IS300Turbo

What tire size and offset do I need for 17x7 wheels on an xA. Are spacers needed?

I know 205/40/17s work best, but people seemed split about using 215/45/17s cause some people have had them rub. Also, how big of a problem is offset (i'm assuming bolt pattern is 4x114.3)?

Tamago

bolt pattern 4X100
offset 38-45?MM

i run 215 45 17 and only rub in a hard left on a 2.5 drop. you can run 205 45's with ease..

if you run 40 series you're overworking your engine.. too much RPM on the highway.

manejounxa

I am running 205/40/17 does this mean that I am overworking my engine.what tire
do you suggest I should think about changing them too.............

IS300Turbo

Thanks for your help. So 205/45/17s are good. I want this to be as stock as possible so I don't have to start monkeying around with spacers and crap.

Tamago

yes, 205 width and 45 series on a 17 gets you as close to stock diameter as you can get.. 215 is closer but you get rubbing at low speed turns

psalonis

I suggest checking out the spec sheets on the tires that you're considering.

On my xA, I have Drag wheels 17X7 with +40 offset, Goldline springs and TRD shocks/struts. I then added rear hub shims from onetongarage.com
The tire I chose was TOYO Proxes 4 215/40-17
This tire is just 0.2 inches taller (at 23.9") than the stock tires. (stock 23.7" OD)
The 205/40-17 measures in at 23.5".

My aim was to remain as close to the stock OD as possible to minimize speedo error while at the same time trying not to affect RPMs at a given speed.

I chose the 0.2 inch LARGER than stock tire in order to (if at all) bring it done a couple of revs. -it's not noticeable seat of the pants.

With this set-up I have no rubbing problems whatsoever....Ideally I'd suspect that a +35 offset or so would look better (for 7" wide wheels), but the deal on the Drags was too good to pass up.

Keep in mind that most inexpensive aftermarket wheels together with wider rubber will add a few unsprung pounds to the car and maybe some rolling resistance. The Xa has less pep off the line and has lost about 2-4 MPG as a result.

The tremendous improvement in handling is worth it to me though.

Check out this handy tire size calculator....http://www.miata.net/garage/tirecalc.html
use it to get close and then check the spec. sheets on your favorite tires.

IS300Turbo

Why do you need the rear hub shims? Was that to compensate for cam/cast of the struts? The car only has the TRD lowering springs so I's assume I wouldn't need that much adjustment, it's not like it's dropped 2 inches.

Tamago

you don't need spacers. they improve handling/ looks, but not necessary

psalonis

I didn't need them, it was purely for the appearance.....the rear wheels appear to be tucked too far under the wheel wells without them. Instead of getting different offset wheels for the backs vs. the fronts, thus elimating any opportunity to rotate tires, I just put on the 10mm shims.

It improves the look IMO by widening the wheel track and making the wheels closer to flush with the wells.