wheel advice needed~?
 

several questions after reading a lot of guides/ watching videos on wheel fitment.
my goal: to run 245/40s on my 2017 86.
from the start i wanted to run 17" wheels but I noticed a lot of people are running 18s. So is there a reason to why they choose 18s over 17?
and how wide would a 17 need to be to safetly fit a 245/40 without rubbing or having body issues.

Go to the wheel and tire fitment calculator. Plug in the info you want then shop around for wheels and tires.
You could also read a ton of pages of other people's offsets and specs.
The key is getting the right wheel offset.

As for 18's people just get them for looks only. Zero advantage. Depends on the type of wheel, 18's add more wight.

Rubbing issues would depend on the offset of the wheels and how low your car is, as well as how much camber you're running as well as spring rates. I'm running 245/40/17 on 17x9, ET35 (iirc) on fairly low ride height. My front camber is past -2* (can't remember the actual spec), and the rear left is within OEM spec (right side could not be adjusted anymore to get within OEM spec). I don't really rub unless is a bigger freeway dip.


https://scontent-sjc3-1.xx.fbcdn.net...8d&oe=5C8C30ED


18's, imo, are for aesthetic reasons and to possibly have more options in terms of width and offset combinations.

Alright thanks for the replies! i'll just run a 17x8 or maybe even 17x8.5 with a 38 offset.

Konig has quite a few flow formed wheels in 17x9 +40 offset which should be the sweet spot for these cars.

To answer your question, I have a few other questions:

Is there a particular reason you want to run 245 wide tires? Are you going to run boost, autoslalom or track? If not, then you should consider 225s because you will have fewer rubbing issues and they cost less and be no less effective as long as they are of a decent compound.

Have you looked at exactly which tire you want to run? A Hankook RS4 245 is wider than a Michilin PS4 245 and that may affect what will fit. Of course, I think this ties into the first question.

Have you done anything to your suspension? If not, do you plan to? Running coilovers gives you a lot more room inside the wheel well and having camber adjustment will also affect how things fit.

For and extream example, I put 12k miles on and autocrossed 245/40r17 Dunlop Z2 Star Specs on stock 17x7 +48 wheels in SCCA C-street a couple years back, no rubbing or safety issues just poor side wall feel under hard transitions. 225/45r17 would have been a better size, for a tighter side wall.

I have 18s now but would probably go 17x9 +35 if I did it over again.

I have 18's for looks. 18x9 +30 245/35 square. (my rear is +27)


17x9 is what I would suggest for 245/40/17 tires. Also, if you have lowering springs, you will want +30 to +38 offset. If you have coils, you can get +38 to +48 offset. Camber bolts will tuck the top of your tire with a 245. (even at +30 in front with a 1" drop; the rear will be approx. -2 natural camber with a 1" drop)

18 in. wheels can be had as light as 15 1/2 lbs. but most are heavier than 17's.

18's result in less sidewall flex and "bump softening", and easier large brake kit fitment. (I run 6 piston).
:cheers:

18's for the style -- especially the 18X9.5 for the concave style look. Some people run it to clear BBKs (like me).

For 245, you can run 17X9 which is a pretty popular size. Note, 17 inch tires are cheaper than 18s.

What's the point of the 245? Like, it doesn't seem like a good goal.

The point? For me: Better looks and more grip. Additionally, most wheels that are really concave are 9" or wider. And a 245 fits nicely on them. Also 245/40/17 and 245/35/18 are stock diameter tires; making them a good choice for people that want wider tires.

I know some reasons why that tire would be the choice. It's just hard to provide input when that size isn't really the goal (it shouldn't be anyways). Looks? Probably tell the guy to get 18s. Performance? Maybe stick with a 225 unless you're worried about BBK clearance. That's all I'm getting at.