luvmy92

I was curious to know how much usage most of you are getting out of your Khumo V700 Victoracers? I have done 2.5 events on mine (about twelve 20 - 25 minutes sessions) and am already noticing less grip. This could be caused by a number of factors, one of which is I am driving more aggressive than I was in the beginning.

The car was very neutral when I put them on for the first time but I am now seeing a little bit of oversteer. The car got loose on me on 5 occasions at Sebring a couple of weeks ago and prior to that it felt very solid. My tire pressures were 35f/33r cold and they would heat up to 41f/39r after a session. For Sebring, I decided to go 33f/31r cold and I am wondering if that was the difference.

My alignment is as follows:

Front Camber: -1.7 degrees
Front Toe: 0
Front Caster: 6 degrees

Rear Camber: -1.2 degrees
Rear Toe: 1/16" in each side

My guess is I am probably just overdriving the car but would like to know how much of a role a couple of pounds of tire pressure plays in the overall handling of the car, and would really like to know what to expect out of a set of tires.

Thanks,

Mike

luvmy92

Nobody has any experience with these tires?

Mike

L98 DRIVER

my kumhos seem to go to mush after about 10 heat cycles
after that they are only used on a lot that we run on that is verry abrasive
I figure 1 heat cycle per solo event and 1 for each session on track
:cheers:

RX7 KLR

I always found the Kumho fast from full tread to cord. My Hoosiers on the other hand go off around 50 solo2 runs.
Also keep in mind track temp will effect your grip, to hot and you will start to slide. Try more rear toe in.


[Modified by RX7 KLR, 7:38 PM 8/11/2003]

rbeckham

Mike - Kumhos last a long time if you treat them tight. Your starting pressures are good, in my experience I find that pressures (and temps) rise quickly (depending on track conditions). With Khumos it seems to work better if I lower the tire pressures after the first session back to under 40 (can't tell you exactly what works - I run lower pressures) but my advice is to bleed them down to near your starting point after the first session or run unless your car will sit for a long time. Regards, Robert

larryfs

I found it neccessary to bleed down between every session. 34/33 on my 96
I have 7 track DAYS on my so far and all is great.

you just may be over driving the car.

John Shiels

The last set I had lasted about6 track days and maybe more if I didn't dissmount them they were about 18 months old as my motor blew last year. They didn't stick as good but were reasonable. The set before that started to come apart fast with major sidewall cracks so watchout.

luvmy92

Thanks for the replies guys! I guess I forgot to mention that it was about 97 degrees that day as well. I think one other thing I am going to try is to add some more camber to the rear. I am currently maxed out in the front at -1.7 degrees and am going to do the same at the rear (add -.5 degrees). Does anyone know what kind of effect this will have on the overall handling of the car?

I appreciate your input...

Mike

RX7 KLR

More rear -camber and more toe in is more rear bite. I use -2.5 rear camber and it puts power down great.

luvmy92

Thanks Jason. Just out of curiousity, what kind of camber are you running up front?

Mike

RX7 KLR

-1 drivers side -1.1 on pass. All that I can get out of a stock class car. :mad

luvmy92

Thanks again. I think there is at least another degree in the rear for me but was unsure if I should use it. I guess the propensity for these cars is to understeer but mine has always had a problem with oversteer if anything. If I went to -2.2 to -2.4 in the rear, I'm wondering if that might balance it again. I guess the only way to find out is to experiment with it and see what works.

Mike