I'm currently running 18x10 +45 with a 285/35 tire in the rear. I know this is too tall and also extremely heavy, I can feel the sluggish acceleration. I'm switching to 18x9.5 +38 and looking at either a 285/30 or 265/35. I know the 285 is closest to stock, but will I feel a big difference in acceleration between the two? Also is a 285 too big for a 9.5 in wheel? My setup now is just too tall and heavy and feels much slower than it should be.

 

285 is fine on a 9.5wheel. Id run the 285 on a light 9.5" wheel before a heavy 10" wheel. What kind of tires and what do you use the car for?

 

Hopefully more auto-x/track time in the future. In the 285 I was looking at the Sumitomo HTR Z III. Not many choices. I'm currently running Nitto 555's.

 

In that case id run a 265/35 Dunlop star spec, Kumho XS, or Hankook RS3. The better compound of those tires will give you MUCH more grip than the wider sumitomo.

Dunlop wears really well and stays grippy
Kumho is makes more girp when new but wears quicker
Hankook is supposed to be better than both but I dont personally know anyone running it yet.

 

I used to sell Sumitomo tires HTRZ-series tires...they were junk. I wouldn't recommend them.

 

Plus 1 on Dunlop Direzzas. They are quite the light weight tire (27lbs at 265/35/18) and have performed well for me.

 

[QUOTE=fd_neal;10547750]In that case id run a 265/35 Dunlop star spec, Kumho XS, or Hankook RS3. The better compound of those tires will give you MUCH more grip than the wider sumitomo.
QUOTE]

+1

I would also consider Toyo R1R...

I would run the 265/35 in the rear as it has more sidewall (more off the line traction) and is going to be taller than the fronts. the 285/30 is an excellent tire for the front of an FD but is too short for a staggered rear set up. Your car will look funny with the front sitting higher than the rear.

If you step up to a 10 inch wheel I would run a 295/30 18. Wider...taller...more grip than the 285.

 

R1R's are too soft for heavier cars. they're only successful in autox on light cars because they overheat too quickly with more weight/power. they also wear extremely fast. cant recommend these to anyone other than miata/civic guys

 

What wheels are you running? My 18x10 Fikse Profil 13 weighed in at 20# and the 285/30 Yoko AD07 weighed in at 26#. I'd recommend something similar in terms of tire sizing, and if it's in the budget grab the AD08 and you won't look back

 

My new wheels are Gram Lights 57F; 18x9.5 +38 Rear, 18x8.5 +45 front. I want something that's grippy and light weight but that's closest to stock. The may reason I'm debating the two sizes is the diameter. Will I notice that big of a difference in acceleration between the two?

 

18x10 +45 with a 285/30-18 while heavier than a smaller wheel (obviously) is really a perfect fit for the rear. A 283/35 is definitely too tall. More than anything the taller wheel is what is making it feel sluggish. Just like running a different rear. IE 4.1 to 3.9. Which is fine if you are running a v8 but not so hot for the rotary.