Originally Posted by Evil-Twin

I spent 5 years developing and designing this car from 1995 through launch in 1997 and then two years of field debugging at the Engineering support level before retiring..I have seven designs in every C5 on the planet and collaboration in many other designs through failure modes effects analysis. FMEA's.

Originally Posted by Evil-Twin

I get 40,000 miles out of a set of tires, using this tried and true method of tire pressure tuning.
I got 43,000 miles out of my Original Goodyear F1's I could have got 45,000 miles out of them.

30 PSI COLD is for sissy's.

You have a factory built race car so treat it like all the professional pit crew do and that is set the tire pressure for the prevailing conditions.

Only Idiots would think that a cold pressure setting set at 30 PSI cold and would increase to 38 PSI on a 95 + day where surface temps on a black top road can see 140F.. and to those days when you set them in the afternoon to 30 PSI cold @ 35 F and it gets down to -20 at night in Fargo North Dakota, and can take your tires down to 26 PSI. And then give some logical reason why the actual temp of these two conditions one being 38 PSI and the other being 26 PSI both set at 30 PSI cold could result in no change in performance. Any professional race car driver will tell you that one psi can make all the difference in getting those few extra laps out of the tires or a few extra laps of fuel because the tires are performing at the proper pressure " HOT".. so for all the Idiots out there please use the idiot sticker.. 30 PSI Cold. no matter what the conditions of the actual use become. We called that sticker the idiot proof sticker at GM... because people were using the sidewall and putting 45 lbs of pressure in the tires only to have the DIC throw a code.

I wasn't going to do it again but I did... sorry.. its just a pet peeve ...

Originally Posted by Evil-Twin

I run my tires at 30 PSI HOT.. Always. Dont ask me why.. Ive already posted the reasons over 1 thousand times here on this forum over the last ten years.

Originally Posted by Evil-Twin

This is exactly to the point... when your cold tires @ 30 psi actually get their run temperature on a hot day and see 38 psi like they will on a 90/95+ day. the tires becaome convex ( grow in the middle because of extreme tire pressure created by the heat of the day). with the tires in this condition you lose 40 % of the footprint and contact patch, your ten inch wide tire patch is reduced to 6 inches, you lose traction and stopping performance.This also is the reason so many people here see the centers of their tires wearing out before the other 60 % of the tire.
If you want your car to perform like it should keep the tires at 30 PSI hot.. It doesnt matter what your tire pressure is when they are cold.. only when they are actually being asked to do what they were designed to do, run at actual driving conditions and temperatures. For many people a Corvette is a summer car. it can get hot in Texas, and Arizona , and Georgia.. those hot asphalt roads can fry and egg.. and increase your tire pressure dramatically.. You do not want to be running around with 38 psi in your tires.
The End

Originally Posted by BobAruba

Bill, I don't doubt your experience in most subjects on this forum with the exception of your discourse on proper tire inflation.

I guess the six months I attended Goodyear's Tire Instruction Course didn't amount to too much, huh?

I guess Goodyear's instructors and engineers with decades in the business of tire construction and longevity were way off, huh?

Bill, it is not my intention to cause you any distress but my, according to you, "misguided opinion" has been shared with most motorheads and track guys I've been associated with for the past fourty years.


Good luck to you,
Semper Fi!
Huurraah!
Bob

Originally Posted by Evil-Twin

Bob do what ever makes you happy.. but if you think that its the job of a specific member of the Pit crew in every NASCAR, Formula 1 team to monitor track temps and adjust the tire pressure accordingly. 1 psi can make tires wear prematurely and cause enough drag to lose a few laps because of fuel economy, and become loose in the corners because the track temps have increased the tire pressure. if you think running a tire at 38 psi can produce the same results as a tire at 26 psi, you wasted your time and money at Goodyear's school. Everyone who has thanked me over the last ten years for following my tire pressure tuning recommendation has seen better fuel mileage, and better tire lonevity..and much better performance. AS many have attested... a cold tire at 30 psi can see 38 when they actually get out on that 140 F asphalt highway.. if you don't think so you never checked the variance in your tire pressure between cold settings and actual up to temp pressure.
Bob you have been a cop for 30 years, Ive been an Automotive engineer for 45 years. Ive also been a Motor head for 50 years.

Originally Posted by Evil-Twin

I spent 5 years developing and designing this car from 1995 through launch in 1997 and then two years of field debugging at the Engineering support level before retiring..I have seven designs in every C5 on the planet and collaboration in many other designs through failure modes effects analysis. FMEA's.

Originally Posted by thisMSGgood4me

That is a load of crap. What you're saying is that only 60% of the tire is in contact with the pavement. IF that was true, I should be able to get down on the ground in front of or behind my Vette and see daylight between the tire and the ground along the outer 20% of the tread on both sides of the tire. That's just simply not the case. 100% of the tread is still in contact with the pavement even under your exaggerated condition. Saying there's only 6 inches of pavement contact on a 10 inch wide tire is a load of crap.

Originally Posted by Evil-Twin

Bob do what ever makes you happy.. but if you think that its the job of a specific member of the Pit crew in every NASCAR, Formula 1 team to monitor track temps and adjust the tire pressure accordingly. 1 psi can make tires wear prematurely and cause enough drag to lose a few laps because of fuel economy, and become loose in the corners because the track temps have increased the tire pressure. if you think running a tire at 38 psi can produce the same results as a tire at 26 psi, you wasted your time and money at Goodyear's school. Everyone who has thanked me over the last ten years for following my tire pressure tuning recommendation has seen better fuel mileage, and better tire lonevity..and much better performance. AS many have attested... a cold tire at 30 psi can see 38 when they actually get out on that 140 F asphalt highway.. if you don't think so you never checked the variance in your tire pressure between cold settings and actual up to temp pressure.
Bob you have been a cop for 30 years, Ive been an Automotive engineer for 45 years. Ive also been a Motor head for 50 years.

Originally Posted by Evil-Twin

You see Randy and Kenny why I don't post in these threads anymore.. when I say 60 % it means that the down force has been diminished because the center of the tire is seeing most of the down force and while the outside of the tire is in contact with the ground.. simple pressure transducers are actually used to test the actual footprint. the whole contact patch should see the dame down force, but if the tire is over inflated, the center sees most of the down force and is the reason the centers wear out before the outside.. and nobody could see any daylight through those tires either.. so your logic hold about as much crap as the diapers you must wear.
So take your load of crap and wipe your *** with it.. I am done in this thread.. See what I mean about all the idiots.. and their unsupported knowledge, and can you see why we had to put that idiot proof sticker on the car.
The Old ET

Originally Posted by bighank

Before buying my Michelin PS A/S ZPs I called Michelin. They advised me to add 4 or 5 pounds MORE to the tires so like 34 or 45 pounds cold.
I have been doing so for over 3 years and have not found any evidence of wearing out the tread in the middle which you might think would happen.
Try calling them and see what they say today.
BIGHANK

Originally Posted by thisMSGgood4me

That is a load of crap. What you're saying is that only 60% of the tire is in contact with the pavement. IF that was true, I should be able to get down on the ground in front of or behind my Vette and see daylight between the tire and the ground along the outer 20% of the tread on both sides of the tire. That's just simply not the case. 100% of the tread is still in contact with the pavement even under your exaggerated condition. Saying there's only 6 inches of pavement contact on a 10 inch wide tire is a load of crap.

Originally Posted by 00Corvette

you're incorrect..WAY LESS than 60 percent of a tire is EVER in contact with the pavement.

and you CAN SEE DAYLIGHT under neath the outer/inner edge of a tire in a high G situation.

go out to your car just sitting on the ground and slide 2 pieces of paper under your tire one in front and one in back. measure the distance between the two pieces of paper, then multiply by your tread width.

thats only sitting still...once you turn, it immediately drops the amount of contact patch in contact with the surface.

100 percent of the tread is NEVER in contact with the ground.

Why don't you check out your alignment specs and look for an area called CAMBER..if it's not 0 degrees, your tire isn't 100 percent flat on the ground period

Originally Posted by Evil-Twin

You see Randy and Kenny why I don't post in these threads anymore.. when I say 60 % it means that the down force has been diminished because the center of the tire is seeing most of the down force and while the outside of the tire is in contact with the ground.. simple pressure transducers are actually used to test the actual footprint. the whole contact patch should see the same down force, but if the tire is over inflated, the center sees most of the down force and is the reason the centers wear out before the outside.. and nobody could see any daylight through those tires either.. so your logic hold about as much crap as the diapers you must wear.
So take your load of crap and wipe your *** with it.. I am done in this thread.. See what I mean about all the idiots.. and their unsupported knowledge, and can you see why we had to put that idiot proof sticker on the car.
The Old ET

Originally Posted by Evil-Twin

Bob do what ever makes you happy.. but if you think that its the job of a specific member of the Pit crew in every NASCAR, Formula 1 team to monitor track temps and adjust the tire pressure accordingly. 1 psi can make tires wear prematurely and cause enough drag to lose a few laps because of fuel economy, and become loose in the corners because the track temps have increased the tire pressure.

Originally Posted by Atok

Racers do not adjust tire pressure for fuel economy, they adjust pressure for two reasons: 1) Primarily... wheel rate. 2) Contact patch (maximize grip). Especially in F1, the spring rate of the tire is more important than the spring rate of the suspension.

You can't compare what racers do to street use. Race cars are working their tires to the extreme, with very high loads, slip angles, etc. The tires will build lots of heat doing this - they are designed to. Also, heavy braking puts huge amounts of heat into the tires. A race tire may go from an ambient temperature of say 90 degrees up to full race temperature in the middle of a high-G turn of say 220 degrees. They may build 10 - 15 psi in pressure. Street tires may go from ambient of 90 degrees up to maybe 110 degrees and build maybe 3 - 5 psi. No comparison.

Engineers from both the manufacturer and tire supplier work together to design a "perfect" match for the car. If they recommend 30psi cold then that's the correct pressure for normal driving. I have always run Michelins on my Corvettes (since I don't pay for them ). Over the years I found 28psi rear and 30psi front COLD work well for tire wear which is most important to most folks.

Originally Posted by thisMSGgood4me

So you must be calling your fellow Vette engineers idiots, because that's who made the recommendations to set the tire pressure at 30 psi COLD.

By the way, I set my tire pressure according to this recommendation, and I've driven on roads when the outside temp is above 100 degrees, and my tires reach 35, maybe 36 psi at most, not 38 like you claim.