dizwiz24

I just wanted to make a point here. I used to be an engineer at Goodyear. While I did not specifically design Corvette C5 tires, I have seen a lot of their test data on C5 tires.

This might surprise you, but there is no difference in traction between a Goodyear run-flat Eagle F1 and a non run-flat Goodyear Eagle F1. This was in a test with the same tread compounds, construction, size, etc. Maybe there are other brands out there that are better, but run-flat vs. non run-flat I saw no difference in the dry or wet trailer traction braking test....To my surprise.

I keep seeing these comments like, "I replaced my run-flats with non run-flats, and it rides so much better" Thats like posting, 'I looked out to the east and noticed the sun rises every morning' GM designed your cars suspension softer to account for the added stiffness of the runflat tires inserts. By going to any other non-run flat tire (except maybe the BFG g-force series which has its own insert for cornering stiffness), you have effectively softened your suspension. I cant imagine you get as good, darty steering response with non run-flat tires (unless they have cornering inserts like the BFG's).

While future C6 run-flat tires will be better riding (softer, thinner inserts), be advised, with all the complaints about ride, they wont have the up-to-a 200 mile range in run-flat conditions. I have even seen NLECTEC (some national law enforcement agency) data indicating that some run-flats were able to hold up for miles after being deflated with police stop sticks. Although the tires in the NLECTEC report werent the C5 tires, its thought that they, with their lowprofile, would be able to stand up to the stop sticks as well/better. It just surprises me that, given these tires extreme durability everyone is out to replace them.

If you're not a Goodyear fan, Bridgestone makes a better traction (they dont have to worry about meeting O.E.'s rolling resistance requirements so they can put a stickier, hotter, compound on it) run-flat Firestone SZ50 (made in Japan with the Firestone name on it) specifically as Corvette C5 replacement tires.

In the tire industry, dry trailer traction braking is used to determine the peak and slide values of friction attained. This is what determines a tires 'traction'. In wet traction if mu (friction) is over a certain value, it gets an 'A' rating, 'AA' rating if the wet trailer mu is over a higher level of friction yet, etc.

Any thoughts?

johnnyvettes

whatt ever , i love my pilot sports you can have those runcraps ! if they handel as good as goodyear non runflats then you can keep those to ! J.M.H.O! :skep:

LoneStarFRC

dizwiz24:
Did the data you saw include any figures on the Eagle F1 GS-D3?
Robert



[Modified by LoneStarFRC, 6:32 PM 6/17/2003]

Mean Green

they are....and thanks for the input :skep:

JCL

DizWiz. Interesting......... I'm contemplating the Firestone SZ-50 like you were talking about. Too many choices though.......JCL :yesnod:

C5 StockSwap

:skep: :skep:

J-Rod

My question would be, if they were superior, why did GM switch to a non-runflat on the Z06...

pewterhdtop

I do a lot of open track events, and I picked up nearly 5 seconds a lap going from the run flats to S03s. They handle and stick so much better than the Good years!! Plus, the S03s are less expensive, and I get longer tire life out of them!

When a run flat comes out that matches the performance of the S03s for the price, I may consider going to them, I do like the idea of a run flat tire for safety on the road. :auto:

EuG

Screw “soft ride” I don’t care about that – it’s a Vette after all.
All I know is when I put G-Force KDs I must’ve added another 0.1G to my cars cornering abilities. :eek: :D

Handling is where all the difference is. :thumbs:
Plus run-craps are much heavier too.

SDVette

Interesting post, but I think you need to get out of the lab and ride in some C5s with the different tires on them.

At 20K miles and 6/32 left, my stock runflats were so punishing that I was avoiding driving my car. Every minor road imperfection (lane dots, minor bumps, joints, cracks, etc) would rattle the car so hard I would cringe. It literally took the fun out of driving the car - not to mention the danger of the bump steer it can cause.

I find the F45 suspension in 'performance' mode, and the addition of the Z06 stabilizer bars a fine combination with the non-run-flat Kumho MX tires. And they also grip better.

Let's not turn this into another pissing contest about tire choice. I think we all can agree that the runflats provide added safety at the cost of ride quality. Every individual has a different tolerance for trading these off.




[Modified by SDVette, 5:18 PM 6/17/2003]

geekracer

Since you asked :cheers: I would like to know if there continues to be no difference as the tire wears down. I'm on my second set of runflats and can see IMHO that they aren't as 'sticky' when they get more that halfway worn down. I'm now considering replacing them with something else myself.

Also you might consider that people switching to different brands are going to be comparing their worn out runflat tires to whatever new tire they bought. Of course there would be a difference. :thumbs:

Wicked C5

Sorry sometimes data on paper isn't real world. Run flats are crap I've had several set's of each and would never go back to a run flat.

AC54ME

:iagree: :thumbs: :iagree:

C5Coupe

The non-runflats are lighter tires which translates to better performance.

robsvette

:withstupid: :withstupid: :withstupid:

robsvette

runflats worn halfway down absolutely gave me no traction. brand new they gave me somewhat better traction but not nearly a fraction of the awesome traction i get out of my BF kds. less ride noise and smoother ride to add. its nice all the lab tests you saw and that your're an engineer but experience from all of us forum members with non-runflats beats all that. now you have to buy a c5 and try this out for yourself so you can see. :cheers:

MiamiDave

RF vs. NRF New vs. Old. Let's say tire size, compound, and age being equal (same company), the difference between the two is minor.

As the miles wear on, the GYRF's vs. everyone else's NRF seem to be harder riding, have less traction, and are a lot noisier.

Want a real test? Get someone with GYRF's with 1,000 miles on them and have thewm roar around the track for an hour, than slap on similiar GY NRF's with a 1,000 miles on them (same born on date and storage).

Than, test the two other similar sets with 10K worth of mileage. Guess where my money's goin (check sig if 'ya doubt :thumbs: )

LS7

:leaving:

LittRedCorvette

Sorry, you'll have to dismount my pilots off my cold wheels, over my cold dead body, before I switch back to RF's....... :seeya

LoneStarFRC

:lurk: :lurk: