I'm in need of input for two questions.
1. What tire size for my 17" rpf1s? Still deciding on tire, but likely switching from star specs to re71r
2. Alignment values for my fa coils with 12/12 spring rate? Including height suggestions.

Car is mostly track use only, does get driven to some events and for ****s and giggles on the weekend. Auto x is the majority of racing, but I'm also doing road course this year. 24mm rear sway, solid mounts all around including diff, moustache bar delete, I believe that's the list so far on suspension. I will roll the rear fender and front has wider fenders to fit about anything.

 

How wide are your wheels?

And you should think about have the rear of your car 2k stuff than the front. So lower the front springs to 10k, or raise the rear to 14k.

Alignment will dependent on the type of tire being used.

 

Why make a change to the stiffness? Curious.
I'll double check the rim when I get home. I think I believe I got the 8.5 wide rim.

 

Because the Evo tends to push with same spring rates front and rear. You want the rear about 20%-25% stiffer than the front.

 

Not a big fan of the 8.5" wide wheel (9" or wider) but a solid 255/40 would look & perform well

Regarding your current rates, due to the motion ratio of the rear susp, the EVO needs a higher rate rear spring vs the front. But, I have learned that some of that 12K rate can be tuned-up by running an uprated RSB (24mm min) & adjust the setting to the firm

This may give your susp a bit more neutral feel but will still be under steer prone

Either way, the 12K/12K is not a serious negative. If you were going to lower one of the rates, reduce the front to 10K

 

Confirmed they are 8.5 wide. Thanks for the input. I'll get 10 for the front. Any suggestion on tire? I was guessing 255/40 so thanks for the confirmation.

 

Dont get me wrong about the 8.5 wide thing. That will work OK, but the real performance benefits start w/the 9 & above for our EvO

And dont worry too much about the spring. Set your 24mm bar on the firm set & try it & see what you think. If you feel neutral & can get the back end around you might be OK. The EVO is so understeer prone that a 10K/12K setup might be better down the road

As far as tire, too many choices. If its just for AutoX & some light track work you might want just a good summer tire like an Nitto NT05

 

We can't properly answer your question without knowing your goals for the car. If auto-x is your sport then you need to pick a class. Actually, you don't have to, but picking one now could save you a ton of money over the long run. Buy wheels and tires (RE-71Rs) to match what class you want to be in. If you want to build a well rounded street/auto-x/track/play car then the options are limitless. Whichever way you choose you will probably not be happy with the 8.5" wheel width you're about to put on your car. Regarding springs, +2k rear is the standard for our car due to motion ratio. I also run 12k square along with the rest of the mods in my signature. I run the rear bar on medium-hard and run on the mid-high end of my AST's rebound settings (1-way adjustment).

 

With the mods that came with the car I have to be in SM. I know I'm not overly competitive with my current setup, but I'm working with what I got right now. So 255/40 re71r and all stiff on the rear sway. I'll see what happens and possibly get the new front springs if I have turning issues. I'm limited in the rest of my purchases for the year so yeah.