What's the story with "Run-Flat" tires?

[autobonrun]

First, I've never seen the use of run-flat tires take off like I thought it would. I assume the price is still prohibitive.

However, while watching an old Nascar race, and seeing a car go into the wall when it's right front went flat, I wonder why they are not used in racing? Would they not help maintain control and reduce accidents?

Are any of you using these type tires for street or track?

[makaio]

I know the new corvettes use them. I think I read somewhere they are a comprimise tire. Where they don't have the performance of a dedicated Super High Performance tire. But I could be wrong.

[emcon5]

NASCAR does use a type of run flat tire, and has since the 60's. It has an inner liner that prevents them from going completely flat. They don't have the cornering grip of an intact properly inflated race tire though. The idea is that you can limp home (or in NASCAR's case back to the pits), rather than keep racing. They are limited to slow speeds and short ranges (Tire Rack says 55mph for 50 miles).

When your 3500lb car is in a 140+ mile per hour turn, and your right front has the largest load, if it goes flat, hang on to your butt, because you are going to hit the wall.

Tom

[Zeke]

Originally posted by autobonrun
First, I've never seen the use of run-flat tires take off like I thought it would. I assume the price is still prohibitive.

However, while watching an old Nascar race, and seeing a car go into the wall when it's right front went flat, I wonder why they are not used in racing? Would they not help maintain control and reduce accidents?

Are any of you using these type tires for street or track?

Well, stock cars do use an inner liner on some tracks. But given that a half pound of air pressure will change the handling characteristics of the car, going down to the inner liner won't help much in the middle of a corner while driving right on the edge. Tire weight is also a factor in racing.

On the other hand, I spoke with a fellow who drove a C5 Vette on four run flats with no air at a track on a GM dealer demonstration day. The car apparently worked so well at averge street speeds it was hard to tell that the tires were airless.