Autocross wheels?
 

Does anyone run 18x9.5 +40 on all 4 sides in autocross? I'm assuming the grip is greatly increased but holding a drift is difficult because of the stock power. Anyone has this experience?

Why would you want to hold a drift at auto-x?

If you stay in stock class, you have to keep 17x7. If you go to STX, most people are running 17x9.

If you're drifting at autocross you're doing it wrong...

Well I'll be using that set up as a dd as well that's why, and there a twisty hills on the way to work =))))))

Unless you are going after trophies run whatever wheels you want. And you won't be competitive with those wheels in correct classing without forced induction anyway so just go have fun. Or read the rule book and build your car to the class if you want to compete.

And grip has a lot to do with tire choice as well. Autox competitive tires will have way more grip with large sizes (ie 200TW or R-Comps). If you run Nankangs probably not so much.

That still doesn't explain the drifting?

Very unlikely. As noted, the only class in which they're legal would require a lot of other work (and probably a car approaching the point you won't drive it to work.)

Square is where you want to be still. Sizes bleed by summertime else.

Drifting on the way to work? I'd be reconsidering priorities, but that's me. Insurance rates are already getting bad on this car because of such things... Save it for a sanctioned event. Sticky tires are more fun on the commute too...

You don't want tires that can hold a drift for autocross lol. You want tires that prevent drifting!

Street drifting... another way to create a part out thread.

But, in all seriousness.... Do you want to compete to win, or just auto-x for fun? If for compition, those wheels won't work for you.

When my insurance goes up I'll know who to blame.

I'll take a swing at it.

It will be rare for someone to autocross on that size as the larger diameter wheel adds unnecessary weight and the width is too wide for most classes that aren't unlimited so you're not going to get a lot of support.

Size of the wheel and tire and correlation to level of grip is weak at best. Going to a wider tire will add grip, yes, but not nearly as much grip as choosing the best tire for your application.

Compound > size

You could also put small 225 tires on those 9.5" rims going for hellaflush rubber band look, that won't grip as well as a tire that's more appropriately sized for the wheel (I'd guess about 255 is what you'd end up looking for). The added weight of the 18" wheels will also detrimentally affect handling as you've added unsprung mass forcing the suspension to work harder and making it less effective in the process. (You COULD spend enough money on wheels that they'll be as light as stock or lighter, but then you COULD spend that same money getting a more common size and be even lighter). You're also reducing the size of the tire, going more towards that rubber band look means the tire will flex less and you'll experience a harsher ride (along with the detriments of the added weight).

Will you still have a lot of fun on those wheels? Probably. IMO spend about 10 hours googling and reading about tire selection, buy tires that strike the balance you're looking for and call it a day.

Also don't forget that 9.5" wide wheels are kind of pushing it for fitting on an 86, do some research (not posting simple questions) over in the wheels and tires section.

Edit: As mentioned above most people are running 17x7 or 17x9 to fit within the two most common classes the 86 falls in. FWIW If I wasn't competitive and just wanted an all purpose fun car I'd probably be looking at a 17x8"-8.5" wheel which is lighter than stock with a ~235 wide 200+TW tire that is very close to OE diameter.

As for the grip vs. drift balance of adding that much rubber, the hardcore AutoX guys could certainly mount a 255 sized tire and are allowed to go up to 265, their cars are definitely tuned for more power than stock with a header but most are running 245. I've heard that this car is too light and not enough power to get 255 sized tires up to temperature and working well, but I only heard that from a guy who heard it from a guy so I don't know how true that actually is yet.

[ame="https://www.youtube.com/watch?v=dlJJiB9guoE"]Top gear funny #1 low profile tires - YouTube[/ame]

Some repeating info, but...

Not competitively, they don't. Second, have you proven that to fit? There isn't that much inboard room, and 245/40-17 on 17 x 7 +42s rub a little on the inside on my car. Adding another inch and a quarter of wheel may flat not fit, at least not without spacers and new studs.

Like everyone else, if you're actually drifting, you're not going fast in autocross. That said, a lively rear end is reasonably doable on stock power, and a small amount of that is actually beneficial. But, that amount is called getting the car to rotate, not drifting. I had to dial a fair amount of pendulum-ish behavior out of my car. Pretty sure most of us did.

If you're talking about drifting on public roads....You'll shoot your eye out, kid. :D

My car must be broken, I've only gotten full blown oversteer once when I had a really biased alignment, by the next run I had adjusted it back to being fairly neutral.