I saw my first Z06 last week. I noticed they run 17"ers on the front and 18"ers out back. Has anyone tried this on their FD? Looking at alot of cars on this forum over the past few weeks I noticed the rear always has more of a gap out back. Not sure if it they were stock springs or not.

Ive been hoping to find the perfect size/offset wheels now for a few weeks and after reading all these threads, Im starting to doubt Ill ever find a set of wheels.

 

I'll let Rishie take care of your needs! He's got a line on Volk, Fikse, SSR HRE, whatever your pockets can afford!

 

I am an avid FC owner, 3 of them, and I do stagger for street. This is mostly due to fender clearance and such. I really like it. Third gens are a different situation for me. I have yet to setup staggered diameters front to rear. So input from the FD guys would be good on this one, as to performance.

On the 3rd gen the advantage would be an aesthetic one as well. Really depends on what size tire you run on the front, as well as how much you are looking to lower it.

If interested in a 17" run a 245/40/17 and in the rear run a 265/35/18 or 275/35 if you want to go over a little. You should be fine with +40mm offsets front and rear. That's a good thing as it's pretty common. In turn I would advise for a 17,8.5 front and 18,9.5 in the rear.

The real question is, "What style wheel do you like and what can you pocket afford." Let's eliminate some variables first, and see what we're left with on fitment.

See ya, Rishie

So you're the one who got the SSR's from AZEEM. How funny, cause I hooked him up with those. He's a really cool guy, so jealous of his Lightning. Wonder if he did sell the FD, do you know?

 

Yeah, I'm the guy that bought your SSRs from Azeem. We talked a few times over the phone. I was actually ready to buy a set of CCWs from John Purner, but Max Cooper, Steve Cirian, and Azeem Raja talked me out of this plan. Apparently my stock style springs won't work with the 10 x 18, 2-inch offset wheels John was going to hook me up with. I saw Azeem's ad in the partstrader.com. He's a good salesman, and I bought his pitch. Azeem's story was that he did sell his FD.

The wheels were in new condition. There was a 2-inch scratch on one of the rim lips (one of the 8.5 x 17s). It doesn't bother me much since they're for racing-only. I would like to find some clear-coat-in-a-bottle and touch up the scratch on the rim-lip. I'm just **** about stuff (hee hee).

Keep up the good work hooking us up with quality wheels and tires! Don't let us compromise on sh*t. If we can't do it right the first time, let us save our money so we CAN DO IT RIGHT THE FIRST TIME!

 

FULLY AGREE WITH YOU ON THAT. Cutting corners doesn't get you anywhere except backwards.

Thanks, Rishie

 

Actually this would work with John Purner's CCW wheels. With 10 x 17s all around John uses a different offset for the rears to clear the rear trailing arms. If you used 10 x 17s front and 10 x 18s rear, you could use the same offset front and rear and maintain the same track width fr/rr; but you still can't rotate the tires (shoot!).

The C5 uses 9 x17 fr and 10 x 18 rear to increase the diameter of the rear tires. This is to maintain the rear-end gearing in back, as much as improving ride comfort with taller sidewalled tires in back.

 

"as much as improving ride comfort with taller sidewalled tires in back."

Is that right? I thought 18"ers normally had less sidewall when compared to a smaller rim.

 

Yes, if the overall diameter of the tire must be maintained at 24.9 inches or so for our cars. Not all cars have 25-inch overall tire diameters.

The last time I checked the C5 carries 285/40-18s in back. If you all calculate the overall diameter of that tire, it is 27 inches. Subtract from that, 18 inches for the wheel diameter and divide by 2 you get the sidewall height, which is, 4.5 inches. This is the very same sidewall height of a 225/50-16. Go through the calculation--the overall tire diameter is (24.9 - 16)/2 = 4.45 inches (slightly shorter actually!).

So the C5's ride comfort will be similar to a stock FD wearing stock wheels/tires, based on similar tire sidewall heights--get it?

The 27 inch overall rear overall tire diameter of the C5 is needed for the rear end gearing to be correct.

 

I was thinking of doing that setup also...
Less sidewall in the rear for better launches/traction and more in the front for those stupid potholes, dips, bumps, etc.

I've only seen one FD with that setup but it was for sale and it was a while ago.

(I plan on switching to coil overs beforehand.)
I don't know what offset to choose though, maybe 45 f&r?

Corvette Z06
17"x8.5"f,18"x9.5"r 17"x9.5"f,18"x10.5"r
front: P245/45ZR-17 front: P265/40ZR-17
rear: P275/40ZR-18 rear: P295/35ZR-18

I think 8.5"F & 10.5"R sounds good to me
What do you guys think?

 

Two inches wider in back compared with the front will have your car pushing like a NASCAR PIG!. But if that's what you want, and you've got money to burn...

10.5 wide in back will require 18s to clear the rear trailing arms, and a 7.75 inch back space. Assuming an 11.5-inch overall rim width, that makes the offset at 51 mm. It would be best if you went with M2 rear trailing arms to maximize clearance. Depending on the tire size you choose, you may also need to roll the rear fender lips. 8.5 front will be ok with 40 to 45 mm offsets.

 

8.5's on the front and 9.5's on the rear.
235's on the front and 265's on the rear.

This combo should fit with the car lowered and without any rubbing (assuming correct offset).

But is it best to stagger 17"F/18"R or not?
...if not i'll +2 size to 18's all around.

I currently have 17x8F(225's) & 17x10R (275's). Excellent feedback, I stay confident when getting squirly in the turns. Never had stock wheels, so I don't know how that feels.

What does a fat Nascar pig mean? ...A loose rear end? Please trasnlate in "Tires for dummies" talk.

 

with 255/40-17 front and 285/30-18 rear. More contact patch all around, with enough understeer dialed in without having the car push like NASCAR race car (pigs...they weigh 3800 lbs, and are set up to understeer). 48 to 50 mm for the 9 x 17, 51 mm offset for the 10 x 18. Clearance from stock rear trailing arms should be ok with 7.5-inch back space for the 10 x 18s (assuming 11-inch overall width).

 

1. Is a staggered setup (17"'s F / 18"'s R) better than the same size (17-F/R or 18-F/R) front and rear?

2. For an RX-7 FD3S is the wider a rear tire the more understeer?

3. To have neutal steering should we go closer to the same width front and rear?

4. Are 18's really that bad? I think a +2 size looks cool but am I sacrificing comfort (potholes, dips).


Please translate replies in Tires for Dummies jargon...
[Yes/No, Tight/Loose, Sweet/Nasty, For Sure/As If, Good/Bad?]

 

1....Better ? The fact I dont know of one racer using this setup..says something about it to me....dont you think.

2. YES wider in the rear would create more understeer

3. Yes..the FD is very Neutral...same size front/rear would keep it that way...other things like suspension components can effect this also

4. 18's are not really bad...If your roads are **** and your FD is daily driven you might want to think about it...But I dont mind the ride one bit so far..My car is setup up fairly tight...GC coilovers...450/375..koni set on almost full firm...I have racing seats (sparco supersports)..m2 suspension components and a eibach front sway....tires are low pro..235x40x18 and 265x35x18...so the ride is STIFF...but I like it.

 

1. Not many FD enthusiasts have tried this, so there's no real informed opinion on the matter.

2. Yes, wider tires in back dial in understeer (known as push, or plow, where the front end slides first at the cornering limit).

3. Yes

4. For public road use, 18s are bad for driving over chuck holes. FD enthusiasts that choose 18s for the public roads, want an updated look. IMO there aren't any real performance benefits that are worth sacrificing the money and damage that might occur from running 18-inch wheels over miles of chuck holes.

 

I was running 275's in the rear and 215's front. It was pretty squirly when I pushed it, now I know the Nascar pig term.

I'm running 255's in the rear now and it is way better. So 255's front and rear sound good but if they are different offsets, you still can't rotate the wheels...correct?

I tried reasearching the Corvette forums but still can't figure out why they have 17F's & 18R's. If the rear 18's is to correct the gearing, why don't they have 18" fronts?

 

one question , GoRacer....why did you put narrower-than-stock tires in the front??

 

My rims are actuall 17x7.5". The previous owner didn't know anything about the car at all and he spent at least $10,000 on it but only drove it for 1,000mi in one year. Anyhow, it had 275's on the rear (didn't notice the front's, they were brand new) and I didn't think it was possible to put that size tire on such a small rim. They will be for sale soon (also fits honda).

 

OMG!

 

What's the deal with the Corvette C5's having 17's up front and 18's in the rear. Setting aside that the rears are wider because that doesn't answer the question, since you can put wider 17's in the rear.

It seems to me to be some kind of compromise of handling and comfort. Better launching and cornering with lower profile rear tires but more sidewall up front for more comfort on our unforgiving roads.

Can anyone correct my guess with a real answer?

 

pardon what may be my ignorance, and this is a bit off the original thread's subject...but i thought low-profile tires were BAD for launching. (look at any drag car and you'll see TALL tires.)

a taller sidewall has more flex, and can help dampen (or rebound from?) the initial torque of the wheel's rotation.

i'm right, right?

 

Drag slick tires have soft side walls and some are even wrinkled which flex and the tire expands and holds more air as it gets hot. It's probably just the tread on the low profile ultra high performance street tires that give a better launch than taller high performance or all weather tires.

But my last msg was cause we never answered the original question. My best guess was the 18's in the rear was for handling and 17's in the front was for comfort on bad roads. If the 18's in the rear were for gearing they coulda put 18's in the front also.

I even tried searching the Corvette forum but no one knows. Oh well, guess this thread is dead.

 

I recently upgraded to Konig Villains 17x8's w/235-40-17's in the front and 18x9's w/275-35-18's in the rear. The look is great! My buddy with 17's all around is very envious. And I know why. The stagger look is incredible – after looking at my friends car I felt the shape of the car demanded larger wheels in the rear. I only wish the 17’s did not look so small in comparison – But I did not want to try and fit 18's up front. I will post pics tomorrow.

 

GoRacer, I think the 17/18 choice was made for both performance and aesthetic reasons on the Vette. The diameter of the rear wheels is larger than the fronts on the Vette, so different sized wheels makes sense from a performance standpoint. The tires are all the same diameter on the RX-7, so different sizes front to rear doesn't seem to offer any performance advantages for this application. It probably isn't a big difference in performance, and it may still make sense from an aesthetic standpoint, however. It still seems like a "valid" choice to me, and might work pretty well with something like this setup: 17x9-255/40-17(F) and 18x9.5-275/35-18(R).

There is a point at which the sidewall gets too small, and grip is compromised for turning. You probably get better handling response with the smallest profile possible, but it comes at the expense of grip and the ability to absorb bumps at some point. For launching, tall sidewalls are better, but as was mentioned, street tires with grippy treads tend to be at the lower profile end of the market. Still, I bet you'll get better launches with a 16" or 17" wheel than an 18" assuming the same tread, width, and diameter.

I would guess that the car will handle better (higher cornering speeds and lower laptimes) with 17" wheels than it would with 18" wheels. I've got 18" wheels for the track with 30 series tires, but I made that decision mostly because I could get wider tires with the right (stock) diameter in the 18" sizes, and because I could use the same offset for all four wheels, which means I can rotate them. A 17x10" wheel that you could rotate with a 285/35-17 tire would be ideal, because you have more sidewall than the 18s and you get the same width in the right diameter, but no one makes tires in that size. And you can't fit big brakes under 16" wheels as easily as 17"s, so the 17" wheels win on that front. There are compromises for each size, so you just have to choose the option that seems best overall. 18x10" wheels with 285/30-18 tires was the option I was most pleased with, but it is not perfect.

TireRack or Grassroots Motorsports (I can't remember which) did a test of different plus size wheel fitments on a BMW and found that the middle size (17" I think, versus 16 and 18) offered the best overall performance.

-Max

 

Yeah, it's Goldie Locks and Three Bears...17-inch wheels/tires are "just right"