BMW Answers:Does fitting non run flats invalidate my warrant

[petrolhead]

Answer:

Thanks for your email.

Your BMW Z4's suspension and braking components are set up to accommodate run-flat tyres. If you decide to change to non run-flats, it may alter the driving and handling characteristics of your vehicle. It’s not something that we recommend, but you can have standard tyres fitted. You’ll need to buy either a spare wheel with jack and brace set - or a mobility kit though. These can be ordered from your nearest BMW Approved Centre. Converting a vehicle from run-flat tyres to conventional tyres will not invalidate its warranty, although a warranty claim could be rejected where the fitment of conventional tyres is found to be directly linked to the cause of any fault or defect.

Kind regards

Paul

BMW Group

United Kingdom
Paul Dransfield
Customer Information Executive
Customer Information

[metal licker]

[john-e89]

Nice 1 Petrolhead, it's something i've been meaning to ask the dealers.

[Denis O]

Answer:

Thanks for your email.

Your BMW Z4's suspension and braking components are set up to accommodate run-flat tyres.
Kind regards

Paul

BMW Group

United Kingdom
Paul Dransfield
Customer Information Executive
Customer Information

I'd love to know how he would explain the differences in set up in comparison to non run flat tyres. His inference is they are somehow, magically different.

The main difference between going from RF's to non RF's is the suspension improved beyond all recognition. The brakes didn't change FFS.

[techathy]

I'd love to know how he would explain the differences in set up in comparison to non run flat tyres. His inference is they are somehow, magically different.

The main difference between going from RF's to non RF's is the suspension improved beyond all recognition. The brakes didn't change FFS.

Basically the spring weight is lighter & damping rate is slower, aka softer suspension, to accommodate the need for the suspension to absorb more noise, vibration & harshness from the road.

[Denis O]

I'd love to know how he would explain the differences in set up in comparison to non run flat tyres. His inference is they are somehow, magically different.

The main difference between going from RF's to non RF's is the suspension improved beyond all recognition. The brakes didn't change FFS.

Basically the spring weight is lighter & damping rate is slower, aka softer suspension, to accommodate the need for the suspension to absorb more noise, vibration & harshness from the road.

Thanks for that. Probably explains why springs are always breaking. They're made of cheese.

Any comment on the braking aspect of things.

[techathy]

Spring cracking is a quality thing. The weight of the spring doesn't have anything to do with how well they're made. But running on RFT tyres will ramp up the fatigue rate of the spring.

Brake, ABS may need to be a more sensitive to lockup situations as there's a higher risk of tyre skip over the road surface.