pats

Hello.Looking for any and all input.First;the car-06 gt auto.c&l street cai with bama 91 octane tune.3:73 gears,roush rear springs,che lca's with relocation brackets.The dillema-I recently upgraded to Nitto nt 555 tires(255/50/17) in the hopes of better traction at the track.I'm not ready for dr's yet and these seemed to be a popular choice.
Observations;while I've only been to the track once with these tires,and it was cool out,and it was only days after the tires were installed,and the track wasn't prepped the way it usually is,I wasn't hooking worth a darn.Even just '2 footin'it(no rev build up),I was just spinning off the line. Observation 2:On the street,on most roads,even at 30mph if I do a "soft" kickdown to passing gear(just enough peddle for the tran to downshift),I can see the car leave 10 to 15 ft of black tire marks(no squeeling). Questions:For those running these tires,what pressure do you run them at on the street?;and at the track?Was my choice in upgrade not the best?I do find them a quieter and smoother riding tire then the stock Pirelli's.For those interested,with the nittos,best time was:60':2.003,1/4:13.47@101.2mph.Thanks for any and all input.(Previous best with the pirellii's was 2.02 60',13.44 1/4.)Also,for those with autos and these gears,what revs are you at going through the lights?

ski

Nice times for street tires!
IMHO, the only ways that you may be able lower your 60' time is either reduce the rear pressures to 22-26 psi, and/or to race at a well prepped track.
Don't have any info on your Nittos, but reducing the stock Pirelli's to 22-26 psi has helped some owners to improve their launches.