Z4, getting rid of runflats, do I need to detach the...

[Tony 1234]

runflat sensors, I was told today that I have to, but I don't think that's correct?

Anyone

Tony

[Raify]

BMW runflat sensors work on the rotational speed of the wheel. IIRC, they're connected to the brake caliper and NOT the wheel / tyre or any other stupid place a Quick Fitter employee tells you.

I threw the ruinflats away on the MINI and had to change nothing.

[phelix]

Some BMWs have special tyre valves that transmit the actual pressure to an aerial in each wheel arch and some use the ABS sensors to detect changes in rotational speed. The valves are expensive to replace as some have found out when changing wheels.

[DSM2]

BMW do not use tyre sensors at all on their current range, I don't think. All of their RFT systems work off the ABS system, sensing different rotational speeds.

Indeed, were you to fit non RFT tyres to a BMW designed for them, the system would still work and will tell you if a tyre loses significant pressure.

You are aware that you may well invalidate your insurance if you remove the RFTs aren't you?

Edited by DSM2 on Monday 25th February 22:43

Edited by DSM2 on Monday 25th February 22:57

[< FORZA WEST]

No you dont....The pressure is monitored via the wheel speed sensors.the system will still work as pre normal.

[greygoose]

DSM2 said:

You are aware that you may well invalidate your insurance if you remove the RFTs aren't you?

Edited by DSM2 on Monday 25th February 22:43

Edited by DSM2 on Monday 25th February 22:57

Surely if the tyres fitted to a car are in good condition and have appropriate amounts of tread an insurance company would have difficulty turning down a claim on the basis they weren't run-flats wouldn't they?

Edited by greygoose on Tuesday 26th February 09:00

[DSM2]

RFTs have very stiff sidewalls,that's how they work. According to BMW, and there is some truth in this, the suspension is designed bearing in mind the stiffness of they tyre sidewalls, which are obviously a part of the springing / damping system.

Changing for regular tyres changes the overall effect, (which is why people do it mainly, to improve the ride) but, again according to BMW, the handling, against design spec. is compromised and they will not approve the change.

I believe the 5 series has some variants that can run regular tyres but the 1,3,6,X,and Z are designed to only run on RFTs.

[Tony 1234]

Yes, the insurance question, anyone changed to non runflats and not informed their insurance?

Would not have thought it mattered.

Tony

[Raify]

I didn't bother informing my insurance, since you can order a brand new MINI without ruin-flats.

When a BMW mechanic turned up at my house with a 5-series touring, he had binned them too.

[trackdemon]

Our coupe has been runnung run-flats for a while now, without problem. It drives better too...

[phelix]

Tony 1234 said:

Yes, the insurance question, anyone changed to non runflats and not informed their insurance?

Would not have thought it mattered.

Tony

My 535d came as an AUC with conventional tyres and a space saver spare.

I can't see how run flat vs non run flat could influence a claim; far more important in the condition of the tyres and their inflation pressure.

[KenD]

With run flats, spring /damper settings are different due to stiffer sidewall of the tyre.
So if you change to non run flats it affects the overall handling characteristic.
If you modified the suspension would you tell the insurance company?
With insurance companies insisting it is down to the individual to declare all relevant information. I would not like to take the chance of having a claim turned down. The majority of BMW's come with run flats as standard and non run flats is not an option. So would this make putting non run flats on a modification from standard?
I would always notify the insurance company of a modification in writing.
Ken

[phelix]

But can't you get 19s as a factory on a 5 series, whether SE or sport, and they're conventional tyres? And the suspension is unchanged?

[DSM2]

KenD said:

With run flats, spring /damper settings are different due to stiffer sidewall of the tyre.
So if you change to non run flats it affects the overall handling characteristic.
If you modified the suspension would you tell the insurance company?
With insurance companies insisting it is down to the individual to declare all relevant information. I would not like to take the chance of having a claim turned down. The majority of BMW's come with run flats as standard and non run flats is not an option. So would this make putting non run flats on a modification from standard?
I would always notify the insurance company of a modification in writing.
Ken

Exactly. The insurance companies will clutch at straws to turn down a claim. I would not risk not telling them.

[DSM2]

phelix said:

But can't you get 19s as a factory on a 5 series, whether SE or sport, and they're conventional tyres? And the suspension is unchanged?

As I've already said the 5 series has both RFT and normal tyres amongst its options. The 1,3, Z and other models are only supplied with RFT and BMW will tell you that the suspension is tuned with RFTs in mind on those cars.

[plowy]

Tony 1234 said:

Yes, the insurance question, anyone changed to non runflats and not informed their insurance?

Would not have thought it mattered.

Tony

tony my z4 3.0i is on Falken FK452's and they are awesome on this car, I think it's true to say that BMW talk an absolute load of politically correct tosh on the RFT issue, they can hardly be seen to say that the cars they sell are 'better' on RFT's, a mate of mine works at the local dealer and it's well known in the BMW network that cars are better driving machines on nonRFT but they will not tell a customer that. as for the insurance issue i rang my insurer and was told as long as they are road legal (tread depth) in the event of a claim they weren't bothered RFT/no RFT whatever, it don't really matter i would say in my experience.

[DSM2]

plowy said:

Tony 1234 said:

Yes, the insurance question, anyone changed to non runflats and not informed their insurance?

Would not have thought it mattered.

Tony

tony my z4 3.0i is on Falken FK452's and they are awesome on this car, I think it's true to say that BMW talk an absolute load of politically correct tosh on the RFT issue, they can hardly be seen to say that the cars they sell are 'better' on RFT's, a mate of mine works at the local dealer and it's well known in the BMW network that cars are better driving machines on nonRFT but they will not tell a customer that. as for the insurance issue i rang my insurer and was told as long as they are road legal (tread depth) in the event of a claim they weren't bothered RFT/no RFT whatever, it don't really matter i would say in my experience.

At least you have it on record that you advised them. Having said that I do not believe tread depth is the only criterion an insurer would go on. there are many features about tyre spec that can invalidate insurance including sizes, speed and load ratings.

I have no doubt that it could be safe to change to non RFT, and you oould well improve the handling and will certainly improve the tyre life and ride.

In this day and age though, I would not risk not advisng my insurer first.

BTW what would you do now if you had a flat out on the road?

[plowy]

DSM2 said:

BTW what would you do now if you had a flat out on the road?

have two cans of holts tyre weld in the boot with a Halfrauds 12v compressor..

[DSM2]

Fair enough, though the Tyreweld isn't that effective in my experience.

To be honest, unless you have a catastophic blow out, the odds are the TPMS will tell you you have a deflating tyre before it goes down too far and you should be able to reinflate with the compressor to get you home.

In my experience any injury that tyreweld will seal, would not go down that fast anyway, unless whatever caused the puncture came out, which is unlikely to happen before your TPMS has indicated a loss of pressure.

And at the end of the day, punctures aren't that frequent an occurrence anyway. I am 5K into my third set of tyres (RFT) on my 3 series, the previous sets changed at about 23K each. No punctures at all so they were a good thing to have! Not!

[Raify]

And I saw 3 punctures in less than 8k miles of run flat motoring. Since I changed them I've done 12k miles on the normal tyres with no punctures at all.

Anecdotal evidence, isn't.