Rode in a 426hp 4th gen camaro

[ryanprins13]

. I think as a community we are right on track. I'd love to send you some photos of my suspension setup to get your thoughts. A friend of mine who also makes custom racing suspension setups looked disgusted at the amount of weight in front of the front axle. A national level competitor as yourself. The counterintuitive aspects of this car are what fuel my love for it!

We would love to see your car! Youll be working on it so start a thread in the build section of the forum and add lotsa photos!
Lol, why? Thats how we get our power to the ground! Imagine a fwd motorbike... yould need weight in front of the front tire to keep it down so you can accelerate.

Ahh... just to throw another wrench in the gears!!

Taken from an autocross forum.



EDIT:

Adding another quote



Just a little bit of backup for my claims / skepticism. I'm still legitimately interested in testing my experiment between tires, so I think I'll still give it a shot.

Thinking about this more i realize that i want to learn a lot more about it [emoji14]

My first question would be how would you get a 6x4 and 12x2 patch on the same car? In the second quote it says wider tires have a shorter contact patch but isnt that because they have less psi on the contact patch to deflect them?
I think (but i dont know) that you would have to get a much taller and narrow tire to accomplish that difference on the same car and that would change a ton of other things.
Can you tell me how that works if im not understanding this?

The way i see it any tire with the same sidewall hight, made out of the same materiel and having the same diameter will have the same length of contact patch if you exert the force required to have the same psi on the contact patch regardless of width.
The reason wider tires get a shorter patch is because there is less psi to deflect the tire right?

Also its not quite as simple as he says, this tire will have a different contact patch size than this one because of the tread pattern:



And all this is about why wider tires are better. What if 185's are wide tires for our car?

With the slip angle- thats different for different styles of suspension and its why we use negative camber. So to put it basically lets say we have a 165 tire with lots of negative camber and the majority of the weight is only on half the "contact patch" at rest. That gives optimal accelleration traction because 165 is too wide lets say and the pressure would be too low. So essentially you have 1 tire width on the ground when your going in a straight line.
Then you go to corner and that negative camber flattens out on the outside tire so its level lets say. All the weight from the inside tire transferrs to the outside one and you have the same contact patch psi as you did going in a straight line. You also have the same contact patch size on the ground.

Wider tires giving more responsive handling and feel has more than just contact patch at play. Wider tires basically always stick out farther because you cant go in. Its like outriggers on a crane. Much more stable. If you took the narrower tires and put them on rims that stuck them out as far as the wide ones or used wheel spacers you would gain much (but perhaps not all) of the same feel.

Also optimum contact patch pressure is different on the same tire depending on what temperature the tire is. As it warms up it gets grippier to a point. Once it overheats you loose traction.
So toonarrow of a tire can overheat easy if you drive it hard, but too wide a tire might never warm up enough to give you optimal traction. Thats another reason for using different tire widths on non-awd cars.

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[ryanprins13]

Also, how is load transferred to the patch? Is it even? A lot of it comes down the sidewalls to the outside, how well does the air pressure inside the tire support the middle? Is there more pressure on the outsides and less in the middle?

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[Advancedynamix]

OMG this topic is crazy. Try the tire you want and come to your own conclusion. I listen to what charlie says because he has lots of seat time in the car (the same kinda car). I will make my mind up as to what tire is best for me and my situation but i will start off with what he has suggested or i will get as close as i can to that.

Sometimes at the end of the day it all comes down to what works best! the math does not always paint a perfect picture.

Mike, your thread has sparked a great conversation. This is exciting stuff. You are right in stating that it's best to just go with what works for you.
Nobody is arguing here, just a great topic and some solid theories and information being exchanged. We all benefit from more people testing with more cars on more tracks.

[Advancedynamix]

Also, how is load transferred to the patch? Is it even? A lot of it comes down the sidewalls to the outside, how well does the air pressure inside the tire support the middle? Is there more pressure on the outsides and less in the middle?

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Yes, there are a lot of variables here. I have done a lot of back to back testing with many different race teams to determine tire width and compound, and at the end of the day, it's mostly a driver preference thing.
Maybe Ryal will chime in here. I've personally driven the cars for a few of his tire comparison tests. I know that there is a point where wider tires slow the car down. He uses a mazda2 for his testing, so that's pretty comparable to a Festiva.

You are also spot on with your comment about negative camber. I've found the sweet spot to be -3 to -3.5 degrees in the front and -4 to -5 (maybe more?) In the rear on 185mm tires. These cars work so much better with negative camber, and the tires last longer on the track.

[Dragonhealer]

^ Yes, i've been following with interest, Ryan's post #31 has opened the correct can of worms!
All the calculations i've made regarding tyres have only been mildly useful.
Too much tyre slows you down, too heavy, too wide, too sticky? Just an observed fact. Not enough tyre wears out too fast, example: we put 145's on Ethel (B3 5speed stock suspension) everything fine, very efficient. Then we fitted Advanced suspension and wore them out in 9K miles using the same sporting driving style.
Best track results on the Mazda2 is 225/45-15 front @40psi hot and 205/55-14 rear at 45psi hot. The tyres are Nitto NT-01's, but its not that simple. If the tyres were fresh, this wouldn't work at all, way too much grip. The tyres are take offs that have dried/aged 2-3 years. The stager is so they heat up similarly, the pressure developed to give best results. All of this is by trial and error.
My rule: Give the car what IT wants to go fast, not what I/you want.

[mikemounlio]

SO i will be racing this summer in overkill. How do i go about adjusting my tire psi? I will be on my federal 595 185 60 13 on my rims that are 6" wide. I will have to stay with this combo for a while at least so please dont just say get a different rim or tire!

Is it all by temp, roll of the tire or by feel or a combo of all? I am new to racing so ill be full of excitement. I wont really be able to feel anything i bet

I have seen the shoe polish on the tire and do a hard turn. look at the polish and adjust pressure. What am i looking for?

[Dragonhealer]

Wow, there is a whole book worth for that, but the process is straight forward :

[FestYboy]

I rather doubt the 145s were driven in the same manner once the new suspension was installed... I suspect once it was sorted, the loading on those 145s went through the roof. And the added heat generated would aversely affect the tread wear.

Not saying you drove (or thought you did) any differently, but the reality is it wasn't just the suspension that changed.

Too many damn variables!!! Lol

[FestYboy]

Also, we need to smack all our heads together and get a recorded teleconference going... There's just too much info to write down once the juices get flowing.

[Dragonhealer]

Oops.
You want to start on the safe side, and not muddy results with over heated tyres.
Road course: start with 36psi cold all 4, check immediately off track, adjust to achieve 40psi hot all the way around, you will have to adjust this each time. Note how the car handles, look at the roll-over marks, should be no wear on the marks, just up to is about right.
Be aware the rear tyres will take longer to get hot as there is less weight on them!!!
If the car is pushing, raise the rear 2 psi at a time till it feels neutral or slightly loose. If the car feels loose at 40 psi all around, something is wrong.
Auto cross: this one is all trial and error, and the tyres change the whole run. Try 28psi cold and raise the pressure in 2 psi increments on the axle that has too much grip (please share results) It is also possible to reduce pressure of the tyres on the axle with the least grip, but advise against going lower than 26 psi on the front at your power level.
Drag racing: someone else will have to advise!

Mike, there is more to this, but this will get you in the ball park fast so you will be having fun! Share your results and we can fine tune

[Advancedynamix]

I rather doubt the 145s were driven in the same manner once the new suspension was installed... I suspect once it was sorted, the loading on those 145s went through the roof. And the added heat generated would aversely affect the tread wear.

Not saying you drove (or thought you did) any differently, but the reality is it wasn't just the suspension that changed.

Too many damn variables!!! Lol

I may have had something to do with the accelerated tire wear. Lol. He told me to test it. I had never tried a decent set of 12" tires with the coilovers, and I had an open test track all to myself (well except for Carolyn driving Pedro and a brand new Viper ACR.)
I can say that the 12's weren't as bad as I thought they would be. I had fun lightly sliding Ethel on the little tires, but I came in after 5 or 6 laps. Carolyn wasn't real happy that I was testing our theories in her daily driver. She's way too nice to us.

[Team Lightning]

The factory Yokohama 145/12's handled very good in the mountains. I gave several Mustangs more than they wanted in the curves. Basically, I was faster in the curves but the V8 in the GT would get me in the straights. Just wish I knew then what I know now.

[Advancedynamix]

I think that Ryal had Yokahama 145s on Ethel that day. All my Festivas have come with garbage 12" tires, so that was the first time I was able to try a half way decent set of 12's (even though they were quite old, at least they were round.)

[Team Lightning]

The Yokos were the best 12" I ever had on it. I bought several brands until I changed it to 13's. I only found Yokohama's one other time over the years. Kelly-Springfields were among the worst. Had to be balanced every oil change. (3000 miles)

[Dragonhealer]

Yes, Charlie ran Ethel on the Yokohama 12's, only 12 inch we have found that works. I was delighted when they went back in production.
Put a set on Jim Anderson's (God)'s car, still perfect!

Wish I could show a pic of the front tyres on Ethel.