By all accounts, RPF1's will NOT fit over the Sport brakes, so if you're running base brakes, you're good, otherwise... might wanna do some research.

their's no way et15 18x10.5 is going to fit up front with any reasonably wide tire AND be used for track use without fender modification.

18x9.5 et15 is the same outside fender clearance i run currently which is 18x10.5 et28. And i run -3.2 camber. Ive seen some street guys run 18x10.5 et15 with stretched tire but that hardly counts as "fitting" especially under performance usage

I should have said I want 18x10.5 +15's but hey if they don't work then there is the option of 18x10 +38 and run spacers. I've also been eyeing the Cosmis Racing wheels in a 18x10.5 +20 or 18x10 +25 It depends on the brand of tire, size, side wall, camber, and how low the car is as.
I'll post pics as soon as I have some and what I end up doing. I just want to get the largest amount of rubber up front as I can, and run squarded up so I can rotate tires.

If guys are running 20x10 +25 on a lowered car
http://www.the370z.com/members/ryan9...3-img-0065.jpg
and 20x10.5 +30 there should be room to play with.
http://i1282.photobucket.com/albums/...ps54d6ac69.jpg

I thought the OEM BBK were slightly smaller than the AP Racing BBK ??? The sport brake arent 14'' disk ? APR are 14.25''. This is why I always thought the APR would have less clearance.

anyway if this the case the OP must get the base brake OR go with the AP kit from what you are saying? The RPF1 will fit no problem, and good luck with the 10.5 +15 as Ive been saying , the 9.5 +15 is pretty much the only one that will work with some more neg Camber and some fender rolling.

I always been taking about the +15 offset, since I always mentioned which spec im talking about. The others offset wont work unless you run spacer.

I'm no tire+wheel wizard, but just to aggregate and comment on some things people have said above:


I personally run 10.5" RPF1's with 285/35 square with no spacers and have had 0 issues with spacing/rubbing/hitting the wheel wells so far.

which offset do you have ?

Which brake do you have ?

arent you on stock ride height suspension?

18x10.5 RPF1 only come in et15

strange but interesting.. :tup:

I almost want to doubt what GSS138 said about what he has !! hehe
so my eye were probably playing games with me when I saw the top of the front tire were sticking out on the front fender which made me to roll them.

maybe some suspension binding? when I first installed them on the car,, soo Im a bit disturbed learning this.

bottom line is then I will try to get my hand on a 10.5 next year :)

I have a stock suspension and sport brakes, I didn't mention that they are 18" wheels-track only. I have no spacers, just hub centric rings.

I am good with tires, I know very little about wheels besides their dimensions and how much they weigh. If you want to know more private message Mike at corner 3 garage or if mike sees this post maybe he can comment. Mike is the one running the extreme speed promo in these forums that is endlessly bumped. :P

He is the one that did my setup so he can answer better than I can.

But yeah I have stock suspension, 18" x10.5" RPF1's, Hankook rs3's 285 square, sport brakes, no spacers and they work fine. Martin82 on these forums whom I track with once a month runs I think an identical setup and he has 1 way coliovers and cambers-not sure if he uses spacers or not though.

the front 370 suspension does have alot of camber gain under load, but when i test fit my rear 18x10.5 et15 with 285/35/18 tires even with -3.2, i didnt feel it would fit without "self clearencing" under load LOL

I feel the key factor here is stock ride height.

Martin is on Enkei NT03 with 18x10.5 et30, no spacer front, and spacer rear (20mm). from my testing and research, et28(which i run) to et30 (what martin and what the Robispec 370 used to run) for 18x10.5 is ideal, since it pretty much takes up all the inside space it can before hitting the knuckle arm. I feel if you end up getting coilovers and as your pace gets faster, you will start to have rubbing issues with the et15 10.5s

Well turn 6 at Big Willow has put me in Dukes of Hazard mode before but only once or twice per day usually :icon17:

and just to add some tireporn:

http://imgur.com/ziFg8Xs

Rpf1 will clear diameter wise but high offset need a spacer. I have a +45 with a 20mm spacer. 15mm would have worked for a +30 overall but I didn't want to do the work of installing the longer studs.

OP rule of thumb is dont go over 20% width. A 9.5" wheel can support a 289mm tire and be fine.

Stock suspension and with a iPhone and a level I got -0.9 front left, -0.5 front right, -2.1 rear left, -1.5 rear right. Fronts stick out but I need -3, -2 camber to pull them in and get a good track number. Fronts 9.5" +25 on 255/40 and rear is 10.5" +15 285/35.

http://i39.photobucket.com/albums/e1...psdb3541a6.jpg

http://i39.photobucket.com/albums/e1...psc65c7862.jpg

just saying at sotck ride height and 18s you prolly have a long way for the suspension to travel before even getting close to body work. and you might also be hitting bump stop before you even get to the point of rubbing

I run the 295/40s on one set of wheels that are 18x10 and one that are 18x9.5. No adverse affects and no feel difference between the two.

255 is not enough tire under heavy braking load. Thats what I'm on now. Going with a 275/35 and 295/35. Hoping TireRack gets my tires in and ships them out tomorrow! Then Happy B-day to me!!!