jet190rs

e60 suspension was not designed for rft's.
e90 was the 1st bmw designed for rft's.

marklp

Actually, I think it might have been the E87 (1 series)

vern

I'm glad you posted the information about RFT's and the suspension. I've been saying that since before I purchased my 530i and some people felt it didn't make a difference, I guess because they are so against RFT's nothing will change there mind. IMO BMW isn't BSing anyone.
cheers
vern

BetterMakeWay

Actually who gives a $hit about which model was designed for rfs?! Really now, imo we have to take into consideration 2 things: tire feedback, and suspension feedback which are 2 different things. Take the RF tire for example, because of the stiffer sidewall the overall handling of the car in dry conditions might seem better than a similar car equipped with normal tires, but that's just an impression because the normal tires allow more flex in the tire sidewalls even though the suspenion is the same. Now as various users reported and as i'm confident, if you go with bigger rims (+1 some say even +2") and stick them with normal tires, this combo will become more comfortable than the original smaller rims with run-flats, even though the suspension is the same. Of course if you have a standard suspension and 17 or 18" rims+RF the change to non-rf keeping the same rims will seem a step back in handling. Now imo to have the best compromise between handling and comfort would be to go with M suspension + 18-19" rims with normal tires. The flex in the rubber will be enough to keep a comfy ride, the sidewall will not drop beyond comfort level, and the handling in the twisties will be just right because of the M suspenion (which is the hardest oem) and because of the tire feedback. Want more sport? Then just move the notch higher by going with 20" aka lower tire profile and stiffer ride but even more response in handling department. Want super-hardcore!? Then just go nuts and swap to coil-overs and go 20-21"s.
So in conlusion there has to be a relation-ship between suspension and tires (rf or non-rf). It would be weird if not impossible to have standard suspension and in the same time mount a 21" rim on the car for example! So i call BS what the dealer said and what bmw says about which car was made for what! It's simply called marketing and that's what they do. I would be highly surprised if in fact BMW would really detune the suspension to a more comfortable set-up to cope with the RF extra rigidity for a model that "is made for RFs". It would be stupid imo. That's what i said about the harmony of the suspension/wheels. You can't have and shouldn't have smth very tough and rigid as the RF tires and in the same time have a very soft suspenion. That would totally mess up the overall ballance of the car. That's what i think anyway!

Raighne

I have the Bridgestone Potenzas... they are supposed to be better than the other brands.
I've heard mostly negative things about the Pirellis...
You are supposed to feel lucky if you get the Bridgestones on your E90...

07530d

I agree with that, in the wet it gets worse. I have been frightened too much and have just swapped to an E46 M3 with 6K miles. No chance of skipping round corners npw

PS loved the E60 but too big, prefer manual, needed a new drive (at home) and garage, wife hated it.
Guess I just need to excorsice the final boy racer in me (now 40 years old)

BetterMakeWay

Vern i'm not trying to decide where's the truth, i'm just following logic but please read my above post. Let's just say you are right and bmw really did that. Then that would mean for the sake of extra "safety" (nothing whatever to do with marketing and big $ ), they de-tuned the suspenion to a more comfy level so that the RFs could really work. That's like hiding the problems with RF technology. One thing is for sure, those RFs are way too hard, they have less grip in wet conditions (compared to non-rf) and some wear out way too fast. Everybody knows that when the road conditions are poor like rain or mud a softer suspenion would act in fact slightly better than a stiffer one so now by your logic results that in fact they on purpose tried to minimize the feel of the wooden tires by softening the suspenion. Sorry but i simply can't dig that. Why would they then still offer M packs for the E60 combined with M135 rims w/ RFs then?! Or it's a mass conspiracy and the 'M supension is in fact sport suspenion and sport is in fact standard and standard is well comfort' ?!

Soon i will also change to non-rf so i can really talk out of experience, but i can imagine that in very tight corners the car could feel less sporty but as i said that's just an illusion, that is the extra feed-back the non-rfs offer. Hell this is my 1st car with rfs and i can tell how they work. Unless you drive on 60% profile tires then i hardly can think there will be a realistic decrease in sportiness from the change to non-rfs.

07530d

May be the wrong place to ask this - the E46 M3 I just bought, I forgot to check about Run flats, the drive felt very secure - will it have runflats (standard 18 inch alloys) I collect next week

BetterMakeWay

No problem man, but as far as i know E46 M3s do NOT come with RF tires. In fact no M car has RFs. So unless the owner swaped to RF i don't see why it should have RFs.

Another thing to give some thought. How come E60 is supposed to be made for RFs and the E60 M5 doesn't have them?!

Raighne

When I first heard about the concept of run-flats I was very excited and positive about it.
The added safety, security and convenience seemed like such a great development in car design.
I still think that the concept is a great one BUT ... the trade-off in ride quality and in some cases handling just isn't one I'm happy to accept.

Either the technology hasn't been perfected yet and we are just suffering the pain typical of early adaptors OR the technology is fundamentally flawed and will never work. I don't know how it will pan out in the next few years. I would prefer to see run flats improved to a point that they are as good as (or better than) normal tyres. I want to have them...

In the meanwhile though, I just want BMW to give me a choice when I order the car from the factory.
If some customers want a car with normal tyres they should be allowed to order one (with whatever suspension settings are compatible with that setup). If some customers want the RF setup and can live with the trade-offs, they should be able to order that (again with whatever suspension tuning needs to be done to that configuration).