Corvette Z06 Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
168 Posts
Discussion Starter #1
looking at a rain setup for the car, any thoughts from Dave P., Brad, or anyone else on a setup. 17x11 w/315's on all 4 corners or 9.5 w/275 up front. Also, suggestions on rubber ( besides the hoosier rains ). Any guidance would be appreciated, I'd like to be within a stick throw of you guys when i get out there! :cheers:

Joe
 

·
Registered
Joined
·
2,170 Posts
Joe,

Consider the value of this advice, as it comes from me (not very valuable!):

I have run Goodyear rain GS CS 315s on all four corners. I have been told to use the 275/315 set up, as the smaller front tire is less prone to hydroplaning. The narrow front wheels don't seem to allow the tire patch to "flatten" out all the way with a 315 tire.

Tire pressures? 29 front 25 rear.

My experience with the Goodyears? My first session in a National race was at Summit Point in April 2004: results were I had the pole. At the same track one year later I repeated the results, this time in front of 4 AWD T2 cars. At Nelson Ledges this year Freddy Baker and I swapped the pole position three times until he finally finished on top.
 

·
Registered
Joined
·
5,491 Posts
I recommend 275/315 as the narrower front tires tend not to hydroplane as much.

In addition, to increase traction on rain tires I recommend INCREASING the pressures. This tends to "push" the water out from under the tread and helps the water channel better.
I run my rain tires at 36/34 psi.

I recommend GY ZRS "S" rain tires. These are a softer S compound and are based on an F1 rain tire tread pattern. These are used in WC.

The new Hoosiers are a very good rain tire.

If you are running adjustable shocks the Bump should be set at the softest or near softest setting. Rebound need not change.

Adjustable swaybar end links should be set at the shortest (NO preload) setting length. Some elect to dissconnect the swaybars completely.

TC/AH ON or Comp. Mode is advised in the wet.

It is critical that throttle, brake and steering inputs be gradual and smooth. Almost deliberate and deftly slow(er).

If the track starts to dry, rain tire compounds and treads can sometimes in fact be stickier than slicks on dry pavement. This is due to the heat build up. You can "dry" the tires and heat them up causing them to increase their adhesion by running the dry line just prior to corner entry but you must cool them by running a wet line out of the corner. Otherwise they will start to overheat, chunk the tread and possibly blister and seperate the carcuss. When the tread starts to "wobble" and starts to get "squiggly" it is time to change back to drys.

The line for wets are different than drys. I tend to apex very late. This allows greater speed on the straight aways with longer braking zones
 

·
Registered
Joined
·
350 Posts
I run the Kumho Victoracer (full tread). It's the best intermediate tire out there, but if it's a swamp, then the GYs or Hoosiers are probably a bit better. If it's just a damp track (and/or drying), the Victors will be the tire! I run 275s up front in the rain, but the verdict is still out on pressures. I think I've got mine set to about 30 all around.

If you raise the pressures, the blocks will open up more and push more water out, but when you do that, you make the sidewalls stiffer. If you reduce the pressure, you soften the tires (and therefore the suspension) and you are able to generate more heat in the tires. In other words, try several different pressures out there and see which one works best for you and your car.

And OBTW, Mid Ohio is a zoo in the rain. If you've never driven there when it's wet, it's a god-awful experience because of all the different track surfaces. And man, is it slick!

Good luck!!
 

·
Registered
Joined
·
5,563 Posts
Joe,
David, DJ and Chris have well covered the topic above, but I'll add my 2 cents just to give you more to ponder.

I've only run one rain race and ran that on my stock wheels/tires. The race was in extremely heavy rain. In the dry, I had qualified well in front with T1, T2, AS and some others and won the Regional with the same guys on Saturday in the dry. In the wet on the stock tires, an AS car on Hoosier rains walked away from me. The stock F1s just couldn't channel enough water and they weren't as sticky in the wet as the Hoosier rains (which weren't DOT legal at the time). At that point (July 03), based primarily on Heinricy lapping the T1 Runoffs field in 01 in the rain on Goodyear GS-CS Eagle Rain tire, I broke down and bought a set of the Goodyears. At $400 for the fronts, and $460 for the rears, this was a significant dent in my budget. Having spent nearly two grand on rain tires, I thus ensured I would not race in the rain again... :lol:
Two years later and the tires are still sitting unused, with not one lap to their name, and essentially useless as I'm sure the rubber is not up to standards anymore.
I did qualify in damp conditions twice. Damp conditions (wet, but with no standing water) present their own challenges. A wet tire will overheat and breakdown as DJ mentioned above. A slick is better, but scary. An intermediate, like the Victoracer is best is this situation. Given that I was financially challenged, I only had two sets of wheels, which made tire choices problematical. I usually went to a race with a new set of drys and a used set of drys mounted, and my rains unmounted. A typical Midwest Division weekend was Regional qual Sat morning, Regional Sat afternoon, Nat qual Sun morning and Nat race Sun afternoon. I would usually put one heat cycle on the new tires during Regional Qual, run the old set in the Regional, use the new set for Nat Qual and race. Wet conditions always threw a huge monkey wrench in that plan as I'd have to scramble to decide which set of tires to dismount, run to one of the tire dealers at the track, and have the tires dismounted and mounted in time for the practice/qual/race. Hassle. I really needed a third set of wheels. As a result, in both cases of damp qualifying, I happened to be at my home track in Memphis. In both cases, I ran home and grabbed my stock wheels out of my garage, threw them on (now with Kumho Ecsta MX mounted) and qualified poorly to the guys on full tread depth Kumho Victoracers, or even the brave who went out on slicks.

If I had the money, and wasn't on a tire deal (I'm not), I would get a set of 275/315 Goodyear DOT Radial Eagle "S" Rains or the new Hoosier DOT Rain Radial, along with a set of intermediate tires like full tread depth Kumho Victoracers along with enough sets of wheels to support these.

I too favor the 275 front and 315 rear in the rain for the reasons mentioned above. I don't have enough experience in the rain to give you a good tire pressure recommendation. I've heard both points of view mentioned above. In my opinion, I would tend toward lower (e.g. normal) pressure for a race rain tire as it is designed to channel tons of water already and doesn't need to crown (as DJ mentions with higher tire pressures) as much as a normal street tire.

Also as mentioned above, the rain line is much different from the dry line. The dry line is normally more polished and oil covered and provides poor grip in the rain. Running off the dry line in the rain provides more grip. If it rains, I suggest talking to some of the Mid-Ohio veterans about the local rain line, or try to line up behind one for the practice/qual session and follow them.

Good luck and have fun out there. I'm jealous!
:cheers:
 

·
Registered
Joined
·
168 Posts
Discussion Starter #6
Thanks for all the input guys! I have decided to run the 275/315 setup on 9.5's and 11's. I also decided to run the Kuhmo 700's, as an intermediate seems my best bet for all around. I'll just have to run in someones tracks in really heavy rain!! :cool:
 
1 - 6 of 6 Posts
Top