Quote:
Originally Posted by rory_a
Any issues fitting the 15x9s with the stock-style strut/spring combo?
I'm 99% after a complete visual conversion on this car - wheel/tire combo, probably coils to get it low enough, etc. Basically plan to keep it always for sale, so going after mass-attraction rather than autocross or track performance. Will be driving it, showing it, flipping it.
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15x9+36 with 225 width RA1's is what I'm running at the track. 15x8+20 with 205 StarSpecs is my street setup.
Jump to 9:00 to see the tire clearance:
I rolled my fenders for the track tires... didn't need much, and I'm running maybe an inch lower than stock. You might be able to get away with just taking out the fender liners and bending back the one mounting tab on each side if you're at stock ride height and not running huge width tires. Hell, at stock height, you might not rub at all.
On the shock side of things, I don't know how much clearance there is. You might want to stick to a lower offset 15x8 instead of a 9" wide wheel if you're staying with stock springs. They look just about as wide, and you won't rub the shock. But again, I don't know how much clearance is an issue with the stock springs, since I took them off right away. It could be a total non-issue if there's like 3" of clearance back there or something, I have no idea.
Here's what my 15x8+20's look like:
For reference, the original wheels on the car when I bought it were 15x7.5+42 with 205 StarSpecs. So you can use that as a starting point for back side clearance calculations, if you go 1.5" wider, you need to go like -20mm on the offset to keep the same backspacing, so a 15x9+22 will clear the shocks for sure... but that's 14mm more fender clearance to worry about than the +36mm wheels I'm running.
One more thing to consider: anything over about a 205 width tire on a stock-power Miata actually starts reducing top-speed.
At autocross, it doesn't matter much, because you want all the low-speed grip you can possibly get, but at the track on the straights, or when considering fuel mileage on the highway, big wide tires on a Miata can be counterproductive. Just food for thought.
Finally, on those Koni yellows, there are 3 spring perch positions. The highest perch is the same as stock, which is required to be stock legal in autocross. But you can lower the car like 1.5" on this setup if you just want to be lower, though a slightly shorter bumpstop would be recommended. FCM makes a 36mm bumpstop specifically for this.