AutobahnRacer

My C5 was alot of fun, and really competitive until this year. I can't hold a corner to save my life . . . so what changed?

Last Friday the shop changed the front left wheel bearing and upper control arm/ball joint. I do think that was a problem, as the car is 'better', but not where it was.

I thought the wing may have been tipped in too much, as the prior two races were in the rain, and forgot to set it back for dry. That too helped, but I'm dancing through corners, over-slowing, trail-breaking forever just trying to keep the front end planted.

The only remaining BIG CHANGE is using the GrandAm Continental scrubs vs. a Hoosier Slick and/or other (Pirelli/Yokohama) slicks in all the past 4-years. Yep, I needed to save a buck, and went to the scrub tires at 1/4 the price of new. I know these tires have a stiffer side wall, are a harder compound, and last forever . . . but is PUSH a part of what I should expect or is there something else going on?

In yesterday's race at Autobahn CC I'm off last years pace by as much as 3-seconds. I qualified 2nd, found 1st in the first corner, but eventually gave it all up for a 3rd place finish. It's ALL due to the push, and slow corners.

YOUR POSITIVE FEEDBACK IS APPRECIATED.

Thanks,

AU N EGL

the Continental scrubs, Old Hoosier Slicks / VRLs or Pirelli / Yokohama slicks are endurance racing tires, not go fast tires.

Hoosier As are go fast tires.

Did you change BOTH front bearings? if not that may be part of the problem too.

Stiff side wall tires, or tires that take several laps to get heat into can cause push. Take longer to warm up and one can loose positions in a race with these tires.

If you want go fast tires, Hoosier As are the only tire for races. General Lapping and HPDEs the scurbs are great.

Good Luck

wallyman424

Well I mean theres not much to say here. Wheel bearing didn't change anything. The only thing that's different is the tires, you kind of hit the nail on the head already.

If you want to keep using the tires, you can tune the suspension around them. Otherwise just go back to hoosiers. All depends on what you're going to run for the rest of the season.

6SPEEDZ

You are going to have to change your set up for different tires. Are the scrubs your getting a known consistency? Are they the same brand, compound, size, NUMBER of HEAT CYCLES? You can start by changing tire pressures, stiffening the rear anti roll bar, change the rake of the car, damper settings if available and spring rates. What you do first depends on how bad and where it is pushing. The tires will not be fast on the first lap like a hoosier A6 and it will be worse the colder the track conditions are as far as the differential between the 2. Have you taken tire temps and pressures? we need more info.

mountainbiker2

It's the tires. When I have new A6's my car has a small push. When I'm ready to throw them away, my car has more oversteer. So who knows when buying used tires what your getting. I find at the end of the day, it's not worth buying used tires. A lot of our money is spent on just getting to the race, gas, entry fee, maintenance items, time and energy. Then waste the whole day on bad tires.

Steve A.

parkerracing

As others have said, and I agree, your going to have to tune the suspension around the tires. Some will be no brainer stuff but others will be trial and error until you find out what the tire likes./:\

Rob31

Yesterday was 40 -45 degrees out . Got a tire temp sheet ? Bet they didnt get much heat at all .Bet the track was slick for everyone .
Any new bumps this year ?

What turns had the new push ?

JDIllon

Sound like tires! in the end it all comes down the $$$ LOL! Sounds like you have 2 choices, go back to the old tires and set up or keep running the scrubs and see if you can get a setup that will work with them. My vote would be to go back to the Hoosiers and see if that is the problem!!! JD

AutobahnRacer

My old tire choice (2010) was a Hoosier race slick (not the A6 or R6), and Yokohama in 2009, Pirelli in 2008. I haven't run a DOT tire for a very long time. The tire change was purely a financial experiment, but 'point taken' on the other costs involved with running the car, and why forfeit the enjoyment factor on tires.

I'm going to try more camber and a sway bar adjustment, take temps on Thursday and see what happens. The only other definitive answer would be to run a new set of Hoosiers to see the difference.

Thanks for the commentary.

AU N EGL

the "DOT" tires are in NAME only. not really street legal tires.

the Hoosier Grand AM slicks are endurance tires. Great for lapping days, HPDEs or long wearing tires.

Fastest laps will be on Hooser "A"s

only tire that maybe faster are the Good Year G19s in the R375 compound.

AutobahnRacer

The Hoosiers I ran with were R80 and R100. Great tires, but a full race slick, and a heck of a lot stickier than the A's or R's.

UstaB-GS549

If you are running same tires at all 4 corners, I would think that grip would be reduced everywhere and the front to rear balance would be the same.

Rear bar disconnected?

kentz06

Don,

To reduce push in my car I softened the front sway bar and reduced the compression dampening while doing the opposite in the rear. Unfortunately the ultimate fix was fresh tires. With fresh Hoosier R6, Kuhmo V710 or Michelin slicks my car goes where it is pointed. As the tires go through multiple heat cycles the push incrementally returns.

Anyone know why the fronts seem to lose grip faster then the rears?

Dean

GT Racing Tires

Don,

The Conti's should have hot pressure of 27 plus you will need to play with shock setting to find what works best for you. With the cold temps everybody was likely having the same problem.

All of the Conti's we sell have ONE heat cycle and are in great condition. So the people knocking buying scrubs are saying they run NEW tires every time the go out on the track! I doubt it.

I ran the the Conti's for the first time on Saturday and hated them the first session but after a few calls and adjustments they felt great and are fast.

Any questions call me

L98Terror

FYI a R80 is not sticker than a A6, they last a little longer but that's about it. From what I've seen, read and heard. I've run a R80 and did not go faster than a A6

96CollectorSport

Don,

Just wondering but have you ever ran new A6's? The Conti's are basically a bias-ply version of the R6 (same compound from what I've heard - different sidewall) This is why they don't take a penalty in HP/wt in NASA like the R80/R100's.
We have never really liked running R6's because they give up grip way before the rubber is gone. The A6's keep on holding on until they cord. When a set of R6's is heat cycled out it feels like the car won't slow down as well and the car typically starts to slide around a lot more.
I know the Conti's from GT wouldn't have been heat cycled out when you got them. But if you ran them for the NASA weekend plus some practice sessions they may be on there way out. I would say that we only get 6-8 heat cycles out of a R6 before they are done gripping - we could run them for 2 more weekends if we wanted to use up the rubber but the grip is no longer there.
Tires are the only thing touching the track and everything starts with them.
Joel

longdaddy

just a guess, but assuming that the car is balanced mid-corner and has 50/50 (or close to it) weight distribution, braking puts more heat into the tires than accelerating.

geerookie

Are you sure about this? I've been running these for 2 years and as far as I know they are a radial tire. When they were branded Koni I cut one in half and it was a radial tire.

95jersey

I think tires too! My car is 100% set up for Hoosiers with -3.0 camber. Once or twice I have tried running with street tires and with all the camber, the car pushes as you say, "like a pig". I notice if I were to ever run street tires, I would have to change my set up significantly and probably reduce camber and toe. It seems I am not generating enough grip with street tires (or treaded r compounds) to take advantage of all the camber. The set up with the Hoosiers only seems to work with the Hoosiers.

AutobahnRacer

Well, that's the beauty of a forum, we all have opinions, and what a great place to share. To say 'definitively' that something is so, I think the position is no longer about opinion, but fact.

In my opinion, the R80 up front, and R100 in back, when compared to a Pirelli and/or Yokohama SLICK, were 'similar'. When I ran the Hoosier R6, and 'graduated' to the Pirelli a few years back, I picked up about 2-seconds/lap. I also had to change suspension settings, and the increase in grip provided for substantially better cornering.

Your experience is substantially different than mine, and now that I'm testing a 'single heat cycle' Conti tire, I'm having a different experience. It's likely that the car will improve with suspension adjustments, but not likely to MIRROR any of the (3) slick options I've run in the past. It's a different tire, developed for a different series.

Saving $ 8000 this year sounded like I might be willing to go slower, and I'm still convinced that given there is no money coming back to me, the savings vs. performance is acceptable.

The purpose of my thread was to get help in determining what else I should be looking for.