295/35/18 on 9.5" wheel
 

I know a lot of you guys are running the 295/40/18 Hoosiers on the 9.5" on fronts but is there any side effect? Hows the handling? Any sloppy feel at all? I have on order and plan on 275/35/18 on front and 295/35/18 on rears with a 18X9.5 front and 18x10.5 rear but I'd like to go square setup with the 295/35/18's if I can. I still have about a week to change as TireRack won't have my tires in stock till the 19th. If the feel is a little sloppy, is the extra grip worth it? My events are all for Autocross by the way as I'm sure that makes a difference the recommendations.

BTW another perk for me is I work in a tire shop. I can actually remount my tires to rotate as well to get better wear but handling is my main concern. Not tire life.

Thanks all in advance.

i wouldnt run 295 on anything less then 10.5 because of sidewall dynamics under load and contact patch optimization. but im sure plenty of people here have done 295 on 9.5 and will say "its fine" ;)

275 is about the max I'd go!

Well with no other input, I guess I'll stick with my 275/35 on front and 295/35 in the rear.

thats what i would do until you get 10.5 all around, then go 295 square

it'll be a while for that. The WEDs only come in +12 offset for the 10.5 which would probably require more camber then ID like to clear the front not to mention clear brakes. RPF1's probably will be next order in a square setup for but with Hoosiers.

RPF1's don't clear the...ohwait you have base brakes... :eekdance:

the +15 offset does clear the OEM BBK and my AP Racing BBK
it wasn't the case with the +30/38 though

http://www.the370z.com/members/megan...ure52922-a.jpg

yeah et12 18x10.5 would be really aggressive and prolly rub under track load

how much front camber do you run and what size tire?

The front are 9.5 +15 on 275 tire.

I had to roll the front fender to safely avoid rubbing.
The front camber was like -2.7 (track setup at that time )

What are your rears? I am running SSR Type F's, 19x9.5 up front with a 275 and zero rubbing but at factory height. I didn't know the RPF1's cleared the AP's. found my second set of wheels now I think!

Ahh gotcha i misunderstood, thought you meant you were running 10.5 et15

HEY!!! I'm workin on that ok lol. With only autcross out here in Hawaii, a BBK upgrade is on the bottom of my list of things to do. I upgraded the pads to Project MU HC+800 and I think that will be more then enough for just autocross. Also remember our average course is 35 to 45 secs so short courses also.

I run a 305/30 for my rears on my Nismo

I'm also going to be running the RFP1's 18x10.5 +15 all the way around with either the 295/35 or 305/30

The first owner of my Nismo ran 17x9.5's on it, they fit, and barely cleared. You might been able to put a business card between the two. There is some little scuff marks on top the calipers from the rim and caliper deflecting into each other under hard corning and braking.

I cant wait to see the result of 10.5 +15 RPF1 on the 370z.
Because with those 9.5 +15, I had to roll the fender and then getting those 10.5, they will be sticking out even more by 12-13mm !!!

post some good pictureS with that setup as soon as possible :tup:

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!!!

Well I'll take your word for it because I don't even know enough about wheels and suspension yet to totally understand what you just said. Care to elaborate on what you just said? :tiphat:.

BTW been watching your videos to learn buttonwillow, thanks for making those. I will be there Saturday with GF if you are there and see my car come say hi!

What i was trying to say is, since your ride height is stock, its higher for example to mine, so the wheel/tire/suspension would have a longer distance to travel before coming in contact to body work then on my car which is lower(but by no mean "low"). Also, since the length of the shock body is longer then aftermarket coilover shock bodies, under compression load, you'll bottom out( hit bump stop) with your wheel/tire further from the body work then if you had a aftermarket coilover with shorter shock bodies. This is my theory as to why you are not rubbing with 18x10.5 et15 285/35/18 up front.

Any questions you have from watching the vids? have you been there before?
i wont be there saturday, only Sunday for the time attack, ill be driving the Black JDM Civic Type R i drove at Willow springs

Chris you probably already ordered them but Costco in Waipio has pretty good deals on RE11s if you like them and they work for your size.

My only concern with Hoosiers is that you probably need more seat time with street tires before you can take full advantage of a set of race slicks. Most of those guys auto-x with us in Hawaii region have been doing it for decades. Heck, I want to say there are at least 5-8 National Championship drivers in the field. My point is they make it look easy on slicks. Learning on street tires for 1-2 season will work out any bad habits and make you much faster (1-2 seconds) on slicks.

I have not done Button Willow yet so first time Saturday, we have the Nissan competition that day. Martin's and my car are parked next to each other up at corner 3 right now lol, his rear suspension was a mess when I dropped mine off last Saturday but I am sure Steve got it figured out this week.

I have contemplated staying on Sunday for a few sessions if I can keep the GF entertained long enough. It's a long drive for just one day. If I stay there I'll look for you, otherwise have fun and be safe.

No questions probably until I get a feel for the track but definitely have watched your video about 20 times already to try to memorize the turns!

So after my further explanation, do you get what i was saying?

hope my vids help, i look forward to getting back out to buttonwillow with the Z on better tires then that vid

Yeah, I get what you are saying, but isn't the post market setup also going to be tougher to bottom out with just because it is a stiffer system that is harder to compress?

that is true, but unless you get a coilover with like 25k springs, the suspension is still going to articulate through is motion significantly

Jay, I work at the Kapolei Costco Tire Center :tup: My only problem with the RE-11's is the max rear width they offered was a 275 and I just wanted a little more. The BFG Rivals are actually a street tire but they are VERY close to a R-Compound. I won't be going with slicks for quite some time. Avery tested between the Rivals and Re-11's on Sunday in his 2 Miatas and he actually consistently ran a full second faster on the Rivals then the RE-11's. Obviously he is one of those super skilled vets that you are talking about so I don't expect as large of an increase. I actually feel pretty good as my 1st 5 events was on All season tires lol. Just gonna step it up to something stickier and see where it takes me :tup:

^ was it RE11's or RE11A's that were used against the Rivals?

Sorry RE-11a's. Still not use the "a's" part lol