LOL, correct. I haven't been in the forum for weeks.
You'll need to roll your fenders if you use the 245/40 tires; you can use either 235/40 or 225/40 without rolling, but your tires will stretch.

That's not a problem thanks I really appreciate the help I'll be ordering tonight

Wow so after looking threw 30 pages and not seeing a previous post that answers my question I am going to ask. I apologize if this has been asked I am not lazy but i am also not a masochist lol.

So I need to know what is the "best off-set" for 18x8.5's with Eagle GT, 255-40-R18's wrapped around them. I don't want to have to roll the fender and i do not want to run staggered. Just worry free driving bliss :). I quoted best because its kinda subjective, but i think most people will get the idea. The fitment that will look good but not rub...

My RX8 sits a bit lower than most others I have seen, I have not personally lowered it however that doesn't mean the previous owner didn't. Sorry didn't get to talk to the previous owner, bought the car from a dealer.

I am also curious as to why this seams to be such an unpopular combination to run being as i haven't seen it in 30pgs of searching. To me it seams like a good compromise between wheel Dia and width for looks, but also lets you find a wheel and tire combination that can be lighter than stock without breaking the bank. Would any one care to enlighten me lol?

It is unpopular since the stock wheels are 18x8, and a 0.5" increase in width is marginal. Most go with a 9" or 9.5" wide wheel as it will be a noticeable increase in width.

Also a 255/40R18 is at the maximum width that a 8.5" wheel can handle. A 245/40R18 would fit a little better in my opinion.

If you are set on using that size, you can run a wide range of offsets. Anywhere from +50 to +30. +30 would be the farthest outboard, and +50 is the stock offset.

So if i step up the width to a 9" how much will that restrict the offset range. If i wanted to run the same wheels F/R. This would give me the ability to go up to a 265 width from what i have read. That is probably as wide as i would want to go due to wheels start to become heavy and you need to cash in your 401K to buy a set that will be lighter than stock lol. Which is one of my goals.

Thanks for the input!

If you go with a 18x9 and 265/35R18 tires, then I would suggest to stay within +35 to +50 offset. Again, the +35 will be the farther outboard option. What is the best depends on what your end goals are. Track setup? Autocross? Just a daily driver that you want to improve looks?

Also, a 265/35 tire on the street is really overkill, and you won't benefit unless you also do track days or autocross. I am currently running a set of 18x9 +45 with 265/35R18 tires for my summer setup, but I also do autocross and track days.

A 245/40R18 tire size is just about perfect for street use.

Yeah I "intend" to track the car a few times a year; when my job lets me have time off, but still a-lot of spirited back road rides ;). What I am currently doing is getting the car ready for the track. After the wheels; I have a bent one from an unavoidable Pittsburgh pothole, so their first. Next will be a suspension upgrade and then the cat delete mid-pipe and a Borla cat back. I don't want to go crazy, I to go with a look that makes the car look like it would if the factory made a performance model.

Sticky 245/40 on an 18x9 +40

Also keep in mind that tire compound will have a larger effect on track ability than size will.

For example, a 265/35R18 all-season tire will have worse grip than a 245/40R18 extreme performance summer tire (assuming same wheels/suspension).

Enkei RP-F1 is a good wheel choice that might give you that "performance factory" look. Plus they are the best bang for the buck in terms of weight/cost.

Well ideally, you'll want to have about a 10.5" wide rim, paired with, say, a 225/40 tire, along with some 75mm wheel spacers to make those wheels stick way out there all sexy-like. This famous method was pioneered and is aggressively advocated by an RX8-owner from Texas who applied it to his own car in order to increase the handling and 0-60 time. Said legendary vehicle is pictured below.
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That's a sexy ride there, he must own the local auto X seen :rolleyes:

Sarcasm off

Thanks for the help guys, I have pretty much decided to go with my original specs and a +45 to +48 offset wheel. I think its a good balance for what i want to do. As for the exact wheel, to be determined, just not RPF1, I know their popular I have seen them come up in threads a-lot but I just don't like how they look. If looks were not an issue, one stock replacement would do the trick.

Yeah, I don't like the way the RPF1 look either. I think the RP03 are available for similar sizes/weights/cost but they look much nicer IMHO.

245/40 instead of 255/40 though. 8.5" instead of 9" isn't a huge deal. I don't know why you wouldn't go 9" but whatever.

I also think there is more availability for wheels in a 9" width than compared to 8.5

I agree on 245/40

So i ordered a set of 4 TSW Nurburgring 18x8.5's ET45 in matte bronze. I considered the 9" width version but the offered offsets were at the edge of what would fit and i didn't want to take the risk so i played it safe. sorry if i offended any one there. My goals were to get in spec for the 255/40/R18 tires that i already had; got a ludicrously good price on them in the fall, remove some rotational mass, and add some style. Hopefully I will have pics to post later this weekend if the Pittsburgh weather holds out!

I'll be surprised if you removed any rotational mass. Just being honest

Will it fit?
 

volk TE37SL
18 x 9.5 +40mm

265/35/R18 all around

Will it fit? Any rubbing issues? Can I go wider?

Running adjustable coil overs with the possibility of upgrading to a 6 pot bbk in the future

Many thanks

Found on a site that a 18x8.5 nurburgring wheel is 19.5 lbs (although not sure if it is a reliable number). If true, they are lighter than I expected, but still not all that light. I have personally weighed stock 2005 shinka wheels at 21.5 lbs and a 2004 stock wheels at 22.2 lbs.

Weight increase from the larger tire probably makes that up plus it's weight that is even further from the hub. A wash at best

Plus the larger than optimal diameter of a 255/40 tire. Slower acceleration due to gear disadvantage.

So, never said i was expecting to be lighter than stock ;). I was expecting to get back to about stock weight. I only said "drop some rotational mas". More of us Rx8 guys should check out TSW, thire Rotary forging process is impressive. it saves all the weight on the outermost portions of the wheel, which is Best case. The interlargos wheel is in the 18lb range of the 18" range. Ohh i wheighed my gen one wheels when i refinnished them. 22.3lbs - 22.0lbs each. As for the tire size if I remember correctly it is less than a 1% change from stock height. I challange any one to notice. Heck 1% is within the change that will occure from tread wear......


Ninja edit; the 255/40/R18 is .23% taler than stock. I am willing to bet thats with in the margin of error for manufacturing.

I wasn't arguing that a 255/40R18 would have a gearing disadvantage compared to stock.....I was comparing to the suggested 245/40R18 size.

I looked at TSW when I picked out my wheels, and I found them pricey compared to other options. The RP-F1's for example are 2 pounds lighter and the same cost.

The Nurburgrings are nice looking wheels though, expecially in the bronze. I hope you like them when you get them on.

Thanks, yeah i would have gone with shorter tires but the price on the egle gt's was too good for suctch a small Difference. Ill have these torched at the end of the summer any ways :). Getting the wheels installed today. I weighed each one and they come at 19lbs +- .2 so lighter than speked by tsw.

Thanks for coming back with a weight on them. I am always curious about wheel weights.

18 x 8.5
+38

Not so much a will they fit question, Just looking for the ideal tire size for those size wheels? Just my car I use to get around town with no plans to lower, just wanting to improve the look of the car for the summer.

Thanks for the help in advance!