H20Vette

I've seen threads on here where the runflats are referred to as "runcraps" and claimed to negatively affect handling/traction. I've also had people in the tire buisness tell me that the runflats have stiffer sidewalls than non-runflat tires and they they handle better than non-runflats (less sidewall flex/roll).

Ignoring the convenience factor and the price difference of Runflats..... What is the truth? Which type of tire is better for max performance? Runflat or non-Runflat? And why?

Thanks

ljthe2nd

Less flex means poorer traction, it means the tire can't flex, so it looses traction (it stays stiff and the tire slides, when cornering instead of flexing and keeping the footprint of the tire firmly on the ground). As far as off the line traction, I think the compound of the rubber has more to do with traction here. The stock runflats are also noiseier. Were these people in the tire business trying to sell you tires? I took my runflats off at about 5000 miles, I wish now that I'd have taken them off the first day, I went with BF Goodrich, gforce TA kdw tires, I am very happy with them, they are much quieter, handle better and also cheaper than the GY Runcraps.

Avanti

I went from the run-flats to Supercar's. The difference was night and day!

Do it!

All the best.

H20Vette

So the sidewalls can be too stiff? Up to a point a stiff sidewall is good, right? Otherwise the car will "move around" on the tires and roll the sidewalls over in corners. Isn't that accurate?

ghost.rider

You will get max performance from a good set of non run flats since they will not have their design compromised to provide run flat capability.
A well designed non run flat will have just the right amount of sidewall stiffness to maximize cornering grip.

Re "runcraps" usually refers to Goodyears since they can be driven 200 miles without air because of really stiff sidewalls which give a pretty hard ride with a noisey tread pattern.

Michelin Zero Pressures have somewhat softer sidewalls, ride smoother, quieter and are designed to only run 50 miles without air .

C7LOU

I wonder if the run-flats on the new Z06 are a better tire or if people will be looking to dump them as soon as they can for non run-flats.....

ghost.rider

From what I have read, it is a new design and I think it has a shorter mileage limit - maybe 100 miles

vettenuts

Just go to Tirerack.com and look at the user ratings, that will be a very telling tale. The Goodyear D3's come out on top of the heap.

allanlaw

Because of the stiffer sidewall, the turn-in with a runflat may be "crisper" than a non-runflat. However, as your speed through the corner increases (like going 120+ through a sweeper, on the track of course), you get to the point where the "stick" of the non-runflats is what you're looking for, due to the softer compound, sidewall flex, etc. For me, Kumho MX's perform a lot better than the GY EMT's on the track. For tootling around town, who cares.

ljthe2nd

Yes the sidewall must be stiff enough to support the car, but in the case of the stock Goodyear runflats that came on my 04 when I bought it new, the very characteristics that make the tire able to run with no air pressure at up to 55 MPH for up to 200 miles are the the same reasons it has poor traction compared to similar performance tires of the same size (a very stiff sidewall able to withstand these conditions and the added heat build up without being destroyed) unable to flex enough under hard cornering to provide good traction. This extremely hard tire is also much noiseier and gives a rougher ride.

6 speed Sid

Changed to non-run flats and performance did not suffer, as others have said, just have different traits. Overall, I will take the non-run flats for stick in the corners and quiteness.

Mark-44

My non-runflats are now two weeks old.. What a difference in the noise level and now the car has a much softer ride. Traction is much better, especially in hard cornering and on wet surfaces.

Now I do have a "spare tire" issue.

RoadVette1999

I changed from run flats to Michellin Pilot Sports and did not realize the difference, because I had changed out my suspension to a zo6 suspension. Too many changes at once. I then had to revert to my runflats while my rims were being polished. I can't tell you how much difference there is. It is much quieter, and the ride is very smooth. I suggest purchasing another set of rims and regular tires and keeping your stock rims and runflats as spares. Had it not been for my spare runflats, I would have gone 4 months without my car...long story.

H20Vette

you're saying the michelin pilot sports were much quieter and smoother than the runflats, right? the way you wrote it left room for intrepretation...

ROJO99

Runflats are just a way for GM to ship the car with out a jack/spare or any changing provisions. The idea is a good one, but the stiff walls do compromise performance IMHO. Breaking point for me was one cold December morning I was driving to work and while merging on to the highway my rear end broke loose. My FRC only has TC so the movement in the rear was significant.

I switched to GoodYear F1GSD3's 2 years ago and have not looked back. The tires are quite and stick very well with in reason in a straight line or curves dry or wet conditions. I go to the local 1/4 mile drag strip and picked up almost .3 after I switched from run flats to my D3's.

50th year

Driving on a road trip it would always be in the back of my mind I didn't have a spare.
Ron

H20Vette

Get you a patch kit and air compressor. I patched up a runflat just the other day because I didn't want to drive home (I was over 100 miles from home at the time) with it flat and ruin it. It was very easy to do. Just make sure you carry some needle nose style vice grips in case the nail/screw/etc is hard to get a grip on to pull out. A jack and collapsable lug wrench is a good idea too in case you need to remove the tire to get to it. Forum member C5Fredrick sells a great aluminum jack.

So it's settled... when my runflats run out of tread I'm going with non-runflats. Thanks for the info, guys.

MTurnbo

I'm not sure I follow this line of thinking. If the sidewall flexes going around a corner the outter sidewall will roll under and the inner sidewall will roll up thus moving some of the tires footprint off the pavement. A stiff sidewall is what is needed to keep the footprint in contact with the pavement. On the other hand I agree that the tires rubber compound has everything to do with traction both straight line and cornering.

Dave68

Another thing that contributes to the non-runflats superior ride quality over runflats is the reduction in unsprung weight (about 25 lbs). I am always amazed with the smooth ride/excellent handling my GSD3s provide. An added bonus is their incredible grip on wet surfaces.

H20Vette

I don't place ride quality in very high importance. Handling is my #1 concern. This is a high performance car, so I'll sacrifice ride quality for handling any day.

I see a lot of people posting that their non-runflats are so much better than their {worn out} runflats. Well, the runflats were old and worn out, so that was probablu part of it. What I'd like to know is has anyone gone from non-runflats back to runflats and what their impressions were.