Tire combo for autox question

[Chill2008]

Since I am too cheap to buy a full set of lighweight wheels and hoosier r6/a6 tires, does anyone have experience with a FWD car running Rcompounds on front and street tires on back? (my specific set up would be 245 fronts and 225 rears)

Regaurdless of if you have or haven't, would it be a significant (if any) benefit over running all street tires?

[Theodore]

(12-01-2010 05:09 PM)Chill2008 Wrote:  Since I am too cheap to buy a full set of lighweight wheels and hoosier r6/a6 tires, does anyone have experience with a FWD car running Rcompounds on front and street tires on back? (my specific set up would be 245 fronts and 225 rears)

Regaurdless of if you have or haven't, would it be a significant (if any) benefit over running all street tires?

Strange enough ...Per Olof is doing that on his nationally competitive Mini. But ... it came about through a lot of experimentation and he only uses that set up on certain courses. The key is finding the balance. Too much weight or too much stick on front, rear comes around.... too much on rear and it pushes the front out. You add a splitter on the front, you better dial it in with a wing on the back... everything seems to have an equal and opposite reaction...

I'd borrow some and take it for a spin and see how it feels. It might take some tweaking with a pyrometer but it's possible that could achieve a balance that would work for you. It would also be nice to only have to haul and change two wheels at events!

Better solution.... maybe? Give me a tire size and see if I can get some used but in decent shape. Then you have 4 matched Hoosier R comps and have a better base line for suspension tuning and tire pressure tuning. nothing much happening until late winter early spring on AXs so I have time to find something...

Just a thought.

[Coolant]

Dont know about mixing r comps with street tires, but I used to run super grippy summer 275s up front with 255 allseasons out back. Wasnt the fastest setup, but I learned tons about dealing with oversteer! If you're looking to up the star specs you have i wouldnt mess with r6s unless you run some really long courses or short run groups. They apparently take a while to get up to temp.

[wrc_fan]

I haven't heard of anyone doing a stagered set-up mixing race rubber and street, just different sizes for r-comps. It's been proven in FSP at SCCA nationals that either route will perform well. FYI at nationals, the 4th place rookie driver had a square setup with 18's on an '04 Mazda 3. Other random thoughts on this:

-2nd hand, I've heard that D Stock Integra drivers run 275 fronts with whatever throw away 225 rears they can find
-Seems like your proposed setup will be good for braking, acceleration, and sharp cornering, but be limited in sweepers and steady state stuff
-Camber challenged front struts will eat up the outside edge really fast on the race tires (you'll be flipping tires a lot)

I have a friend in michigan that runs used R6's on stock wheels on his MS3 in D stock, essentially he gets the same effect (as rear streets) since the R6 never really gets fully to temp in the rear. This could be a good option, as you can get used R6's for a reasonable price.

FWIW, I've ran 20+ events on kuhmo V710's that get rotated every event on my car.

[dave99rt]

(12-01-2010 05:09 PM)Chill2008 Wrote:  Since I am too cheap to buy a full set of lighweight wheels and hoosier r6/a6 tires, does anyone have experience with a FWD car running Rcompounds on front and street tires on back? (my specific set up would be 245 fronts and 225 rears)

Regaurdless of if you have or haven't, would it be a significant (if any) benefit over running all street tires?

i've run this setup before in the past when i was down to 2 good race tires.
you need to use sticky street tires in the rear.

it's probably best to run them a little on the low side for air pressures and drag them to get them up to temp quicker.

you'll always have better response and increased lateral grip with race tires.
some of the new street tires are quite sticky though, but no hoosier in the end.

i think running a staggered setup will cause issues on medium to high speed sweepers and transitions, i'd probably recommend running the same listed tire sizes to minimize the grip difference.
realize Hoosiers in 225's are around .7-.8" wider than a street tire 225.

if we keep racing in that little terd lot on campus, it probably won't matter, the speeds are too low.
if we get a bigger lot, or race in Anderson, then it will matter.

if you have a stock rear swaybar, you'll probably be okay.
bigger rear sway? have fun!