Max size that will fit in stock fenders without a fender roll is 235/40/17 using our Advanti Racing, Konig HyperGram, and 6UL Racing Wheels in either 17x8 or 17x9, as long as you have about 1.5 degrees of negative camber or more and a 45mm offset wheel. For street use we strongly suggest 8 inches as max wheel width, when used with 235/40/17 tire that gives some curb rash protection and comfort with a big increase in grip compared to stock. If the car is lowered and/or raced, this size may slightly rub the plastic fender liners inside the wheel well at full steering lock and/or over big bumps/dips in turns depending on alignment settings, particular brand/model of tire choice, etc (same story with taller 225/45/17). In our opinion 9 inch wheels on this car are just for the customers actually racing the weekends at autocross and track events, driving 9 inch wheels on the street is just asking for curb rash and rough ride for grip levels you cannot really use when not at SCCA and track events. Typical STR autocross setup is 17x9 with 245/40/17, which can be used by SCCA STR competitors with a fender roll.
WEIGHT: ADD LIGHTNESS!
The Mazda MX5 Miata is very sensitive to what is called unsprung weight (which can best be understood as what hangs off the Miata suspension rather than what sits on it). We therefore strongly recommend that you use only light weight wheels for your MX5 Miata like those we sell here. Unlike other vendors who rely on overly optimistic wheel weights as listed by the wheel manufacturers, we weigh each wheel that we sell to verify the weight that we list! For that reason, some of our listed weights here are slightly higher than the marketing weight listed on the wheel manufacturers' websites.
DO YOU NEED HUBCENTRIC RINGS?
Hubcentric rings ensure that the wheel is centered on the hub, even before the lug nuts are tightened down. It's a nice bit of low-cost piece of mind knowing that you can't end up with a wheel off-center due to incorrect lug nut tightening. However, hubcentric rings are NOT mandatory. The lug nuts seats are conical for a reason; as long as you tighten the lugs correctly (done by hand and in a criss-cross pattern) then the wheels self-center as the lugs are tightened. However, some shops don't take the time to correctly tighten lugs, they just zap them on with an impact gun and the Miata is too sensitive to imbalances for that to be good enough. So, you don't have to use them, but they won't hurt and they're cheap insurance. As a rule of thumb, the racers know they don't want hubcentric rings because they know what they're doing and the rings just become an extra thing to worry about... but if you're asking if you should get hubcentric rings, then the answer is probably "yes" for you. Note that all our hubcentric rings are sold as sets of four, so order just quantity one for a set of wheels.
Most modern wheels are clear coated just like the paint on your car. Therefore, do NOT use anything on your wheels that you would not use on your Miata's paint. Only clear coat safe products should be used on wheels. We like to put a coat of fresh car wax on new wheels before we put them on our Miatas here, helps keep them clean.
In the USA, the 2016-2017 ND Miata uses NO in-wheel sensors for tire pressure.
2018+ ND Miatas do use physical tire pressure sensors. We are told the new in wheel sensors do not fit Advanti Storm, customers will want to pick an aftermarket sensor for that wheel for 2018 and newer.
Please note that most 15 inch wheels for previous Miata generations do NOT clear the big ND brake calipers, even on cars without the Brembo upgrade, and the effective offset to make 15 inch clear the ND brakes will usually put the tire outside the fender lip (and the fender arch on ND is bigger than prior miatas, doesn't look right with 15 inch anyway). Thus, we do NOT suggest 15 inch choices on the ND.
With stock size 205/45/17 tires you can run offsets as low as 40mm and still fit in factory fenders with 1 degree negative camber or better, we have run 38mm with more camber. An easy upgrade in 17 inch is 215/45/17 and that fits with our wheel choices that are 42mm to 50mm offsets.
195/50/16 tire size fits within the fenders on wheels down to about 32mm offset. For customers seeking more performance in 16 inch sizes consider 205/50/16 up through 225/45 on 16x7 and 16x8 wheels with higher offset.
Torque lugs to 85 ft/lbs and check that torque again every week for first month of owning new wheels or lugs.