What questions would you ask?
We're discussing a future GRM Live! appearance with a tire engineer friend of ours. This tire company makes race and street tires. You have (hopefully) noticed their ads in GRM. I have personally known said engineer a long time, too.
Our friend asks: What do people want to know about tires?
So, what questions do you have? If we get some good ideas, perhaps that can help shape a future show.
Thanks.
I always want to know the correct pressure. Since I know that's a process, I want to better know the process to find the best pressure before I'm completely done with my autocross runs for the day.
If I wanted to make a special size radial tire , how much does the mold cost ?
there are only cross ply tires available in this size !
How should we store (or not store) mounted tires?-- temperature, orientation, pressure preference, etc.
If on a vehicle in storage, do we really have to worry about permanently flat spotting the tires?
When/where can i get some vintage racing tires for a 16x4 wheel
mazdeuce - Seth said:I always want to know the correct pressure. Since I know that's a process, I want to better know the process to find the best pressure before I'm completely done with my autocross runs for the day.
When I used to sell tires back in the '70's Michelin published a data book that showed the optimal radius from the center of the axle to the ground needed for the best contact patch. This took into account sidewall deflection. They also published inflation pressures vs. load applied so you could get to that optimal radius for any load. Or you could just inflate until you reached that radius. I don't think anyone does this anymore. I talked to an guy from Falken once and he had no idea what I was talking about. He said he was a tire engineer but I doubt it.
Of course this method is for regular driving, not autocross. At one time MIchelin claimed that inflating their tires over the recommended pressure made them too responsive to inputs and therefore harder to control in track or autocross situations..
Why is a larger (wider) tire contact path better for handling / traction? (assuming the same tire compound)
Both a larger and smaller patch have the same weight on them (thus the same side loads) with the smaller one having more pressure per square area (inch cm etc) which would naturally have more grip (pushed down harder) seemingly compensating for the smaller area.
Good questions. Keep them coming. Thank you. And hopefully no exploding heads that evening.
How much worse is a low spec tire (500+tw allseason) than a ST* tire in straight line braking, assuming all other variables are held equal?
aircooled said:Why is a larger (wider) tire contact path better for handling / traction? (assuming the same tire compound)
Both a larger and smaller patch have the same weight on them (thus the same side loads) with the smaller one having more pressure per square area (inch cm etc) which would naturally have more grip (pushed down harder) seemingly compensating for the smaller area.
Its a lever arm and defection thing. The contact patches will have the same area but the wider tire provides a wider lever arm against the roll center.
The lower profile means less deflection in the sidewall.
In reply to aircooled :
It has to do with the tires' load sensitivity. Generally speaking, the lower the force per unit area that the rubber has to deal with the greater the grip in proportion to that weight.
I would want to know what the optimal camber and tire pressure would be at any given amount of load. Put it in chart or table form or even a mathematical formula. This information would be GOLD for anyone serious in amatuer motorsports.
What exactly does freezing temperatures do to modern 200tw autox tires? Can the tires be frozen if not inflated? Can they be frozen inflated if not supporting the weight of a car?
I always hesitate to buy tires for my autox car before the season starts because the risk of freezing.
Why are tires that list as a certain size not all the same? Different companies make, say, a 225/75R15, with the only true commonality being the wheel diameter.
How do rim diameter effect handling and stability on a motorcycle? Example:if I change the rim from a 16in front and rear, to an 18in rim front and rear, assuming the same tread with and compound, what should I expect to notice?
Should you tune to tire temps for optimal grip across the tire and then learn to drive the car using in theory all the grip (what I have done and proved to be faster) or tune the car to the driver and then adjust temps as much as you can with pressures. This has proved to be slower As a crew chief option one only works with a really good driver that is willing to adjust there style to maximize the tires ability where as lesser talented drivers you need to tune the car to there needs and they are generally slower.
Why aren't there more colored automotive tires? Is it due to the composition of the tires (carbon black)?
I'd like some crazy colored tires like BMX bikes had back in the '80s 
Rubber is white. I am not sure what color the synthetic rubbers are.
stanger_missle said:Why aren't there more colored automotive tires? Is it due to the composition of the tires (carbon black)?
I'd like some crazy colored tires like BMX bikes had back in the '80s
Those colored BMX tires had a big difference in grip. Owning a BMX shop at the time I tried various tires on ramps/trails/tracks/street and found no matter what brand/model of tire the colored ones had less grip than the black ones.. The only ones I liked at all were the gum Tioga Comp III's but they wore out fast. I warned a very fast buddy of mine who wanted to race on white Tioga comp III's instead of the black one's that were the standard 20" race tire at the time. First asphalt turn he hit he slid right out and went down hard. Colored tires really sucked on ramps.
A candid discussion of the tread wear ratings would be good. It's my understanding that the tread wear ratings are still a number each manufacturer comes up with on their own vs. something that is tested by a 3rd party so that all tires are subjected to the same test. I said when all the 200 TW regulations came about for certain events and/or classes that manufacturers could just make a 140 TW tire and give it a 200 TW designation so everyone would use their grippy tire.
Hoosiers are awesome. But given their incredibly short lifespan why do they cost so much? A friend who races dirt ovals runs Hoosiers and they cost less than half as much as A7s. I’d buy a lot more of the things if they were $100 each instead of $275 per.
My question is when will Coker make a reproduction Sumitomo HTR200. Ok i'm kidding.
What's the optimal tread/section width to wheel width relationship, and why? I've seen bazillions of opinions on the subject, but seldom any data to back them up.
Why do they always go flat on the bottom?
KyAllroad (Jeremy) said:Hoosiers are awesome. But given their incredibly short lifespan why do they cost so much? A friend who races dirt ovals runs Hoosiers and they cost less than half as much as A7s. I’d buy a lot more of the things if they were $100 each instead of $275 per.
I bet they sell more dirt track tires than autox tires, plus in fewer sizes.
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