Troux

iTrader: (6)

I was planning on:
Nitto NT-01
275/40/17 on 17x9.5 front
315/35/17 on 17x10.5 rear

From the pictures I've seen, these tire sizes seem to fit the wheel widths just as I would like them, with the slightest bit of outward bulge. Unfortunately, there aren't any widths for this tire between 275 and 315.

Done a little bit of reading and this seems to be the setup I want, based on available tires. According to jimlab's spreadsheet, I should be able to do this with a +50mm offset front and rear, although the spreadsheet does not tell me if wider tires will work.

I plan on getting coilovers around the same time and am aiming for a 25-26" ground-to-center on all 4 fender arches. If necessary for fitment, I would be getting aftermarket control arms at the time, as well. I am alright with rolling the fenders.

Anyone that's done these sizes before? Anything else I need to plan on, or compromises I'll have to make? If the front is an issue, I was also considering a more expensive option of Burnout front fenders and 10.5" all around (on 315s), and hopefully it won't look too weird only having the front widened.

Troux

iTrader: (6)

Nobody? Would have at least expected a bunch of people telling me it's impossible by now.

ARD T2

iTrader: (22)

OK so the rear won't work.

Measure the total spacing you have under that fender and see if it will match with your shoulder to shoulder width of the tire.

10.5 +50 is uber close. Not sure if you're going to run into the trailling arm, even if upgraded. With that size tire i'd be concerned.

275/40/17 imho is just tOO TALL for the Front Fender Arch on the FD. I've tried this before and had serious scrub issues.

You pretty much max out at a 265/40/17 diameter. Anything can be done if you put the time into it.

Just some food for thought.

Troux

iTrader: (6)

You think the 275/40/17 would be too tall even with rolled fenders? The 275 has a tire diameter of 25.66", vs. 25.35" for the 265/40/17. The rear (315/35/17) came out to a tire diameter of 25.68.

I planned on running very stiff shocks and springs, so that should prevent rubbing quite a bit.

Another idea was going the same widths on 18" tires. Then I would run 275/35/18 and 315/30/18, giving tire diameters of 25.58 and 25.44. I was mainly worried about sacrificing performance going to 18" vs. 17" wheels. I'm mainly aiming towards road course, vs. autocross. Let me know what you think about that plan. Thanks!

ARD T2

iTrader: (22)

The issue isn't hitting the outside of the fender as much as it is hitting the "fender liner" location.

I know guys who've made it work, just wanted to let you know that it's not PnP.

If you go 18's then you should DEFINITELY ROCK

295/30/18 Front, great tire diameter and 315/25 or something like that.

Rishie

Troux

iTrader: (6)

Like I said, though, I'm worried about losing performance to 18s. I plan on around 400WHP (LSx), but I'll let you be the judge on what is enough sidewall. I found a few tires that offer a 295/30/18 and 315/30/18, so those should work...

Edit: Those tires are almost twice as much as the NT-01s!

paul_3rdgen

iTrader: (6)

Why don't you go with a square setup? Something like an 18x10 +50offset and run 285/30/18 on all four corners, this will be your best setup for the track. You can rotate and you will have no problems hooking up the rear with the power you mentioned.

Troux

iTrader: (6)

I'd prefer something a little wider, and from what I've seen, I think a 305 would fit best for a 10" wheel. The problem is finding tires for the sizes I want.

paul_3rdgen

iTrader: (6)

According to who? Check the tire manufacture's web site for recommended wheel width, from what I see a 305 belongs on a minimum of 10.5in wheel.

Troux

iTrader: (6)

I found a good set of tires I like with that size. Yokohama Advan A048. +50 offset on all 4 corners will fit 285/30/18s just fine, or should I choose anything smaller? I assume this will still require rolling and aftermarket suspension parts?

Edit: This is a 24.97" tire.

paul_3rdgen

iTrader: (6)

You are going to need to roll your fenders, you probably need aftermarket trailing arms, and you definately need coilovers.

Troux

iTrader: (6)

Will do. Thanks for your help, Paul and Rishie! Finally got a choice that's set in stone.

ptrhahn

iTrader: (9)

285/30/18 all around on 18x10's is just about the best track setup. The short tire up front allows you to run as low as 25" at the fender lips, and the same size all around really helps you manage tire wear.

18" wheels aren't *necessarily* a compromise.

ptrhahn

iTrader: (9)

Per request of the OP:

I think that alot of the "18's are a compromise" feeling was from when this car came out 12 years ago, and 18" rim and tire choices where limited.

Sure, an 18" wheel will weigh more than a 17" of exactly the same brand/model (18x10 vs. 17x10, same offset), but typically it's only a pound or two. Often too, unless you're talking about custom modulars, the exact same size/offset in 17 and 18 may not be available, and you're comparing different brands anyway. However, it's not uncommon for an 18" TIRE of the same width (say, 275/35/18, or 285/30/18 vs. 275/40/17) to actually weigh less (sence there's less rubber obviously). This may actually be better, because removing weight from the outside is probably better than the center, right?

The other issue is sidewall size at the rear, for traction w/ big horsepower. This applies mostly on the road, from a launch or roll. R-compound tires on a racetrack is less of an issue. There again, I think that since so much more is available in 18" tire sizes, you can mitigate this. In 17", you've basically got 275/40/17, and that's it. There are very few 315/35/17's, and even fewer rims to be used to fit them on an RX7, and they still don't really fit well. In 18", you can run a 275/35/18, which has plenty of sidewall in my experience, or use a 285/30, or even 295/30 that can still fit the car. 295/30 is a Porsche GT2 rear tire.

Bottom line is, you can get plenty of VERY light 18" wheels, the tires are often lighter, and are available in many more sizes, AND you're more likely to be able to get a shorter tire (of reasonable width) on the front (crucial with these cars). It all comes down to what you do most often with the car.

I caveat this by saying I've owned or at least driven virtually every combo available:

295/30 on 18x11 rear, 285/30 on 18 x 10.5 front (Kenesis, PZero's)
285/30 all around on 18x10's all around (Technomagnesios, Hoosiers)
285/30 on 18x9.5 rear, 235/45 on 18x8.5 front (Advans, So2's)
275/35 on 18x10 rear, 255/35 on 18x9 front (BBS, Toyo T1S)
275/40 on 17x9.5 all around (SSR Comps, Victoracers)
275/40 on 17x10 rear, 235/45 on 17x8.5 front (Fikse, So2s)
275/40 on 17x9 rear, 235/45 on 17x8 front (SSRs, RE71's)
255/40 on 17x9 all around (SSRs, A032s)
245/40 on 17x8 all around (SSRs, RE71's)
Stock


Just my 2 cents worth. Maybe I can save everyone else from buying eight sets of wheels!

owen is fat

18x9.5 front and 18x10.5 rear with 285/30 front and 295/30 rear
it would look great, feel great but you cant rotate tires for longer life and you end up being limited in tire choices because of the stagger size f/r.

but you are probably just much better off running the tried and true 18x10 +50 all around with 285/30r18 tires. pricey but worth it.

if you can roll the fenders a little you can stretch that 285 out on a 295/30r18 out back.

if you do want big monster wide rears then you need to look into the pettit rear overfenders / flares to run a 335 on something like a 17x12 or 18x12 but its all money money money.

Troux

iTrader: (6)

^I was considering fenders, but I'd rather spend big money and do it right, which means that's a ways down the road.

I was also thinking about a slightly wider tire (295/30/18) on the same 10".

ptrhahn

iTrader: (9)

^^^^
I don't think that 10mm is worth not being able to rotate.

Troux

iTrader: (6)

No, I meant 295s on all 4. Would this be any more of a clearance issue with rolled fenders? It's still under a 25" tire diameter.

Troux

iTrader: (6)

Anybody? 285s vs. 295s?

Troux

iTrader: (6)

I also just noticed that 10" wheels are recommended (in jimlab's spreadsheet) to get a +57F and +44R offset. Seems like +50 on all 4 corners would fit odd, am I right?

Specter328

iTrader: (2)

+57 up front would be odd. Trust what everyone has been telling you about 18x10 +50 with 285/30 18 all around. Many track FDs run that wheel/tire combo.

ptrhahn

iTrader: (9)

You want the same offset all around for the ability to rotate. If you want a little more frontspacing at the rear, run a 5 mm spacer.

I use the spacer in conjunction with some extended shank lug nuts.

Troux

iTrader: (6)

That's what I'm leaning towards, and I'll gauge my rubbing/clearance issues from there. Thanks to the club!

owen is fat

stick with 285's because there are more tire options and more likely to be in production than 295's that are on less cars from the factory and less volume in production.

there is almost no differece between the 285's and 295s both mounted on my 18x10's.

285/30r18 take-off tires are dirt cheap too... Rcomps or streets.

Troux

iTrader: (6)

^In response to that, I was just wondering, if I found a good set of 295/30/18s for a similar price, would there be clearance issues keeping me from choosing those over 285s?

Also a new question arises that I didn't know was a problem. Are 18x10 +50 wheels going to clear my stock brakes?