Removing Run Flats to Non RunFlats on Z4? Any issues?

[ceestar]

Hoping for some help, as I've been advised that my tires are barely legal. I'm currently fitted with the factory for this particular model ( Z4 '56 Plate ) Standard Bridgestone Potenza RE050 Run Flats.

I was hoping to switch to either the Goodyear F1 Eagle Asymmetric or the Conti 3's. The problem I have is that the info provided by various sources seem conflicting. I've contacted a couple of BMW dealers, and have been advised that changing from Run Flats to non flats will result in various issues due to the way the vehicle has been built i.e suspension and ECU systems. One dealer advised that this wouldn't be an issue but could effect the BMW warranty and insurance but others have advised that this is only the official line but the ECU will definitely be effected. So I'm basically confused.

I contacted BMW warranty services and they advised that the warranty would not be effected, as they dont cover tyres but other sources say that they would not honour any ECU related issues due to modification of the tyres....

Tyres specs MV2 18" FR 225/40/18 Rear 255/35/18.



Any help would be appreciated.

[Sticks.]

Lots of info here, just do a search http://www.z4-forum.com/forum/

Not heard of the ECU issue and can't think how it might be affected. Have F1 Asymmetrics on my 04 with 18s and can recommend them (same pressures). One thing to watch is the rfts are notoriously difficult to remove, so beware of damage to your rims.

And don't forget to notify your insurance company, who probably won't be interested, but still do.

Edited by Sticks. on Wednesday 2nd December 19:53

Edited by Sticks. on Wednesday 2nd December 19:53

[Steve748]

Using the SEARCHreveals all

[ceestar]

Sorry if this is duplicate of any additional threads - First pots and completely new to this....Thanks for the info.

[scz4]

Do it!! No problems. Just much better ride and grip. It will transform the car, no more tramlining and harsh ride.

[JimexPL]

I've recently gone from Bridgestone Run Flats to F1 assymetrics on my Z4 (225/45/17s).

There is an improvement, but I think 'transforming' is overstating the change if you compare like for like (i.e. new RE050s vs. new F1s rather than worn out RE050s vs. new F1s)

Pros -
Cheaper
Less prone to tramlining
Noticeably better ride quality (still hard though)
Quieter
Much better wet weather grip, particularly in cold weather

Cons -
Softer turn in
Lighter steering (but similar feel) - I always run the car in sport mode now to compensate for this

The suspension may well have been optimised for run flats, but by taking away the need for the suspension and wheels to cope with such stiff side walls the effect on your car could only be benefitial.

Remember to put a can of tyre weld in the boot!

[ceestar]

BMW are saying that I wont be able to fit another tyre around the current wheel and would need to change the wheel? Is this correct or are they just giving me the offical line?

[spandexx]

ceestar said:

BMW are saying that I wont be able to fit another tyre around the current wheel and would need to change the wheel? Is this correct or are they just giving me the offical line?

All bks. They try and force you to stay on the silly expensive £270 per corner tyre (that's what they quoted me). I am currently running Run flats on the front as they have plenty of tread left and non run flats on the back. Grip has improved no end in the wet, and the ride is a little better.

I was told by one large chain tyre garage the rims are run flat only, another large chain that it would invalidate the BMW warranty and another that changing tyres like I have is dangerous and made out the car would all but spontaneously combust.

I then found someone who was human and did not just want to flog me crappy hyper expensive run flats, he admitted they are a ste idea and slapped on the tyres I wanted in 30 mins (Falcon 452s). I was a little apprehensive mixing the two but matching the tyre to the axle has not had any detrimental effects whatsoever. I still sling the car about like I did on the run flat rocks and find grip has actually improved no end.

BMW are just towing the party line. If I understand correctly Run Flats are standard across their range including Mini's, so will always push for them.

[ceestar]

This is the exact issue I'm having. I spoke to BMW Insured Wareanty services direct and they advised that it shouldn't be a problem. I've also been advised by another tyre garage that it is possible but will have to reset the sensors....

I thnk I'm going for the F1's but just want to ensure that I can simply replace without causing any issues.

[ben]

Ditch the Run Flats..!
I replaced mine with Falkon 452'S and it feels like a new car.
Don't forget to get some good tyre gunk and a compressor

[Farmer]

ceestar said:

This is the exact issue I'm having. I spoke to BMW Insured Wareanty services direct and they advised that it shouldn't be a problem. I've also been advised by another tyre garage that it is possible but will have to reset the sensors....

I thnk I'm going for the F1's but just want to ensure that I can simply replace without causing any issues.

Sensors????? the presure drop is "sensed" by the ABS system which notices the small reduction in rolling circumference (thus increase in speed compared to the other tyres) when the runflats loose pressure . this system would actualy work even better on a non run flat tyre loosing pressure. Can't for the life of me work out why it would affect your ECU, but I can work out that the person who said it is not to be trusted.

Normal tyres will improve the car to varying degrees and the only downside is the gunk can and compressor rattling round in the boot.

[ceestar]

Thanks All - Opinions on the Conti 3's / F1 Eagle Asynmetrics?

Farmer said:

ceestar said:

This is the exact issue I'm having. I spoke to BMW Insured Wareanty services direct and they advised that it shouldn't be a problem. I've also been advised by another tyre garage that it is possible but will have to reset the sensors....

I thnk I'm going for the F1's but just want to ensure that I can simply replace without causing any issues.

Sensors????? the presure drop is "sensed" by the ABS system which notices the small reduction in rolling circumference (thus increase in speed compared to the other tyres) when the runflats loose pressure . this system would actualy work even better on a non run flat tyre loosing pressure. Can't for the life of me work out why it would affect your ECU, but I can work out that the person who said it is not to be trusted.

Normal tyres will improve the car to varying degrees and the only downside is the gunk can and compressor rattling round in the boot.

[Sticks.]

http://ssl.delti.com/cgi-bin/rshop.pl?details=Orde... shows tyre reviews as well as prices.

FWIW I think the US Z4s had tyre pressure sensors rather than ABS-based system.

I've just bought a second set of F1 Asymmetrics.

[ceestar]

Just got a fully fitted quote for £568 4 F1 Eagles Asy! Think thats pretty good and £600 for the Conti's.

[Sticks.]

That's about what I paid for mine.