Why Run Flat Tires ??
12-14-2004, 08:47 PM
#21
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Look at the size of the rear wheel/tire and figure out how much cargo space you would lose if you had to design a place to put a spare with accomodation for a flat rear tire.
Even though runflats weigh a bit more than conventional tires, the lack of a spare, jack, and lugwrench saves a good 50-60 pounds, which yields a net reduction in overall curb weight.
In over 40 years of driving I have NEVER had to change a tire on the road. I've had my share of glass and screws in tires, but I was always able to add air until it was convenient to remove the tire for repair.
The 50 miles at 55 MPH is probably on the conservative side. If you're on the road, stop at the nearest place and have a quicky plug installed. When you get back to home base have your tire guy install a "speed rated" patch/plug, which will require removing the tire from the wheel.
Not sure about Corvette guys, but I bet that over 50 percent of drivers on the road today would NEVER attempt to change a flat tire. They'll call AAA.
Duke
Even though runflats weigh a bit more than conventional tires, the lack of a spare, jack, and lugwrench saves a good 50-60 pounds, which yields a net reduction in overall curb weight.
In over 40 years of driving I have NEVER had to change a tire on the road. I've had my share of glass and screws in tires, but I was always able to add air until it was convenient to remove the tire for repair.
The 50 miles at 55 MPH is probably on the conservative side. If you're on the road, stop at the nearest place and have a quicky plug installed. When you get back to home base have your tire guy install a "speed rated" patch/plug, which will require removing the tire from the wheel.
Not sure about Corvette guys, but I bet that over 50 percent of drivers on the road today would NEVER attempt to change a flat tire. They'll call AAA.
Duke
12-14-2004, 10:24 PM
#22
Safety Car
Originally Posted by Scissors
I have no idea.
But Y rated tires are good only up to 186. Z rated is good for 155+ (leaves a lot of leeway.)
But Y rated tires are good only up to 186. Z rated is good for 155+ (leaves a lot of leeway.)
"When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W 168 mph 270 km/h Exotic Sports Cars
Y 186 mph 300 km/h Exotic Sports Cars "
Therefore, Y is the highest rating available. For the full info, see:
Speed rating info
12-15-2004, 09:16 AM
#23
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St. Jude Donor '06
Have to Share This
I posted the question on the C5 tech board as well. Got this response from Mike:"Run Flats are for blondes who think AAA is a brunette bra size!"
Too cool
, had to pass it on.JT
12-15-2004, 09:19 AM
#24
☠☣☢ Semper Ebrius ☢☣☠
Originally Posted by fdxpilot
Scissors, you of all people should know this. Z rated tires have been out for around 20 years. They are rated at 149 mph+. at the time, street production cars just didn't go much faster. The Tire rack website contains the following info:
12-15-2004, 10:49 AM
#25
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Originally Posted by ivan111
So that means that there is going to be a grip or handling compromise in the new Z..... 
If the new Z06 wants to outhandle its main competitors it has to use regular tires....
If the new Z06 wants to outhandle its main competitors it has to use regular tires....
12-15-2004, 01:04 PM
#26
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Originally Posted by fdxpilot
Scissors, you of all people should know this. Z rated tires have been out for around 20 years. They are rated at 149 mph+. at the time, street production cars just didn't go much faster. The Tire rack website contains the following info:
"When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W 168 mph 270 km/h Exotic Sports Cars
Y 186 mph 300 km/h Exotic Sports Cars "
Therefore, Y is the highest rating available. For the full info, see:
Speed rating info
"When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W 168 mph 270 km/h Exotic Sports Cars
Y 186 mph 300 km/h Exotic Sports Cars "
Therefore, Y is the highest rating available. For the full info, see:
Speed rating info
12-15-2004, 01:12 PM
#27
☠☣☢ Semper Ebrius ☢☣☠
Originally Posted by ivan111
Interesting the Carrera GT tires are Z rated and are capable of over 200 mph......
Z rated tires, however, just have to be tested to 149. But Z is a catch-all category that includes anything above this that doesn't match the other ratings. That's why Z is the only one that has the plus. They're 149+ (i.e. tested to 149 or better.)
12-15-2004, 02:23 PM
#28
Safety Car
Originally Posted by ivan111
Interesting the Carrera GT tires are Z rated and are capable of over 200 mph......
12-15-2004, 03:58 PM
#29
Le Mans Master
Originally Posted by JFTaylor
OK we don’t have a spare. Dealer told me that loss of air pressure means no more than 55 mph for 50 miles. After that, loss of the tire is expected. Which means that unless you’re in a war zone, you stop when you get a flat and call for help. So why the Run Flats? From what little I know:
1. Run Flats add $100 per tire. And more important:
2. Add weight. I’ve been told that “un-sprung weight” is bad – bad.
3. Make sense that a non-run flats have a more flexible sidewall – thus handle better.
So when it’s time to buy why not get regular tires and carry a can of Fix-a-Flat??
I'm posting on the C-5 board too.
Will use of Fix-a-Flat damage the pressure sensor inside the tire?
1. Run Flats add $100 per tire. And more important:
2. Add weight. I’ve been told that “un-sprung weight” is bad – bad.
3. Make sense that a non-run flats have a more flexible sidewall – thus handle better.
So when it’s time to buy why not get regular tires and carry a can of Fix-a-Flat??
I'm posting on the C-5 board too.
Will use of Fix-a-Flat damage the pressure sensor inside the tire?
12-19-2004, 05:57 PM
#30
Originally Posted by DT
Howdy!
The "next gen" runflats seem to offer much better overall performance. I consider a runflat a "street" tire anyway, where the limits of a runflat are still way beyond what you should be doing on public roads.
To be honest, I really don't like driving a vehicle that doesn't have either 1) a conventional spare or b) runflats. You might notice from my sig I drive a Z06 which has neither. I plan on going to some Michelin runflats very soon (SRT Viper OEM's in fact). (I'll keep my CCW 18's as dedicated track wheels/tires)
I agree 101% with the "...you don't want to get stuck in..." comment, especially when we take the Vette on a road trip. I know there's always AAA, but I'd prefer not to me left waiting, especially if the wifey is with me, in a "bad situation". (There's always the combo of AAA+S&W but that's another whole can of worms )
I firmly believe the slight performance penalty is offset by all the safety benefits. FWIW, I've read a number of stories of people driving much farther than 50 miles on an EM type tire, YMMV of course.
The "next gen" runflats seem to offer much better overall performance. I consider a runflat a "street" tire anyway, where the limits of a runflat are still way beyond what you should be doing on public roads.
To be honest, I really don't like driving a vehicle that doesn't have either 1) a conventional spare or b) runflats. You might notice from my sig I drive a Z06 which has neither. I plan on going to some Michelin runflats very soon (SRT Viper OEM's in fact). (I'll keep my CCW 18's as dedicated track wheels/tires)
I agree 101% with the "...you don't want to get stuck in..." comment, especially when we take the Vette on a road trip. I know there's always AAA, but I'd prefer not to me left waiting, especially if the wifey is with me, in a "bad situation". (There's always the combo of AAA+S&W but that's another whole can of worms
)I firmly believe the slight performance penalty is offset by all the safety benefits. FWIW, I've read a number of stories of people driving much farther than 50 miles on an EM type tire, YMMV of course.
The Gen II runflats on my MS C 6 are better than the Gen I's. Still, I'm hoping Michelin will have Pilot Sports to fit the C 6 at the first required tire replacement, I will switch immediately and count on AAA and an air pump. The performance difference is worth the risk.
12-19-2004, 07:41 PM
#31
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Originally Posted by Mike S
The Gen II runflats on my MS C 6 are better than the Gen I's. Still, I'm hoping Michelin will have Pilot Sports to fit the C 6 at the first required tire replacement, I will switch immediately and count on AAA and an air pump. The performance difference is worth the risk.
12-19-2004, 09:53 PM
#32
Race Director
Would you feel safer with or without runflats on your teenage daughters (or wifes) car (yes she could be driving your Corvette, you never know)?
Having her broken down along side the road with some pervert stopping under the guise of 'helping out a lady in need'? Thats how rapes and murders happen.
Next, if Im in the 'hood. I dont want to be stuck changing a flat tire. Im sorry. Sure you can avoid the hood, but Id rather be able to go thru it knowing that I can make it thru to the other side.
Second, with police using stuff like 'spike strips' Id rather be driving a runflat tire equipped car than a non runflat tire equipped car. Sure, flat runflats will slow you down, but youll at least stay moving thru any type of police/criminal/or terrorist situation. Im just kidding here about the police part, I always wonder how much further criminals would make it on runflat tires when spike strips are used. (all the spike strip makers claim their devices disable runflat tires, but ive seen data from NLECTC (they test law enforcement items like bulletproof vests) that shows otherwise, under certain circumstances.
Quote: Depends on the runflat. Michelin's PAX system of runflats doesn't require a stiffer sidewall. It does, however, require a special rim.
I work in the tire industry and will tell you Michelins PAX system flat out blows.
First off...you wouldnt think conventional runflats had much of a weight penalty if you knew how much a PAX system weighs. (special rim + inner support ring + tire).
Second, cost. You think runflats are expensive? Try with PAX. You need special rims, which there is not a high volume of. You also need to buy the inner support ring, which costs just as much as a non-runflat conventional tire, and special lubes that need to be applied to the inner support ring.
Next, if you think PAX system rides better than runflat....usually it does, this is its only advantage. However, if you hit a pothole and bottom the tire out against the insert, its like you are riding on a solid steel!
Finally, if your tire does go flat, a PAX tire handles like complete garbage, whereas a runflat tire (while still losing quite a bit of performance) retains more of its non-flat handling characteristics.
Now, all that said Michelin had some amazing concepts for AIRLESS non-pneumatic tires that were mind boggling. Thats truly the future. We're not there yet, but its coming.
Having her broken down along side the road with some pervert stopping under the guise of 'helping out a lady in need'? Thats how rapes and murders happen.
Next, if Im in the 'hood. I dont want to be stuck changing a flat tire. Im sorry. Sure you can avoid the hood, but Id rather be able to go thru it knowing that I can make it thru to the other side.
Second, with police using stuff like 'spike strips' Id rather be driving a runflat tire equipped car than a non runflat tire equipped car. Sure, flat runflats will slow you down, but youll at least stay moving thru any type of police/criminal/or terrorist situation. Im just kidding here about the police part, I always wonder how much further criminals would make it on runflat tires when spike strips are used. (all the spike strip makers claim their devices disable runflat tires, but ive seen data from NLECTC (they test law enforcement items like bulletproof vests) that shows otherwise, under certain circumstances.
Quote: Depends on the runflat. Michelin's PAX system of runflats doesn't require a stiffer sidewall. It does, however, require a special rim.
I work in the tire industry and will tell you Michelins PAX system flat out blows.
First off...you wouldnt think conventional runflats had much of a weight penalty if you knew how much a PAX system weighs. (special rim + inner support ring + tire).
Second, cost. You think runflats are expensive? Try with PAX. You need special rims, which there is not a high volume of. You also need to buy the inner support ring, which costs just as much as a non-runflat conventional tire, and special lubes that need to be applied to the inner support ring.
Next, if you think PAX system rides better than runflat....usually it does, this is its only advantage. However, if you hit a pothole and bottom the tire out against the insert, its like you are riding on a solid steel!
Finally, if your tire does go flat, a PAX tire handles like complete garbage, whereas a runflat tire (while still losing quite a bit of performance) retains more of its non-flat handling characteristics.
Now, all that said Michelin had some amazing concepts for AIRLESS non-pneumatic tires that were mind boggling. Thats truly the future. We're not there yet, but its coming.
12-19-2004, 10:06 PM
#33
Team Owner
Originally Posted by Scissors
But all of the good intel I've heard is that they're 325s. I don't know where this 345 stuff came from.
12-20-2004, 03:45 AM
#35
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If you are not on the track, I think the second gen of run-flats is a damn good compromise for real world driving.
To add to dizwiz's comments, Bill Cosby's son Ennis would still be alive if his Mercedes SL600 had had run flats. He had to stop and change a tire on an entrance ramp in LA and was murdered. Makes the tiny difference in street performance between gen II runflats and regular performance tires seem like maybe it's not such a big deal.
To add to dizwiz's comments, Bill Cosby's son Ennis would still be alive if his Mercedes SL600 had had run flats. He had to stop and change a tire on an entrance ramp in LA and was murdered. Makes the tiny difference in street performance between gen II runflats and regular performance tires seem like maybe it's not such a big deal.
12-20-2004, 07:46 AM
#36
☠☣☢ Semper Ebrius ☢☣☠
Originally Posted by TA
I think that since the Viper rides on 345 rears, that people assumed that the new Z06 would be the same.
