Tire Change

[F15d_RN]

I looked to see if there is any thread that could answer my concerns but after a couple of hours, I can't seem to find what I am looking for.
So I apologize if this is a repeat...

I switched from summers to winters today.
My summer set-up was a staggered 20" and switched to a square 19".

Prior to the tire shop mounting my winters, the tech checked online to "disable" the air suspension. He didn't mention anything about it after the changeover and I forgot to ask if he did.
Is it even possible or needed to disable the air suspension during changeovers?

Also, after driving about 100meters, a warning came off telling me that my tires are flat while highlighting all 4tires. I knew none of the tires are flat then It gave me an option to reset the sensor which I did and the warning disappeared. Is this expected every time I change tires?

How do I check if the air suspension is working? There is no sensor/warning that it's not working after the tire changeover.

Thanks for your help guys.

[DuSh]

Originally Posted by F15d_RN

I looked to see if there is any thread that could answer my concerns but after a couple of hours, I can't seem to find what I am looking for.
So I apologize if this is a repeat...

I switched from summers to winters today.
My summer set-up was a staggered 20" and switched to a square 19".

Prior to the tire shop mounting my winters, the tech checked online to "disable" the air suspension. He didn't mention anything about it after the changeover and I forgot to ask if he did.
Is it even possible or needed to disable the air suspension during changeovers?

Also, after driving about 100meters, a warning came off telling me that my tires are flat while highlighting all 4tires. I knew none of the tires are flat then It gave me an option to reset the sensor which I did and the warning disappeared. Is this expected every time I change tires?

How do I check if the air suspension is working? There is no sensor/warning that it's not working after the tire changeover.

Thanks for your help guys.

Yes, that sensor warning is normal - that is your car learning new serial numbers from new tpms set in your winter set. Every changeover you can reset it in menu and car will learn new tpms.

So for air suspension - there is no need to disable anything during simple tire changeover in BMW. Air suspension is perfectly fine and car can be raised without disabling anything and it will readjust itself after car will be lowered down again. Your air suspension is working rest assured - if it was not you would have felt it right away - ride would be teeth shuddering and your car would be slammed like this:

[F15d_RN]

Thanks Dush!
Much appreciated.

[redline9001]

Did you get this sorted out? I know Canadian M cars don’t have tpms I am not sure if other models have them or not as I don’t touch a thing when I swap from summers to winters, just change wheels and drive , no resetting or anything.

[DuSh]

Originally Posted by redline9001

Did you get this sorted out? I know Canadian M cars don’t have tpms I am not sure if other models have them or not as I don’t touch a thing when I swap from summers to winters, just change wheels and drive , no resetting or anything.

Canadian duders have ABS module counting revs of each tire instead of tpms and thus approximating which tire has gone low. It's more or less exact up to the point - definitely less to worry about when changing tires, but not as helpful as having direct readings of tpms too.

[sj22]

Originally Posted by F15d_RN

Prior to the tire shop mounting my winters, the tech checked online to "disable" the air suspension. He didn't mention anything about it after the changeover and I forgot to ask if he did.
Is it even possible or needed to disable the air suspension during changeovers?

Also, after driving about 100meters, a warning came off telling me that my tires are flat while highlighting all 4tires. I knew none of the tires are flat then It gave me an option to reset the sensor which I did and the warning disappeared. Is this expected every time I change tires?

How do I check if the air suspension is working? There is no sensor/warning that it's not working after the tire changeover.

Thanks for your help guys.

Air suspension cannot be manually/easily disabled in my experience. Once or twice in last few years, the air suspension has gotten disabled during a tire change. You will obviously know because the car will drop down on that side a few inches. As soon as you power on the car, the suspension will reset its height.

The RDC system keeps a measure of the rotational distance of the tire w/o having the exact pressure value. The idea is that inflated tires should rotate a fixed distance and if you are loosing air, the distance covered by each rotation will change. I have never had to reset this in my X5 when changing from winter to summer, but once needed it to be reset in my 7-series few years ago.

[wifesbimmer]

Hey, Redline. It looks like you and I share quite the same pallets for cars. I too own an E92 M3, X5, and a truck.

[Qsilver7]

Originally Posted by redline9001

Did you get this sorted out? I know Canadian M cars don’t have tpms I am not sure if other models have them or not as I don’t touch a thing when I swap from summers to winters, just change wheels and drive , no resetting or anything.

Ditto this...some BMWs have TPMS (tire pressure monitor system)...also referred to as RDC and some have FTM (flat tire monitor)...reffered to as RPA.

If you don't have TPMS (actual sensors inside each wheel that sends data to a control module)...then you probably have FTM that as stated...uses tire rotation to determine if a tire has lost air. If you have FTM, you still need to reset the system ANY time that you adjust tire air pressure or change tires etc.

TPMS (aka RDC system)

1 = Wheel electronics system, front left
2 = Wheel electronics system, front right
3 = Wheel electronics system, rear right
4 = Wheel electronics system, rear left
5 = RDC control unit

• 1 = Wheel electronics

FTM (aka RPA system)

Initialising Run Flat Indicator (RPA)
Note:

Checking the tyre pressure is based on speed monitoring of the wheels in relation to each other. A tyre puncture is detected and signalled by way of a deviation in specific speed ratios.

The four tyres mounted on the vehicle are monitored while the vehicle is driving.

Initialisation must be carried out in each case immediately after tyre pressures have been corrected, after tyres/wheels have been exchanged and after repair work to the air spring system.

Attention!

The Flat Tyre Monitor (RPA) is not operational when driving with a compact spare wheel.

Introduction

The Run Flat Indicator (RPA) monitors the tyre pressure throughout the journey.

The entire vehicle weight is carried by the air pressure in the tyres. If the pressure in one of the tyres should drop, the tyre will gradually ”cave in”. The resulting flexing means that the defective tyre will quickly receive additional damage. The tyre could burst.

As tyre pressure drops, the radius of the wheel and with it the tyre's rolling circumference will also decrease. The upshot is that the wheel speed of the affected tyre is increased.
The RPA records the wheel speeds using the wheel-speed sensors of the Dynamic Stability Control (DSC). The RPA compares the speeds of the individual wheels and computes an average speed. In this way the RPA is able to detect a loss of tyre pressure.

The RPA detects a drop in pressure below about 30 % ± 10 % of the initial value. The RPA indicator and warning light indicates a drop in tyre pressure. The RPA will indicate this after just a short distance, as a rule after a few minutes, from a certain minimum speed (e.g. 25 km/h) up to the permissible top speed.

Brief description of components

The SMG system comprises the following key components:

4 wheel-speed sensors

The wheel-speed sensors of the Dynamic Stability Control (DSC) measure the wheel speeds of the individual wheels.