[Victorofhavoc]

I am confused how 27 PSI is the right tire pressure under any situation for this car?

A 255/40/18 has a much higher sidewall load rating (read stiffer sidewall) than the factory 265/30/19. 27psi in the former supports the same weight as 33psi in the latter.

You can either look up and printout a "tire load index xl chart" where you match your tires load index (factory is 93) weight to the weight for the new index (99 in my size) and that will tell you the new psi to support that weight.

Or you can go applet route and use this site: https://tiresize.com/pressure-calculator/

 

[norsairius]

A 255/40/18 has a much higher sidewall load rating (read stiffer sidewall) than the factory 265/30/19. 27psi in the former supports the same weight as 33psi in the latter.

You can either look up and printout a "tire load index xl chart" where you match your tires load index (factory is 93) weight to the weight for the new index (99 in my size) and that will tell you the new psi to support that weight.

Or you can go applet route and use this site: https://tiresize.com/pressure-calculator/

Wow, I didn't know about this. Thanks for sharing the link!

Looks like moving to my winter set (235/40/18, XL load) means a drop of 2 PSI vs. what's on the door jamb would be appropriate. I'm curious to see how much of a difference this makes in terms of driving feel and handling.

 

[ChromaPop]

A 255/40/18 has a much higher sidewall load rating (read stiffer sidewall) than the factory 265/30/19. 27psi in the former supports the same weight as 33psi in the latter.

You can either look up and printout a "tire load index xl chart" where you match your tires load index (factory is 93) weight to the weight for the new index (99 in my size) and that will tell you the new psi to support that weight.

Or you can go applet route and use this site: https://tiresize.com/pressure-calculator/

Okay that I understand, but that just means the load support is equal in those two situations. I still believe that you are putting too much squish into the tire sidewall at that lower PSI which is probably not good for the rubber long-term. I don't see how a little extra support is a bad thing as long as the treads lay perfectly on the road and give you ideal grip and traction.

 

[Victorofhavoc]

Wow, I didn't know about this. Thanks for sharing the link!

Looks like moving to my winter set (235/40/18, XL load) means a drop of 2 PSI vs. what's on the door jamb would be appropriate. I'm curious to see how much of a difference this makes in terms of driving feel and handling.

Taller sidewalls also have more variability in the psi change, so a 2psi change down on a 235/40 would lead to 60lbs less load per tire. That's 3.75% of rear axle gvwr. This is super relevant in more fine tuned situations like towing or racing. Race car builders will typically shove the smallest wheel they can fit over their brakes to fit the most sidewall in, which allows them to have more variability in tire pressure to tune for each track and surface.

 

[Victorofhavoc]

Okay that I understand, but that just means the load support is equal in those two situations. I still believe that you are putting too much squish into the tire sidewall at that lower PSI which is probably not good for the rubber long-term. I don't see how a little extra support is a bad thing as long as the treads lay perfectly on the road and give you ideal grip and traction.

The sidewall cares about load support and that's it. There's no negative effect from a lower psi and it won't "squish" more than the same load would on the factory sizing.

Overairing the tire would actually cause faster center wear, stiffer ride, more vibration, weaker braking and acceleration.

If I were to run oem pressure, the tire load would be supporting 200lbs more per tire. That's 800lbs more sidewall load for the vehicle, and a pretty far cry from stock for daily driving. You're talking 25% more sidewall support than the weight of the vehicle.

Edit: this all being said, when there's a few inches of snow and ice out I will air up by a few psi to round out the tire and provide more center grip... So there's definitely variation for the conditions. The oem spec is just a starting point that applies to most conditions on the road.

 

[Mr. LargeCoffee]

Didn’t know this. Just put my snow tires on yesterday and ran the numbers, should put an extra psi in the snows. I actually put in 2 psi figuring that the temperature is going to drop anyway.

 

[ChromaPop]

The sidewall cares about load support and that's it. There's no negative effect from a lower psi and it won't "squish" more than the same load would on the factory sizing.

Overairing the tire would actually cause faster center wear, stiffer ride, more vibration, weaker braking and acceleration.

If I were to run oem pressure, the tire load would be supporting 200lbs more per tire. That's 800lbs more sidewall load for the vehicle, and a pretty far cry from stock for daily driving. You're talking 25% more sidewall support than the weight of the vehicle.

Edit: this all being said, when there's a few inches of snow and ice out I will air up by a few psi to round out the tire and provide more center grip... So there's definitely variation for the conditions. The oem spec is just a starting point that applies to most conditions on the road.

Excellent explanation!

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