2002 Miata SE Choosing Tires and Size Help

[Sojourner]

Hey guys, I have purchased a 2002 Miata SE. Im sorting out a few things, car is in really good shape overall. Im preparing it for autocross to join you all later this year and beyond. I have a few questions.
Mods:
Enkei RPF1 wheels, 16inch (205 tire)
Feal Coilovers
Swaybars
Endlinks
Roadster Muffler
AEM Intake
Porterfield Brake Pads
Stoptech rotors

1. What class is the car going to be in? If Im understanding correctly would it be STR?

2. What tire do you recommend? Ive been looking at RE71R's, should i consider others?

3. What tire size do you recommend? The standard tire size is 205/45R16. That is what is on it now, so the wheels are size approximately the same (im not sure the exact wheel width yet). The 205/45 tire is $25 more per tire than a 205/50. The 205/45 tire seems to cause the speedo to read on the low side, so 205/50 would correct that somewhat. The 205/50 tire would give slightly more clearance (about 10mm taller). However, the 205/50 tire would have more sidewall which will affect looks and performance/gearing. For anyone familiar with this setup, what would you recommend?

Thanks all! hope to be out there soon.
Jason

[rodhx]

Yep, that certainly sounds like an STR car based on the mods you listed. You can run up to 9” wide wheels. The STR NB setup is usually 15x9 wheels and 225/45 tires, at least for the NB1. There are a few 245 15” tires now that might be usable but I’m not sure. Tire choices are getting very limited in 15” & 16” sizes. I would run the least expensive of the RE71R and the new Falken 660. My guess is your existing wheels are 16x7.

Btw, if your speedometer is slow with the 205/45 it will be even slower with a 205/50. The taller tire will spin slower to cover the same distance. Given the two choices you mention I would stick with the 45.

[Sojourner]

Ya Im going to stick with the 205/45. I lifted the car last night to adjust ride height and noticed the RPF1's are indeed 16X7. This will put me at a disadvantage in STR with only 205's I assume? So before I think about putting on some 200 tires i probably need to decide if i want to sell these RPF1's and get 16x9.

I think the speedo is reading revolutions. Because the 205/50 tires are larger circumference and it covers greater distance for each revolution, the speedo will read higher with them in comparison to 205/45 tires.

[Cameron Hall]

You will do much better if you move to a 15x9 wheel rather than a 16x9. The 15s will be lighter and have more tire choices when it comes to autocross. When I had my 02SE I ran it in ES with a set of factory NB 15" wheels.

A 225 Falken RT660 on a 15x9 is likely to be your best bang for buck.

You may want to keep the RPF1s to use as street tires so that you don't wear out a sticky tire just driving around on the street.

[Sojourner]

Thanks ya im looking at 15x9 now. Looks like will require a slight fender roll? Anything else fit wise with coilovers and a 15x9?

Also, I was looking into a roll bar, but with the extra cost of wheels i may not do it. Plus it adds weight. Autocross certainly doesn't need a roll bar. Thoughts?

[rodhx]

Only add a roll bar if you plan on track days. A proper offset 15x9 will not require a fender roll.

You will be at enough of a disadvantage in STR simply by not having an ND or s2k, so don’t sweat it too much. An STR NB or NC are tons of fun on a local basis though. I’d love to have a STR NC for both autocross & track use.

[Cameron Hall]

You are correct, just a fender roll needed. You'll probably want to add a 1-1/4" Racing Beat front sway bar and some sway bar reinforcements too, but that has nothing to do with fitting the wider wheels.

And as Rod said, only add the roll bar if you want to track the car. It's always easy to add one later if you change your mind. If you do decide to get a bar, check out Kirk Racing in Gardendale.

[Sojourner]

Ok. Ive heard some say no fender roll and others say a fender roll is needed. Guess i'll have to see after i get them (if I go that route) and how they fit with the Feal Coilovers and some negative camber.

I have the flyin miata sway bars (front and back).

[rodhx]

I ran my STR 99 on 15x9s with 225/45 and never even consider rolling the fenders. Tirerack C3M wheels...36mm offset.

[Cameron Hall]

I ran my STR 99 on 15x9s with 225/45 and never even consider rolling the fenders. Tirerack C3M wheels...36mm offset.

Interesting. I guess I knew the plan was to party with my NB, so I just rolled them flat. The car fist 15X10s and 245s great now though...