The runflats don't have worse grip, prior to 2008 they had a harsher ride which was fixed with suspension changes in the 2008+ cars.

 

thats awkward. When there's no cars around and in an open area, I purposely push it HARD in the rain with my car to test to DSC and it works wonderfully well. It keeps it going without pushing the end out. What's the weather like there? Cold? Under 45 degrees with factory run flats in the rain will kill you.

 

Did you manage to spin it with the DSC switched on?

I know I 'only' have the 3.0 engine but even that has enough power to spin the car with the DSC off on a wet road, however with the DSC on I don't see how you can manage to spin the car. I think it helps that I have the active steering but either way the electronics should save you.

 

That's the point - when cold and when wet the RFT's do tend to have worse grip. On dry pavement they are generally fine (with good turn in due to the stiff sidewall, but compromised due to much higher unsprung weight) but in the cold and wet they are poor. That's the point the OP is making, and he's absolutely right.

 

In looking at the posts, one point is missing. Sport tires are designed for warmer temps. Its the rubber compound, not sure the main differences between the Conti's and RFTs. I suspect the Conti's suck anyway. PS2s are the best option.

If its cold, I take it easy. That said, the neutral balance of the car should lead to the sliding he mentioined. However, the traction control takes care of this anway, and no problem at 30mph.

The poster drove a 2000 Merc, which probably has a good deal of understeer and good ole Merc plowing. Now the poster drives a real sports sedan and he is puzzled. I say he needs to adjust.

I don't have any issues tooling around in RFTs. The main issue is they are hard and loud.

 

i take it easy even with my snow tires. u never know. It's hard to expect what the car will do when ur on ice.

 

Sorry guys, but its not the RFT. Any performance summer tire, RFT or not, will not work well when its colder out. The rubber compound that grips well in the summer gets hard when its cold. The additives to the rubber that make it grip better in the cold make it grip less in the warm weather.

Also summer only tires tend to be performance tires and the best tires for handling are the ones with the biggest blocks of tread. Big blocks of rubber gives more surface or friction area, so a slick (no tread at all) is the best and the tire gets worse as you add more and more tread cuts or voids. There is no gripping power for the voids in the tread.

The voids in the tread are only there for two reasons; one to channel water or minimize hydroplaning, the other is to grip mud, sand, or snow.

The above rules are the same for RFT or nonRFT tires. RFT adds a stiffer sidewall so that if there is a total loss of air pressure it can still support the weight of the car for a short period of time.

 

RUBBISH.

On my previous car I had Firestone Firehawk SZ50-EPs.

AMAZING tire. I wish them made them in more than just 2 sizes, but they don't. Those tires handled so well in the rain I didn't even have to change my driving style. Literally. Those things could evacuate water better than anything I've ever seen in my life. Plus they had different types of compund as the tire wore, very slick technology.

If you're not familiar with them, look here. I had the 24/45/17's on my last car. Cost me $250 a tire. With Koni's, Eibachs, and those tires, the car handled almost as well as the Bimmer, and was $40k less.


+1 on summer tires not working in the cold. I've tried it. NOT fun.

 

I seem to remember a C&D or R&T tire test in which a RFT compared with its normal counterpart were always considerably worse in the rain, and yet better in the dry. I forget the theory but for the given tire test, RFTs were worse for rain.

For the guy with the mishandling 535 and/or hussain, I'd recommend also having the alignment checked.

 

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