Tire Pressure with Style 219s?

[spnsprt]

Hey Folks,

This might be a dumb question but when you don't have stock wheels do you still keep the stock tire pressures? I haven't driven the car in about 2 months and my TPM light came on so I realized I need to figure this out. Right now I've got Style 219s on with RS4s that are 235-40-18 on the front and 255-35-18 on the rear.

Also, I've seen info all over the place on what the right tire pressure for our cars is. What do you all run?

[Tbonem3]

It can vary for different factors. I would search forums for feedback on what RS4 like for a given climate.

If you're not having any luck, I can't imagine you'd have any issues with using something like 33F 35R (cold).

You may already know ofc, but FYI, the rear tire is too small. Should be 265/35/18 or 255/40/18.

[mrgizmo04]

Tmp turns on when rolling circumference on an axle (front or rear) differs left to right, independent of tire size.

So, to get rid of the light, check to make sure both front tires are equal in pressure to each other, then check that both rear tires are equal to each other.

Side note, not sure your suspension, camber, driving preferences, but RS4 are stiff sidewall and like slightly lower cold pressures to keep the contact patch down.

Sent from my SM-G950U using Tapatalk

[S3diment]

Also running 219s but mine rub like crazy. What’s your secret?

[spnsprt]

Tbonem3 Didn't know that about the tire size! These are just what one of the shops I went to recommended! Very good to know.

mrgizmo04 I've got the tire pressure measured at 33 in the front and 35 in the rear. But even when i reset the TPM the light comes back on. Do any of you know if the TPM and DSC interact? I ask because I have a track day scheduled for Oct 11 and I'd rather not pay to have the TPMs replaced right now.

S3diment not sure? They were on the car when I got them. Maybe one of the previous owners rolled the fenders? I didn't have any rub on the dinan/konis and now it's on coilovers and still no rub.

[heinzboehmer]

Do any of you know if the TPM and DSC interact? I ask because I have a track day scheduled for Oct 11 and I'd rather not pay to have the TPMs replaced right now.

The TPMS in our car doesn't rely on pressure sensors inside the wheels like it does on other cars. It instead compares the rolling circumference (how far a tire travels in one revolution) of the wheels on the left side to that of those on the right for each axle (presumably factoring in steering angle). Like mrgizmo04 said, if this value is different between two tires (left to right) on the same axle, then the tpms light turns on.

Have you tried pulling codes? If you're sure that the circumference and pressures are the same from side to side then the issue might be a faulty sensor (maybe wheel speed) or something.

[Obioban]

I wonder if you'll be able to reset the light away with those tire sizes. Might be outside of the adaptation range.

Certainly it is going to make DSC WAAAAY more invasive than it would be otherwise. If you're going on track with it, I suspect you might have to turn DSC off to make the car usable.

[spnsprt]

It's so weird because the car has been on these tires for months with no issue. Also my EML/TPS light just came on (P0121 & P0221) and sent the car into limp mode twice! Luckily I keep the ODB scanner in the trunk and was able to erase the codes to get home.

It doesn't seem to pick up any codes relating to the TPM but maybe I'm looking in the wrong places? Either way, time to order some replacement TPS. Since it threw two codes, could that mean two sensors are faulty?

Hopefully I can get this cleared up before my track day! I don't think I'm ready to go DSC off yet since the nut behind the wheel still needs a lot of tightening!

[heinzboehmer]

It's so weird because the car has been on these tires for months with no issue. Also my EML/TPS light just came on (P0121 & P0221) and sent the car into limp mode twice! Luckily I keep the ODB scanner in the trunk and was able to erase the codes to get home.

It doesn't seem to pick up any codes relating to the TPM but maybe I'm looking in the wrong places? Either way, time to order some replacement TPS. Since it threw two codes, could that mean two sensors are faulty?

Hopefully I can get this cleared up before my track day! I don't think I'm ready to go DSC off yet since the nut behind the wheel still needs a lot of tightening!

You should read codes with INPA (or equivalent). The codes you posted are just generic OBD codes. The BMW software will give you significantly more information and might even have some stored codes that don't show up on a regular OBD scanner.

[Obioban]

It's so weird because the car has been on these tires for months with no issue. Also my EML/TPS light just came on (P0121 & P0221) and sent the car into limp mode twice! Luckily I keep the ODB scanner in the trunk and was able to erase the codes to get home.

It doesn't seem to pick up any codes relating to the TPM but maybe I'm looking in the wrong places? Either way, time to order some replacement TPS. Since it threw two codes, could that mean two sensors are faulty?

Hopefully I can get this cleared up before my track day! I don't think I'm ready to go DSC off yet since the nut behind the wheel still needs a lot of tightening!

There's 3 TPS sensors-- the pedal is one.

[spnsprt]

@heinzboehmer that is good to know. Now I need to figure out how since I've only got the basic ODB scanner

Obioban I've read that the other two fail more often? I figured I might try to change one at a time?

[Obioban]

Just depends how soon your track event is :P