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17x9 45mm Offset.. How??

Posted: Wed Jun 17, 2015 6:28 pm
by carsandcameras
I know this topic has been beaten like a dead horse, but I recently bought 17x9 45mm offset RPF1s with Dunlop Direzza ZII 245/40 tires for my 2007 GT 6MT Miata. The only other mod right now is the Hard Dog Double Diagonal.

I also bought some of the Taiwanese BC Racing coilovers (7k/5k spring rates) and have not yet installed them.

Here are photos of the wheels/tires mounted on bone stock suspension/stock alignment.

Rear:

Image

Fronts:

Image

I've read/been told that I'll just need a light roll in the front, but judging by the way they look now, I just don't see how these bad boys are going to fit without an insane fender pull and a crazy amount of camber when lowered to 13" (the highest setting on the BC coils).

Can anyone lend me some advice? Thank you in advance!

Re: 17x9 45mm Offset.. How??

Posted: Wed Jun 17, 2015 9:28 pm
by Brian
Yep, looks bad now...but with lowering all the suspension arms swing inward, and with some camber the tops of the tires will tip in too. That fitment with the 245mm tires needs decent roll on fender lips but it all works once lowered, 1.5 camber or better, and rolled fender lips. And that 1.5 negative camber is not a crazy amount on car this light unless your mileage is almost all freeway (most of us racing run MUCH more).

Re: 17x9 45mm Offset.. How??

Posted: Thu Jun 18, 2015 4:31 am
by carsandcameras
Brian,

Thank you so much! If anyone else had told me that, I would have been hesitant to believe it, but because you have just a little experience with these cars, I'll believe you. :D

I autox, but I also do a lot of highway driving, so I'll probably stay very close to -1.5 camber (if not -1.5 camber).

Thanks again!

Re: 17x9 45mm Offset.. How??

Posted: Thu Jun 18, 2015 5:17 am
by Castro
Same wheels on black with koni/progress combo, -2.5 camber in the front, -2 in the rear and a moderate fender roll and it clears fine. With coilovers should work even better! I daily drive and autocross mine.

Re: 17x9 45mm Offset.. How??

Posted: Thu Jun 18, 2015 9:45 am
by Brian
Castro wrote:Same wheels on black with koni/progress combo, -2.5 camber in the front, -2 in the rear and a moderate fender roll and it clears fine. With coilovers should work even better! I daily drive and autocross mine.

Thanks for the pics and specs Castro, looks great and perfect example of the greater camber many of us are running.

Re: 17x9 45mm Offset.. How??

Posted: Thu Jun 18, 2015 10:38 am
by Yariman
Here is almost your exact setup. I am running the BC Coilovers as well Front 12.75 rear 13. Front is -2.7 camber rear -2.2 so probably more than you'd like to run.

This is with 255/40/17 and I did a pretty good fender roll. Only place I rub now is on the very inside of the tire if I smack a decent bump.

Image

Re: 17x9 45mm Offset.. How??

Posted: Thu Jun 18, 2015 4:38 pm
by Brian
Great pics guys, great looking Miatas!

Re: 17x9 45mm Offset.. How??

Posted: Sat Jun 20, 2015 7:56 pm
by carsandcameras
Thanks everyone! I got my fenders lightly to moderately rolled yesterday in the front and rear. I'll probably go with greater than or equal to -2 degrees of camber and then decide if I can back it off from there.

Castro- I too daily drive and autocross my car. How quickly do you go through tires? I'm fine with having a decent amount of camber as long as I don't have to buy tires once a year.

Re: 17x9 45mm Offset.. How??

Posted: Tue Jun 23, 2015 10:50 am
by Castro
Cant really asnwer your question because I have only owned my MX5 for 6 months. Althought I dont think camber will be so much a factor as to tire choice, how many AX events you are running, how many miles you are driving on the road and how often you rotate the tires.

I have 2 sets of wheels. I drove Pilot Super Sports for 6 months averaging 800 miles per month and about 60 AX runs, rotating my tires monthly I got even wear on them and have about 75% thread left. These are now my DD tires.

With the setup in the picture with the Rival S I would expect about a year because they are super soft. But the Rival S will be driven at, to and from AX events only.

Also when I installed the koni/progress combo -2 degrees was the minimum negative camber i could get up front. so you might not be able to reach -1.5 with coilovers.

Re: 17x9 45mm Offset.. How??

Posted: Wed Jun 24, 2015 8:47 pm
by carsandcameras
Also when I installed the koni/progress combo -2 degrees was the minimum negative camber i could get up front. so you might not be able to reach -1.5 with coilovers.
Ah, thanks! I autox 6-8 times a year, and drive roughly 12k miles a year. Do you happen to know what your ride height is?

Priority #1: Keeping the setup from rubbing. I can always crank up the dampening and preload to keep it from rubbing, but it'll give the car a paint shaker ride.

Priority #2: Not spending $$$$$ on tires every year. If I have to run an insane amount of camber (and can adjust to less than -2 degrees), I may back down to 235 tires.

Priority #3: Contact patch/grip.

Priority #4: Looks. I'm a big fan of meaty tires.