alpinaturbo

iTrader: (5)

Caster measurement depends on Rake.
If your chassis is flat, than you will show so much caster, if your chassis is heavily raked...caster reading will be lower..

So achieving 6 degrees of caster is possible, without rake.
Once you rake the car than 5 degrees becomes good enough.

I raked mine, and am sitting at 5.3 degrees caster with all available tools. Was thinking 7 for sure, but rake ate into it.

18x10.5 Et30 w/285/40x18 is the way forward.

But when money and all comes into play, a set of 17x9.5 Et38 NT03's with a 3mm spacer, running 275/35x17 or 275/35x17 is very appealing.
I ran 275/40x17 Hoosiers on 17x9 ET35 without any mods other than pulling/rolling rear.
They fit and 275/35x17 fits easier yet.

heel2toe

iTrader: (41)

^ I never even thought about rake but that makes perfect sense. I dont have any measurements to provide further insight regarding my setup and what yielded what number for caster but I will say that the "stock" figure I had at 3.6 was on MR Bilsteins and Robispec springs which were an even 1" drop around so it kept the stock rake. Then I swapped my Cusco camber plates for the CDR Camber/Caster and got to 5.1. And most recently I installed the Perrin PSRS along with my Ohlins and had the car corner balanced and that yielded 6.1. So the extra degree may have been from a combination of the PSRS as well as a change in rake.

Anyway, back to the topic at hand...I currently have 17x9.5 +38 NT03's which I love but this whole idea to step up to 18's was a result of the limited selection of wide street tires. Hoosier has good sizing for 17's and the 275/35 would fit well for sure but I dont want hohos just yet.

Who can comment specifically as to how much of a pull was needed for the rear? And given that the BFG's run wider than the hoosiers how much more was needed to fit the BFG's? Im getting some conflicting data which is most likely due to the various tires being used as well as the alignment so that is understandable.

But it seems that some have fit these wheels with a good roll and others are saying a serious pull is needed. Im thinking that since I will be starting with 285/30 Zii's I could fit these in phases.

Is the +30 offset enough to keep it away from the trailing arm as well as the coils in the rear. The car is still street driven so I dont want to go with a 6" spring.

And is the consensus that the front will require a 25mm rather than a 20mm for coilover clearance?

Sorry for the abundance of questions. There are a lot of great threads on here about fitment but with different tires being run as well as different brake calipers, size springs, modified suspension components and alignments its hard to drill down what's needed. I know ultimately it'll be up to me to determine specifically what I need but there are some obvious constants that I would like to be aware of.

Thanks for all of your feedback

RJones

iTrader: (5)

In my experience, a 7" spring works in the rear, but I haven't tried any longer than that. Even with the amount of rear camber I'm running, I'm not that close to the spring. When I put the 285 BFGs on with the 18x10.5 +30s, I had to shave some material off the trailing arm due to rubbing. On Hoosiers, it wasn't nearly as bad. With street tires you may be ok.

heel2toe

iTrader: (41)

Thanks for your feedback. I may pick up a new pair of springs for the rear but would really prefer to keep it 8" long. Im trying to work out all the logistics now and make sure I dont forget about any parts and expenses.

I recall reading that the 18x10.5 PF01 had spring clearance issues in the rear and required a 6" spring but that is a +38 so the NT03's would provide an additional 8mm of clearance.

As for the front you mentioned that you are using the evodave kit but you modded it to go a little wider. Was that for your 18x11 setup or the 18x10.5? Ideally I'd like to use as small of a spacer in the front as possible and it seems some have gotten away with a 20mm. I know I can get custom sized spacers so maybe something like a 22mm would fit the bill perfectly?

RJones

iTrader: (5)

I don't think you actually need a 25mm spacer. A 15mm should work in theory, as I know some run 18x10.5 +15 w/ no spacers. I actually have Voltex front fenders now, but I did the EvoDave fenders because of the 18x11s originally. You can fit the 18x10.5 NT03s w/ spacers w/o spacing the fenders out. You'll just have to shave/pull the fronts.

kyleh10

Those are my old wheels and tires! Car is looking good I used to run against max when he had the car and we swapped wheels and tires a few months before he sold the car

GTABurnout

iTrader: (1)

So last ouring I was running some Hoosier 255 R6's on the 18X10.5 NT03's And with the new aero I almost killed a rear tire on the ebrake Bracket. If I was running s 275 the tire would have been shreadded. This was with a +30 10.5 on the rear no spacer stock arms. I have since taken a flap wheel to that bracket and arm.

heel2toe

iTrader: (41)

You make a very good point; I didn't even think about that. The only thing that would void that argument is if there are spoke to brake caliper clearance issues. But from an inner wheelwell and coilover perspective it would appear that a +15 is all that is needed i.e a 15mm spacer like you suggested.

Im under the impression that fitting the front is going to be far easier than the rear so I will probably just have to mock them up when I get them and see with washers how much spacing is needed with my particular setup. And like I said I'd much prefer to keep the stock "look" if possible so if I can get away with pulling and/or shaving rather than needing the fender spacer kit that would be much preferred. Thanks once again for your feedback I really appreciate it!

What was needed on your car to make them fit and was the largest tire used a 275/35?

My season is officially over so Im now going to start tackling the list of areas that need addressing. I plan to clean up the rear trailing arm this weekend.

Hopefully the work you performed will alleviate your rubbing issues. Just curious you mentioned that you are on the stock trailing arms and no spacer in the rear. What coils do you have on the car and how long is the spring? How much camber are you running and how much work has been done to your rear quarters to make them fit? IIRC you said yours were just rolled flat, but wasnt sure if that is no longer the case...

Dallas J

iTrader: (1)

18x10.5 NTO3's clear the caliper without spacer but they're big enough that inner fender well starts limiting steering angle. Though you do have less scrub, so less rub front/rear on the fender liners.

heel2toe

iTrader: (41)

I didnt even consider steering angle...we all know how bad the turning circle is on our cars so I do not want to limit that. For a strictly track driven car that may not matter but during auto-x and dd I want all the wheel movement possible.

I am not an ME so I dont know too much about suspension geometry scrub radias's etc. IIRC as you lower the offset of the wheel, you increase scrub radius, correct? But what are the implications of that?

kyleh10

What was needed on your car to make them fit and was the largest tire used a 275/35

I ran a 5mm spacer in the rear and like a 15 up front. Also I have my rear quarter panel pulled quite a bit also shaved the control arm just a tiny bit along with the e brake mount and removed bumper bolt. Also the front fender is pulled out in the back by the door quite a bit. I ran 280 on this set up for a bit then switched to 265 cause I had a good hook on those continentals. Also as far as running no spacer up front I could clear with my super racings but when I had zeal coils it would not clear the coil and I believe it wouldn't clear the ohlins either.

heel2toe

iTrader: (41)

Thanks for your feedback. It sounds like the front will need some sort of spacer for sure between coilover clearance and limiting steering angle which Dallas mentioned and I had never even considered. My current wheel setup is actually rubbing on the inner fender well around towards the bottom so Im going to clean(smash) that area up. I will try and take photos and document the modifications I make for future reference. But anyway, Im not too concerned about the front at this point, but rather the rear.

Any reason you ran a 5mm spacer in the rear? It sounds like a little work with the angle grinder on the trailing arm and the brake bracket is all that's needed to keep it from rubbing, no? In an effort to pull as little as possible on my rear quarters every mm counts so I will not be spacing the wheel out if it doesnt absolutely need it.

GTABurnout

iTrader: (1)

there is no way the NT03's will fit the front with any camber and no spacers. They will hit the coils.

Dallas J

iTrader: (1)

Or your empirical experience says your setup will hit the coils. You != all.

With short springs or higher ride heights they do, in fact, fit. Im not saying its ideal, but if fender clearance is the issue they can go in further.

GTABurnout

iTrader: (1)

Just for arguments sake I will pull off the RPF1's and thron on the NT03's to check but I would gess the coils are the least of the issues you will have running a 10.5 +30 with no spacer on the front.