SaberD

went to the autocross today for the first time in my vette. the handling was OK in the turns, but i just couldnt give it barely any gas without roasting the tires. what peices of junk. cant wait to get my new tires. i was thinking about keeping these tires to trash in autocross, but now im having second thoughts. i heard you can lower the pressure in them to get a little better performance. anyone know how much this helps? it cant be too much better. im currently running them at 32 psi all around.

Barzten1

These are the sickest tires ever. Not much tread life but they grab like a pedaphile at a preschool! Toyo R888's

gonzalezfj

If these are the OEM tires that came in your 99 they are now 10 years old and probably hard as a rock.

Frank Gonzalez

AU N EGL

I agree with Frank.

tires should be within 2 years old. That saying drop the pressure to 28 psi and beat the crap out of them.

Tread life and "stickieness" are a direct opposite or contradiction.

The stickier the tire, the shorter the life. The Toyo 888 or the RA1s are a great compramise tire for street use, AND auto-x or track days

Gray Ghost GS

Look on the bright side - you were probably learning some valuable car control skills on them old tires.

davidfarmer

I think a lot of drivers have unrealistic expectations about low-speed driving in a vette. At full throttle in 1st or 2nd gear, you have 1000-3000ft-lbs of torque being applied to the rear tires. I'm sure your tires are crap, but you will need to develop very disciplined throttle control to manage your car on ANY tire.

I see a lot of former BMW drivers blaming the tires/handling/setup for what boils down to being used to driving a car with no torque.

Bill Dearborn

Both completely accurate. However, my experience with EMTs (although over 10 years old) is you can't drop the pressure very far. One thing that happens to the fronts (even at 30 psi) is a heavy wear pattern about an inch and a half outwards of the center of the tire. I suspect that wear was from the tread buckling due to the stiff side walls which probably reduced the amount of rubber on the ground. I found I could reduce that wear by running about 35 psi in the front. In the rear I would run 33 psi and I got even tire wear across the tread when doing that. On the street I ran the recommended 30psi all the way around. I ran well with the EMTs but not good. When I switched to Firestone Run Flats I was able to run faster in the rain with those tires than I could in the dry on the same course with the EMTs. R compound tires help a lot but they are hard to find in the C5 sizes. I ended up switching to 96 Grand Sport wheels with 315/35/17s all the way around and running in a modified class Vs stock.

The biggest problem I ran into with the C5 was the transmission ratios. It is just not geared well for a tight autocross. Low gear is too low and 2nd gear is too high. If you are in low gear you will have trouble coming off the corners due to the torque that Dave mentioned. Couple that with very old rubber and you can have an interesting day.

Bill

AU N EGL

Bad tire grip and tire spin has more to do with that sickness that start with all car racing, Leadus Rightus footus.

VetteDrmr

You can't trash what won't wear. Run 'em on the street until they die (probably around 75,000 miles or so ), and get a set of wagon wheels and either some decent street tires or the R888/RA-1s that were mentioned and use those for your autocross fixes.

HTH, and have a good one,
Mike

SaberD

these are new emts. the previous owner replaced them shortly before i bought my car in march. it was completely stock so im sure he had no intentions of racing it. i have them on wagons right now, but im getting some speedline z06 wheels with new tires. just thought i would keep the ol wagons for autocross.
my throttle control got a lot better after my first run where i figured out how much i could give it. i just wasnt very pleased with the fact that i couldnt barely give it any throttle :P. anyways next time ill drop the pressure to 28 and see if they do any better. btw i did keep it in first the whole time. its was a pretty slow track so top speed was probably about 30mph. i probably should have kept it in second. i am fully confident that it would have still smoked em in 2nd. then i would have had more precise throttle control too. oh well. live and learn.

napacruzerc5

Instead of taking it to the rev limit in 1st, I usually short shift to 2nd. Less torque out of the corners but still enough to spin the EMTs if too much gas.

c4cruiser

If the EMT's are new, why not keep them for street use and use the new Z06 wheels for some sticky tires like RA1's, R888, Nitto NT05, or even the Kumho ASX ?? Any of these will provide much more traction and are considered a "street tire" as opposed to a "race only" or "competition" tire. You can bolt them on, drive to the event and back, and you will have serious traction compared to the EMT's.

With only trying autocross for the first time, sticky tires should not really be your first priority. Seat time is the best way to figure out how the car handles and how you can improve as a driver. Once you improve your skills and understand how the car works, then you can move on to mods that are allowed in your class.

Before buying wheels and tires, check the rules carefully to make sure that the wheel and tire sizes you want will be legal for your class. If you go too big, you can wind up in some type of a modified class.

SaberD

you must be kidding right? those wagon wheels are horrible looking! anyways i agree with your statement about priority and i think the number 1 thing i need to learn right now is better car control. for that the emts will do their job. later on ill start tracking the sticky tires.