Race Tire Setting

[Morris]

Thought I'd start a thread about Race tires and how they need to be set up.....

This is how we use to set up the car before each race.... Right or wrong.... it worked for us.... I'm sure things are different today.... with all of the new technology introduced in the last 10 years...

-- Fill the tires and measure the circumference of the tires .... get the fronts to match each other and the rears to match each other.... set the smaller one out in the sun for 30 minutes and it will grow to the size you need...

--Now that the fronts and the rears match....set a ride height... usually you'll want 3/4" rake to the chassie front to rear.

--Now put the car on scales and weight each corner and figure what you want on each corner... remember weight transfers diagonally.... Also keep in mind how many right hand turns you have and how many left hand turns you have.... this will influence the corner weights....also have a driver in the car when doing this.... or a bag of sand....and sway bars must be disconnected...

--Set your Toe and Camber .... this is just a static setting.... you will change this at the track.... Castor is always built in or adjusted to as much as you can get..... 5 degrees is good..

--Remove the air and install nitrogen.... I think they have devices that will vaccum out the air and replace it with Nitrogen ....
Nitrogen doesn't have any moisture in it..... tire won't grow from the moisture in the air...

--Run the car as hard as you can and come in and get tire pressure readings and Tire Temps.... if it's a mostly right hand corner track ... do the left front first then the left rear then the right rear then the right front....
Those temps and pressure will tell you what to change.... cross weights .....raise one corner or the other to add temp and weight.......

--Change the sway bar settings based on the front to rear temps...

--Change the starting pressure .... maybe you came in and the temps were to high in the middle of the tire...

--Temp across the tire will tell you what to do with the camber.... also a Radial tire like alot of Neg Camber..... Bias not so much...

There's lot's more involve to talk about but this will get folks thinking about how to approach a set up and what to do when they get to the track and interrupt what the tire temp tell them ...

Just some thoughts and I'm sure there's many more folks that can add alot to this...

Morris

[scottj]

Moved from Shelby Aluminum thread

Originally posted by Morris


Hi Scott

I would think that the tires are old .....anything past 3 heat cycles is hard to get the tires up to normal range.....

Normal range is 200-210 degree's.... were the tires radial or bias??

Also what was the starting air pressure and ending air pressure.... also were you using Nitrogen... instead of air...??

Also I appologize for discussing suspensions on a motor thread...

Morris

Morris,

Tires were new Hoosier A3S03 radials, heat cycled by The Tire Rack, 335/35-17, 275/40-17.

cold: 36# rear, 38# front. My notes aren't in front of me but I remember the hot pressures to be 43 or 44#.

Air, not nitrogen... shame on me.

Maybe 15-20 minute sessions were too short?

Scott

[Morris]

Scott

You should only have about a 7-8 pounds build up of air pressure in the tire.... and I would want the tires to come in at about 35-38 pounds....

With IRS you can run alot more camber.....-2.5 to -3 neg camber and pressure will be somewhat lower....

Radial tires love neg camber.....

Also .... you should scrub in the tires.... don't let anybody else do a heat cycle for you.

15 - 20 min sessions are perfect for doing tire scrubbing in and getting a heat cycle in them...

The tire are the best when you go out on them the very first time.... but they won't last long..... they will over heat and go away.... Once you scrub the tires in.... let them cure over night or 24 hrs if possible..... they are good for the race and one more practice session.... then they will start going away...

Once you get the nitrogen in the tires .... you'll start to see the real tire temps..... with the tires blowing up with air.... they will never be flat on the ground....

Morris

[moneymanager]

I've recently purchased a BDR Cobra with the BMW IF & IR suspension and want to do some road racing. I'm considering a set of 17 X 10 wheels all the way around with Housier DOT A tires.
What would your thoughts or comments be on this combination?

Doc in Mesa, AZ

[Morris]

Doc

I'm not sure you could get the 10" wide front wheel in the wheel well..... but if you can and turn and not rub anything then it's a good way to go.... I think I'd try a 11" wheel in the rear....

On many of the cars we were racing .... we ran a 10" front and 12" rear

The Hoosier tires seem to be the best way to go and 17" is sure much better than a 15" wheel....

However a 18" is even better than a 17" wheel and the tire technology is being developed for the Corvettes and Vipers....

I'm haveing BBS make a set of 18" wheels for us and won't have them for another month... very pricey .... but work much better..

Technology waits for no one...

Morris

[moneymanager]

I have been looking for wheels but since my car has BMW brakes and rotors the Cobra R's won't work due to the 5 X120 mm bolt pattern required for mine.

What do you think of running 9"X17" wheels all the way around?

Got any asuggestions?

Doc

[ItBites]

Moneymanager

Talk to "GroupA" in Chandler. They helped me out with an oddball backspacing needed for the front of my Cobra with the C4 suspension.

The guy there is very creative and can likely help you out. I think we redrilled some 5X120mm pattern wheels to 5 X 4.75in and put steel inserts in them to get what I needed for backspace. Like I said he was very creative...

He can also build you a set of 3-piece wheels in any combination of width/backspace/bolt pattern you want. They are pricey though...

When deciding on wheel size, do not forget to carefully measure for correct backspacing. Max width is only OK if the center of the wheel is in the right place with respect to the hub flange.

Good luck. I'll see you at the track soon I hope!

[moneymanager]

Thanks that was helpful. I'll try to find GroupA and go from there.

Thanks
Doc

[moneymanager]

I tried lookiing up GroupA and found nothing. Can you be more specific who that is in Chandler?

HELP

Doc
(480) 641-9361 or 1-800-577-8057

[moneymanager]

I thought I'd give you an update on the tire and wheel search for my
BDR which takes (BMW) 5 x120 mm bolt pattern.

After MANY phone calls and research here is what I have ended up with:

I ordered 4 new ACIII wheels from http://www.team3wheels.com
in 17 X 8 and 17 X 9.5. They are being custom built now and should be
to me in 30 days, the 1/2 polished versions with NO spinners for racing.
The cost of the wheels will be $1730 plus shipping.

I also just ordered new HOOSIER's from Topless Performance in Phoenix,
as follows: R3S04 DOT race slicks in 245x45x17 for the fronts and
275X40X17 for the rears. Part numbers #46720 & #46730 from Hoosier.
The cost of the tires will be $956.00 mounted and balanced at Topless
Performance.

HOOSIER recommends setting up the car to run 2 1/2 degrees of
negative camber for best performance and tire wear.

I'm going to run at Vegas on Nov 4-7 at the Western Roudup so we'll see how this setup work with my BDR and the BMW Indep Suspension.


"Doc"

[tony martin]

HEY DOC,
JUST GOT BACK HOME, NICE TALKING TO U THE OTHER DAY.
IF SCOTT AT TEAM 3 HAS NOT STARTED YOUR WHEELS YET GET ON THE PHONE TO REG OR FRANK. THEY WILL GIVE U THE SPECS THAT WE RAN ON LAST YEARS RACE CAR. WE ALSO HAVE THE DIFFERENT SPRINGS FOR THE TRACK. IF U ARE INTERESTED WE WILL JUST HAVE TO RE CALC THE SPECS OF THE RIM SIZES AS YOUR FENDERS ARE NOT QUITE AS WIDE AS THE LATEST BODY STYLE. REG WILL TELL U WHAT TIRES WE RAN , THE PRESSURES AND THE SUSPENSION SET UP. (WE RAN IT ALMOST STOCK) HE WILL ALSO BE ABLE TO ADVISE U ON ANY OTHER SET UP U MAY NEED.
SHOULD U NEED TO CONTACT ME DIRECTLY U CAN MAIL ME AT: tony@trtec.co.za
I HAVE FOUND A TANK AND AM JUST WAITING FOR OUR ENGINEER TO SEE IF IT WILL FIT YOUR BODY. IF IT DOES I WILL SHIP IT WITH MY COMPLEMENTS AND FITTING INSTRUCTIONS.
GOOD LUCK

[Big-Foot]

Kumho V700 Victoracers - Tried all different pressures but 32 Hot seems to be right about it. This is about 26 front and 24 rear cold. These are 275-40-17 mounted on 17x9 rims on a Roadrace track like Blackhawk Farms.

[moneymanager]

Hi Tony,


I sure wish I had gotten your note sooner.


I called Reg and told him I had found a gas tank at Anthem Motors here in
Phoenix and they installed it in my car while I was gone on vacation for 2 weeks.
It is done now and cost me around $1,600 total for the full installation and
the tank.


If I had known that you had one and it wasn't going to cost me for it I would
have waited.


I got my new wheels and HOOSIER tires but haven't run them on the car yet.
They look great and TEAM II did a nice job on them.


Thanks for your offer -I wish I had known sooner.


Doc

[moneymanager]

Tony I tried your email address and it came back as OVERFULL.
It wouldn't work.

Doc