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.
Offset and Size
Offset causes a lot of confusion. Here is a simple explanation. If the rim is 6 inches wide, and the mounting surface of that rim (backside of the bolt holes), is 3 inches from either outside edge, that rim has a 0 offset. To the extent that a rim's mounting plane is offset from that zero position, that offset is measured in millimeters for Japanese cars. For the 2006-2015 Mazda MX5 Miata the factory offset is 55mm for the 17 inch size. Street users considering a wider stance but staying with stock width tires may consider offsets down to about 40mm without rolling fender lips or worrying about extra aggressive camber settings. For Miata owners looking to go wider than the factory 205/45/17 MX Miata tire size, we suggest our many 48mm offset choices in widths of 7.5 and 8 inches as the most easy fitments. However, as you push out with offset and lower the car you can still clear stock fender lips if you use conservative size tires and/or more aggressive camber numbers. Thus, 40mm offset Konig Ampliform 17x8 wheels can fit stock fenders with a 215/45/17 tire if you max the camber setting (and the MORE YOU LOWER the car the more negative camber you can get and it becomes possible to fit even 225/45/17 at 40mm offset if lowered enough). Our 45mm 18x9.5 Enkei RP-F1 is intended as a race application only. Please
contact us if you have any questions on appropriate offset for your intended use.
MAX SIZE
Folks ask every day what is the MAX size they can install on the 2006-2015 MX5 Miata without rolling fenders? The max tire size that fits in stock MX5 Miata fenders is 235/40/17. Note that offset is critical, 48mm to 50mm choices get that 235/40/17 under stock fender lips easily, choices that are 45mm offset usually need some fender lip roll, or a lot more negative camber. Thus, our popular autocross 17x9 Enkei RPF1 with 45mm offset often requires a fender lip roll for 235/40/17 or more tire (STR customers often using 255mm wide tires but that requires lips rolled up flat inside). A 45mm with just 225/45/17 tire and camber of -1.2 or more usually clears stock fenders, run better than -2.0 camber all around and 235/40 will usually clear stock fenders. Variables include height of the car, brand of the tire (race tires typically over the listed size). As odd as it sounds, lower car has easier clearance for more aggressive offsets because you have access to much more negative camber that tips tops of tires inward and lowered enough the suspension arms start to swing inwards too. The limit without fender flares is typically 255mm, we have run as much as 285mm and 295mm tires using our fender flares which are available on this site.
Lug Torque
Torque lugs to 85 ft/lbs and check that torque again every week for first month of owning new wheels or lugs.
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.
Lug Torque
Torque lugs to 85 ft/lbs and check that torque again every week for first month of owning new wheels or lugs.
Wheel Care
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. 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.
