Aftermarket wheels and runflat sensors

[stuart-b]

I am swapping the wheels on my car to non OE wheels - how does this work with the run flat sensors?

Many thanks

Stuart

[Vladimir]

stuart-b said:

I am swapping the wheels on my car to non OE wheels - how does this work with the run flat sensors?

Many thanks

Stuart

They are actually sensors in the ABS system that measures wheel speed. If one changes, the pinger goes off.

Different wheels make no difference.

Very few cars have proper pressure monitors.

[stuart-b]

Vladimir said:

They are actually sensors in the ABS system that measures wheel speed. If one changes, the pinger goes off.

Different wheels make no difference.

Very few cars have proper pressure monitors.

Thanks for that - one of mine is going off and I can't reset it. The wheels are OK and the pressures are not lower. What could the problem be? Faulty sensor?

[LocoBlade]

When you say you can't reset it it, what do you mean? There's an option in the on board computer to reset the system whilst you're driving, if its like my 1 Series you just need to scroll through until you see (I think) a tyre with an exclamation mark next to it, then click to reset.

[Vladimir]

If what Loco says doesn't work, it could be faulty. Reset it any time you change tyre pressures, stick new tyres on, etc. In my auto BM, you need to have the engine on but be in P mode.

[stuart-b]

Thanks, small update to this. The warning continued, and continued - and I would check the pressures every day... OK. Then I thought, why not pump up the tyres to the max setting for 4 people - and low and behold, the sensors cleared. Then I simply reduced it by 10%, and now everything is fine.

[jonno_]

On the abs-based system, it measures differential rotational speed, since that's what indicates a flat - i.e. relative circumference.

I'd keep checking them, odds on you've still got a problem. Flat, dodgy valve or alloy crack.

[Doink]

As above, the abs sensors sensed one of the circumferences was different so it pinged up the fault, technically you can pump the tyres up to 100psi and so long as you reset the system in idrive the system will assume 100psi is normal and any deviation from that it'll ping up, everytime you alter the pressures reset it in idrive, the computer needs to know a saved circumference in order to be able to detect another measurement

[stuart-b]

Doink said:

As above, the abs sensors sensed one of the circumferences was different so it pinged up the fault, technically you can pump the tyres up to 100psi and so long as you reset the system in idrive the system will assume 100psi is normal and any deviation from that it'll ping up, everytime you alter the pressures reset it in idrive, the computer needs to know a saved circumference in order to be able to detect another measurement

Agreed, but I think that in my instance the computer wasn't resetting properly. Since I've pumped it up, and reduced it back again, no ping. It has been 4 weeks since I did that and nothing since. In my book, cured

[LocoBlade]

If its anything like the 1 Series, you have to press and hold and wait for a tick on screen. Its quite easy to press the button thinking you've selected it but it just clears the screen without doing anything.