Air down to what psi? Kumhos?

[Pewter2K1]

I have 255/50/16 kumho's and right now they are at 36 all around, I went down to 30 tonight while cruising, I can still spin them off the line, should I go lower?? I dont wanna hurt the rubber too much and possibly slow me down anymore with the extra rubber on the ground... Any opinion are appreciated, also, I imagine if I heat them up a bit before I run a bit that would help???

[12secondv6]

Well, are we talking street or track?
Street my tires are at 33 psi, yes I spin.
Track 30 psi.
Do you just floor it?
Maybe practicing just hitting it half way and then flooring it?
Trailing arms?
What is the traction and temp rating on them?

[Pewter2K1]

I am doingthis on the street right now, but Friday I am heading to the track and I dont wanna spin there. i believe the rating is a 300AA with another A for somthing else, thats probably temp. I am wondering aabout this because i had the stock Eagle GA's 235's and they wouldnt spin at all on the street. I guess this is a trial and error on friday.

[pgriffith]

Air PSI and launch is always trial and error. It will take you a few launches to get it right. Start high, then if you spin lower PSI. If you keep spinning maybe its not the right tire. So then try different things when launching. I found on my Cooper Cobra's they like 30 PSI and a 3,000RPM launch with my manual. I do spin but I get out of the whole kinda quick. I got a 2.0 60' time with this.

[Redsix]

LCA & PHR. This will make a world of a difference on your launch. [img]graemlins/evilgrin.gif[/img]

[jonny985]

I agree that you should just take a few runs and try diffrent tire pressures and launch rpms.

With my manual I find it better to start off at a lower RPM and work my way up, instead of working my way down. I'd rather bog then give it gas as opposed to spinning the hell out of the tires and tring to recover.

Its all trial and error, every car is different

[greenasgrass]

post some pics of the 255's, curious to see how they look.

[MustangEater8251]

WHAT kind of Kuhmos do you have?

Form my understanding kuhmos have stiff side walls, so when you decrease aire pressure actually the middle of the tire deflates, since the sidewalls of the tire are holding the wheel up. With those tires you are probable better to keep them up at 35 psi.

[strobhen]

I just about gaurantee that he has kumho supras

and I have heard the exact opposite about supras. They have softer sidewalls, and are more of a drag racing tire.

least that is what Dominic said [img]smile.gif[/img]

[Pewter2K1]

I have supra 712's, these do have a stiff side wall and they dont air down to well. I gave up on this adventure and just bounght some salad shooters and put my old eagle GA's. those tires do me fine for racing, at 27 psi. I will leave the rubber on my Kumhos. They are awesome for corners and stuff but not off the line. my 60' were like 2.3 with the kumhos. ubut i am at 2.19 with the GA's. the kumhos also seem to take some MPH's out of my top end my 1/4 has dropped a tenth and about 2 mph. not a big deal, still running 15.4 or less. :D I'll ahve some pics as soon as they get developed

[AZ3.8Camaro]

I put my 712s at 20 psi and had NO PROBLEM with tire slippage, but I had wheel hop like you would not believe. Felt like I was 4 wheeling.