German Car Zone

I know several ppl who have actually put non RFT's once their tyres wore out because they werent happy with the comfort and noise. They actually put normal tyres on and shoved a spare in the boot.

I am happen to be one of those, and the sad thing is that you lose boot space in doing so.

You haven't research runflat tyres very well at all... They are designed to be driven on when you get a puncture so if you blow a tire on christmas eve you can still drive until you can get it replaced... for like 500km i think at a max of 80kmh

Great thread.

No one I know with a BMW and runflats likes them. They're noise and seem to ride hard even on smooth pavement. I'd never have them on anything. I've had 1 flat in the last 5 years so to me they aren't worth the trouble.

M

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^ Run flats, even the Michelin PAX solution witch sacrifices driving dynamics the least, still have a long way to go. Then there's the infrastructure/service for repairs.

A Formula 1 run-flats tire war (in slicks form) would have done miracles for the progress/development of this technology; new compounds, new manufacturing techniques, weight reduction, roll reduction, degradation reduction and so forth. But then again, Mosley's a idiot, and without stiff cut-throat competition and incetives, the manufacturers just won't bother (that) much.


Now onto BMW, I agree about the oversizing and runflats, but the rest is kinda B*.
The M cars are not, nor should be prestige cars. There's plenty of those around. They should remain driver's cars, and shave those luxury items and the weight they add, and use more weightsaving alloys and composites.
If BMW wan't AWD and turbos they should created a new sub-brand, and not use the M moniker.

I have them on my car and i do not mind them. Although i admit they're noisy i have no bad experience with them. But, but... My new car will have spare tire and i won't take them again.

It's better for sure with normal tires.

I agree that runflats should be provided as an option for those who want the extra safety/security. Putting them as standard particularly on M-sport equipped cars in markets with bumpy road conditions is a mistake IMO. The space-saver spare, with the tools to use it, is the best solution. For me.

That being said, I can definitely understand how most consumers would feel more comfortable driving to a safe spot rather than, say, having to stop at the side of the road on a cold, rainy night on a shoulder barely wide enough for a motorcycle to stop safely, with cars and big rigs whizzing by at 50-80 mph. Now imagine that scenario, but with your family in the car. Or standing outside.
This is a benefit that consumers realize everyday, and has even been documented in various roadtests. For example:
Dueling Coupes: 2008 BMW 335i vs 2008 Infiniti G37S - New Car, Truck, and SUV Road Tests and Reviews - Flat Tire - Automobile Magazine
Also, the reason why you don't see the GT3 on Evo's COTY 2006 issue, even though it was a finalist, is because it got a flat tire. In the issue's preface, the editor gave insight into the ridiculous process of getting it fixed and summed up:
"For us, it meant the GT3 couldn't make the cover shoot; for an owner on holiday, it would wreck the experience."
Granted, the GT3 has bespoke tires in uncommon sizes. However, the Z4 Coupe in the same test clipped a large rock that wrecked the wheel and blew out the tire, yet was able to continue safely onto the next destination.

Another safety benefit to runflats is that they reduce the risk of losing control of the car in the event of a blowout. These may be extreme examples, but they illustrate the point:
"I witnessed a Z06 driver cross a stinger at near 150mph, puncturing all four wheels, but managing to keep the car tidily under control."
Corvette Z06 (2006-) | Features | 4car | channel4.com

BMW M5 Touring Crashes From Flat Tire At 180 Km/h - 112 Mph

Even when people are expecting a blown tire, they still lose control with conventional tires:
Flat but not out - Telegraph

I am afraid that is a bit misleading, and there is a difference between having a puncture and a blown tyre. A puncture case results in a gradual loss in tyre pressure whereas the blown case is almost instantaneous loss and it is catastrophic to life of the tyre.
RFT have a solid member, in the case of the ones used by BMW a solid side-wall that is designed to support part of the load of the car, as you lose tyre pressure more of the load is transferred to the side-wall. At a certain pressure (varies with the weight if the vehicle) 100% of the load is supported by the side-wall. When this happens, you can be rest assured to condemn that tyre.

I can't think of any RFT that offers you a 500 km range, the 3 series gives you about 150-200 km range while the X5 gives you about 100 km range(the weight of the vehicle influences the range). The 1 series may give you something better than the 3 series but 500km in my limited opinion is a stretch with existing technology in the market.

• So yes, you can drive on it and maintain decent maneuverability if the scenario is a puncture/slow leak. If you have a spare, you can pull over to a point of safety and change the tyre, and possibly have it fixed- however if you do not have a spare and drive on it till 100% of the load is now borne by the tyre, then I am afraid you have to get a new one. It is worth noting that they are quite expensive.

• No you can't drive on it if it is blown scenario. So if you are driving home on Christmas eve and you blow a RFT tyre, and you don't have a spare- dur fromage.

There's really nothing as refreshing as a good BMW-bashing thread.

BTW, I never liked those RFTs.

I replaced the runflats on my 530i because they were way to harsh for the 19inch M wheels and now the car rides superbly and is very comfortable on my daily commute.... I also have a space saver spare just incase