With wheel/tire specs please.
I am most interested in those 18x10 square with 285/30/18 tires.

Things I would like to know-
What offsets did you use
Are you using spacers on rear
Assuming everyone is using coilovers and after market trailing arms
Did you encounter any rubbing? Where? Just on street or on track too?
Did you end up rolling fenders? Modifying fender liner? If so how?

I remember a few original members running this set up i.e. Max Cooper.
Lets see what you have..
Legit track setups only please.. No stretched tires or wide body cars.

Thanks.

 

My current (pictured) set up is this 18x10.5 +38 with 265/35-18 all around.
coilovers
Front camber maxed and front fender lips rolled under.
Rear camber ~1.2 and stock rear fenders and stock rear trailing arms.

I have 295/30-18 sitting in my living room for my upcoming 18x11 +45 wheels. This will have the outer wheel lip exactly in the same spot as current pictured set up, but go in as far in the rear as you can on stock trailing arm.

I will have to roll the rear fender and/or run more camber as there will be less sidewall stretch, but 285s would be perfect fit.

 

This fitment calculator link shows the pictured 18x10.5 +38 265/35-18 combo and what the 18x11 +45 285/30-18 combo would be. As you can see the outer (fender) fitment would be exactly the same and it will fit with coilovers and stock trailing arm (with low/zero rear toe in).

Online Wheel & Tyre Fitment calculator. Offset, Tyre stretch and Rolling Radius calculator

 

I have 18x11 on back but its more of a "Stance" set up. Fenders are already rolled but I want a square set for the track, no stretch this time.

Thanks for the reply.

 

For most 285/30-18 track tires 18x11 is not stretch, but rather recommended fitment.

Hoosier R6
BFGoodrich g-Force R1
Michelin Pilot Sport Cup

Sorry, you didn't specify what tire you were running.

 

If you are going for a certain pudgy tire look over max performance the offset would remain the same +45.

Offset fits the tire to the chassis/fenders.

Here is your proposed 285 on a 10" wide rim with the ideal +45 offset compared to the photos of the fitment I posted above.

Online Wheel & Tyre Fitment calculator. Offset, Tyre stretch and Rolling Radius calculator

 

Its the offsets.
Running this right now
Work Meister S1R Bright Buff O-Disk 18x9.5+20F, 18x11+25R
Tires are 235 40 18 and 275 35 18
Its not an ideal track fitment.

 

red fd looks awsome

 

18x11 +45 295/30-18 square fitment.

Don't be afraid to go big up front.



Coilovers, fender lips rolled under front and rear, shortened sway bar tube, -2.4 deg front and -1.2 deg rear camber. Autocross car

 

I decided on Work S1R 18x10 +50 with 285/30/18 tires. I will post pics when they arrive and are mounted.

 

Those 295s must rub on the inside plastic at full lock

 

I don't believe so.

The Z221 are narrow 295s like R888 and not fat 295 like Hoosier A6.

I will take a look at the fender liners.

 

The tire doesn't hit the fender liner at full lock static or turning around slowly.

There are clean spots at less than full lock on the fender liner from tire contact after autocross though.

The tire contacts the liner over large bumps when turning- our autocross lot is really torn up.

 

if your tires don't hit the fender liner, you're tires aren't big enough

 

wider tires doesn't equate to better handling/grip in every case. You must also match your tire width to your wheel width. especially when it comes to the front tires.

Check out slide 34 on this presentation about wheel/tire width and what you should do.

www.cb-racing.com/PilotCup_​Presentation.PPT

 

wider tires doesn't equate to better handling/grip in every case. You must also match your tire width to your wheel width. especially when it comes to the front tires.


Tire manufacturers don't make the consumer race tires we buy for specific vehicles.

The FD RX-7 has very favorable camber gain/body roll curve compared to other chassis paired with a low center of gravity for manageable body roll.

FD RX-7 racers will have found that even with low profile wide tires you are struggling to use the rounded section of the tire where the tread cap meats the sidewall when running the correct negative camber

By using the widest wheel recommended by the manufacturer you are pulling the tread surface more flat at the junction of the tread cap and sidewall.

This will allow you to put more of a given tires tread width on the ground and have fast translation times between inputs and tire response.

There is definitely more than one way to skin a cat though.
Some racers will run lower pressures to spread the tire contact patch to the ground and lots of negative camber to to compensate for the sidewall deflection. This will slow the tire response and you have to plan way ahead with your inputs.


Additionally, I have found a chassis with strut front end like my FC RX-7 (or Porsche, BMW, Evo etc etc) will often benefit from a relatively taller front sidewall and a tire with a more rounded tread surface.

This will compensate for the wide variations of bodyroll/camber needed in cornering and it will also improve braking considerably as the taller sidewall will allow more tire contact with the large amounts of static negative camber required.

 

A few days late on the thread but I've ran 18x10 CCW Classics with the standard FD backspacing(7.5 I believe) on several different FD's without issue. Anything from 275 Starspecs to 285 R6's. No fender rolling, stock trailing arms... no rubbing.

Silver FD with 275 star specs in some pictures, 285 Hoosier's in others. Stock trailing arms, no fender rolling. I think I have Tein Flex's on the car in all of these pictures






Same with the yellow car before I put the 18x11F and 18x12R. I did have aftermarket trailing arms, which do slightly rub ever so much.