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Last year I was running on some old Hoosiers but this year went with new Hankooks and had a heck of a time keeping it on the track. The Hoosiers started at 32psi cold but when I tried 32 psi on the Hankooks, I was oversteering all over the place. Some of it was probably the 40 degree track temp, but I think I had the most off track excursions out of everybody.
Any ideas for cold tire pressures for the Hankooks?
Thanks.
We found that dropping the starting pressures by 2lbs worked.Quote:
Originally Posted by Ralf
Cold tire pressures are tough to guess because there are a lot of factors that play into how much pressure gain you will get for a hot pressure. Nitrogen vs air, water content (even with N2, unless you are purging the tires) and even setup/driving style will have some effect.
My experience has been to get hot pressures between 42-44 psi which for me typically means starting at 35-36 front (FWD so more heat) and 38 rear but your mileage may vary. That is with N2 but without multiple purging cycles to drive out all the moisture.
Cold pressures are just a guess to hit your target pressures. They have no real value. The hot targets, are what matters. On a hot day the colds #s, are closer to the hot #s.
A road course has a dominant turn direction. Right . for most. My LF cold pressure may be 27, RF may be 29, LR 38, RR 39. MY target pressures are about 33-4 front, and 40 RR ,38LR.
Run the car 3 laps ,set the fronts to mid 30s, and go from there.
If the car is loose, lower the rears , but not under 30#.
You want max front grip, and you want to be able to adjust the rotation, by rear pressures.(less rear grip).
MM
Hankook says 40 Hot and a couple of pounds less for light cars
Ok, sounds like I just started with too low of tire temps.
Here is my video of the morning qualifying session. I had already done one lap trying to get temps up and still had to tip-toe around the track. Track Temp was around 40 degrees.
[ame]http://www.youtube.com/watch?v=OGIwr7PYREg[/ame]
The race was much better with higher front pressures.
[ame]http://www.youtube.com/watch?v=3zGWRT8GmOs[/ame]
Ralf, I just ran Hankooks this weekend and loved them. Go to the Hankook site and read the motorsports technical information. The Hankooks require much higher pressures than the Hoosiers. The target pressure is 40psi for maximum performance.
Nice Vid Ralf,
Looks like the car still has a push. Watching the wheel, it is never open during the turns. Do you have my book? What are the spring rates and rear toe settings? There is a lot of speed left, IMHO. MM
The spins/OT seem to be gross tire pressure errors in the rear, maybe way to high rear pressure and or spring rates. You were going very slow and still went around. You need to keep power on as it slides.
Tire pressures were off that weekend. The next weekend I did some testing to get pressures and shock settings dialed in and the car handled much better. As far as still pushing, I kind of prefer it that way for the time being. Last year the rear end came around on me and I ended up hitting a wall. That's not good for the race budget. :(
My last race, I ended up being within .240 off the track record at Heartland Park. :happy204:
YouTube Video
This video shows footage from behind me and shows my half spin because I was braking, turning with the left side on the gators.
YouTube Video
I'll be on 275/40r17 Z214 C51 Hankooks next race. For the money and free shipping I couldnt pass them up. Either way I bet they'll be faster than the heat cycled out 2005 V710s that I was on!!!
I hope to be at MAM in June. Will have some more info about them after that. I plan to run nitrogen in them to help stabilize cold/hot tire pressures.
Anthony
Out of curiosity, is there any difference in wear at the "fast" (40psi) pressures?
Get my book, and get the record. I'll bet you the 20$, that you go atleast .5 sec faster on 1 min.
:>, MM
I already have your "Book" and don't believe I want the rear end that loose considering the fact that I don't have trouble getting the rear to step out with just tire pressures. Your setup is quite radical and has the rear end way loose. Right now I'll stick with what I have and work on getting experience. I'm pretty pleased with my time considering the track record was set by Chris Albin who runs an A3 and Hoosiers.
I can respect that. If you have a comfortable setting, why change it?
Track time and experience, is the first step to speed. Trying to continally go faster, is why we do this.
My setups would be be radical , IMHO, if it was untried. The speed increase is the result of working towards allowing the rear tires to do more, reducing the front tire loading.
Physics cannot be cheated. If the rear tire has more dynamic loading, than by deduction, the front tire has less. If the front tire has less, it can go faster, before becoming overloaded.
Does the DRS have negatives? Yes, it can be less precise than a hard rear end.
The same goes with running more rear tire pressure, along with less spring rate. It rolls cleaner, therefore it must be faster.
The zero scrub? Same thing, it rolls easier. Will you need to refigure and experiment with springs and tire pressures to get it all working. Yes.
Goodluck, MM
I used to run Hankook tires at 32lbs in the front and 36lbs in the rear. After that it was all about the Dampening. Getting enough bite into the corners. Check sidewall wear after each race for tire contact coverage.
With the Hankooks did you always run then with the direction arrow or did you swap them side to side?
Per Joe of TreadZone, make sure to follow the arrows. As I remember the explanation, the plies have a tapered overlap that is designed to be run in only one direction. If you want to run them on the other side of the car to even out wear you'll need to have them dismounted and flipped.
Alright, thank you.
I've rotated by criss crossing my tires with no ill effects...so far.
I have found two things. two much pressure will wear the tires very quickly We tried up to 44 and not only were they greasy they wore very quickly. My car is heavy (2750#) and like 38psi. The wear there is just fine.
I have also been able to cross rotate my tires. Once they have a couple good heat cycles in them the wrap shouldn't matter. I was always nervous to do this but had an engineer from Bridgestone tell me it is fine once heat cycled in. He told me all tires are wrap in a direction and that is where the direction arrows come from. He did go on to say if there was too much grip via aero or even mechanical it could change his statement. I don't think most of our cars will fall into that category...