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Trying to put together a wheel and tire package for my street / track RX8. Judging by my track experience with stock sized tires and rims, I came to the conclusion my RX8 is not going to pull a heavy tire. That's why I was going to stock to 245/40/18 squared. A small bump in section width and slight decrease in diameter seems about right. I know for track work 17s are better, but I prefer the look of 18s so plan on sticking with those. Searching for wheels, keeping cost and max weight in mind most options are in the 8.5-9.5 and +35-+40 range. Normally I would say the 8.5 is the way to go, however most wheels seem to have very little weight penalty going up to 9.5. Also I prefer the look of most 9.5 wheels as they have a concave profile. Surprisingly I see plenty of people running 245 on a 9.5" rim.
Is this stretched and what will the net effect be on grip? If I am running the 245/40, would the 8.5 or 9.5 be better for overall performance?
If I were just getting started with my rx8 and had to choose between a 17 and 18, I would personally recommend a 17x9 paired with a really nice 200tw or less 235/40 or 245/40 tire. Something like this below, there was also a magnesium offering as well. The smaller wheel / tire combo is ideal for n/a renesis rx8 imo and consumables will be cheaper as well.
Quote per Team in my 18x11 thread: 'This will provide some fairly big weight/MOI reductions that will definitely translate into acceleration gains plus the lateral grip rather than giving up acceleration to gain lateral grip.'
Now if aesthetics are the primary deciding factor, a 17x9 with 245/40 will be approx one inch lower in tire diameter to a 'comparable' set of 18's. If you have coilovers, you'll be able adjust ride height and alignment specs while dialing in your suspension.
Last edited by Federighi; 12-09-2021 at 12:42 PM.
Reason: typos
Only putting this here for the OP for examples of diminishing returns in cost depending on how much weight savings are desired and what brand you go with. Im comparing Motegi MR145 Traklite 3.0's to comparable Enkei RPF1 wheels.
MR145/RPF1
Size
17x8.5+35 / 17x8.5+30 ---- MR145 does not have a 17x9 size option.
Weight
18.49lbs / 16lbs ---- 17x9+35 RPF1 is supposed to weigh 15.9lbs
Price each
$191 / $257.50 ---- @ Fitment Industries. The 17x9+35 RPF1 are $266.50
2.49lbs lighter each for $66.50 each ($75.50 each for the 17x9+35)
-----------------------------------------------------------------------------------------
Size
18x9.5+35 / 18x9.5+38
Weight
21.36lbs / 18.6lbs
Price each
$232 / $355.50 ---- @ Fitment Industries
I think Weds Sport is another potential brand worth mentioning. They should have more than a few 'cost effective' options available imo and also earns you genuine jdm 'style' points in my book too. And, imo, Enkei's are everywhere and if I were to run one it would have to be from their RR line. I'm very particular about wheels, always have been, just a personal preference.
tc105X 17x9 +35 = approx 16.1 lbs. I personally really like the tc-X and is the sponsored wheel for LEG's WTAC vehicle (picture came out small for some reason?).
Speaking of weds, new forged tc105x model
http://wedssport.jp/products/english/tc105xforged.html
RPF1s 17*9 et45 with 235/45/17 fk510 is 5.5 lbs less weight in every corner than stock 18s.
Weds are top of the line but you can source rpf1s easier, imo.
you don’t want to pull a wide heavy tire/wheel combo, just a tall/heavier/more costly wheel/tire combo with more MOI and more engine loading to overcome over how several tenths of an inch radius might appear to all the people who aren’t looking and could care less?
So I would just like to point something out that I believe is an important deciding factor... What is your driver skill level? Let's be real for a minute about that subject. If you aren't driving at a skill level where you will be able to tell the difference between 2lbs per corner, you're better off putting your money down on more time behind the wheel than on wheels that you would be picking for the weight savings alone. If you aren't at that skill level yet, buy the wheels you want. Down the road if you reach that level and you are working to get every ounce of performance out of the car you can, then you can visit weight savings mods like lighter wheels.
Also, if let's say you have a budget of $1,500... you're better off picking $750 wheels and $750 tires than you are $1,200 wheels and $300 tires. You will benefit far more from good tires than lighter wheels. All your cumulative modifications and driving input mean nothing if you're sliding all over the place.
I have plenty of track time on two and four wheels. Experience? Substantial. Compared to some, maybe not to others. Is 2lbs a wheel something I would notice? Only if the 2lbs wasn’t evenly distributed. 😉
Is a 9.5 wheel an unnecessary performance penalty when using a 245/40/18?
I know people in the future would read that post, so i figured it would be a helpful point to make for future readers as well.
That said, you can find lightweight wheels in 18 diameter. As far as width, you can fit a 245 comfortably on a 8.5 wide. Going to 9.5 is a 12.5mm split for the sidewall/bead between the wheel and tire on the inner and outer sides. Thats not very much of a difference IMO, where as the weight (in your case) will make a difference. With a 9.5 you can always add more tire but that will increase your drag so a 245 thats better quality would be smarter purchase. You can split the difference and go with a 9 wide, but thats not needed. I would say just be flexible in searching for a 8.5w-9.5w with the weight you want within your budget. Different wheel styles will have different weights. Why not start with the wheel style you like, and then from there find the lightest offering of that style within your budget. Thats how I ended up on my MR145's. Are mine lighter than stock? Not really no.. did I get what I wanted for a good price? Yeah I believe i did. $1,450 got me the set in the 18x9.5+35 with the Federal 595RS-RR 245/40, mounted and balanced with aluminum valve stems (no tpms, i disabled my tpms system due to it giving me headaches).
Not the quietest tires, but offer good grip and I cant really hear them over my Rx8 anyways -insert turbo noises here-
I know people in the future would read that post, so i figured it would be a helpful point to make for future readers as well.
That said, you can find lightweight wheels in 18 diameter. As far as width, you can fit a 245 comfortably on a 8.5 wide. Going to 9.5 is a 12.5mm split for the sidewall/bead between the wheel and tire on the inner and outer sides. Thats not very much of a difference IMO, where as the weight (in your case) will make a difference. With a 9.5 you can always add more tire but that will increase your drag so a 245 thats better quality would be smarter purchase. You can split the difference and go with a 9 wide, but thats not needed. I would say just be flexible in searching for a 8.5w-9.5w with the weight you want within your budget. Different wheel styles will have different weights. Why not start with the wheel style you like, and then from there find the lightest offering of that style within your budget. Thats how I ended up on my MR145's. Are mine lighter than stock? Not really no.. did I get what I wanted for a good price? Yeah I believe i did. $1,450 got me the set in the 18x9.5+35 with the Federal 595RS-RR 245/40, mounted and balanced with aluminum valve stems (no tpms, i disabled my tpms system due to it giving me headaches).
Not the quietest tires, but offer good grip and I cant really hear them over my Rx8 anyways -insert turbo noises here-
appreciate the feedback. I will approach it like you described. I don’t want to get too caught up it weight specs, but know with a heavy, low powered car you don’t want to add any more to the corners than necessary. I remember going from some heavy firestone Indy’s to lighter bfg rivals on my s2k and picking up a few mph in the straight.
i have a few wheels on my list and the Tracklites are included. Reasonable quality, reasonable weight and reasonable cost. But something I like to look of.
Jumping onto an existing thread with same title I might have used. Just wanted to ask a few questions so I'm more confident placing an order.
First, I'm a daily driver, no track, and I don't consider myself an aggressive driver, not someone who will explore the limits of the car. Wanted to say that out front so it's understood that I'm the type that won't notice a few lbs. different on wheels or setup, and yes how it looks has a lot to do with my wheel choice. My 8 is stock. I do enjoy the look of wider wheels/tires to an extent but would like something that fits without having to roll.
I'm tired of the stock rims and they are dinged up a bit, am likely going to buy Enkei TSR-6 or TSP6 from their Tuning Series, like the looks and not as pricey as RPF1's. I plan to run 245/40-18 tires, haven't decided on what yet.
If I've read correctly in the Will it Fit thread and others, I can choose between 18x8.5 +38 or 18x9.5 +45. It sounds like the 8.5's are definitely a fit and that 9.5's will fit without looking too stretched.
Questions:
Am I right about the respective offsets for 8.5 and 9.5 to fit without rubbing on a stock car?
Am I taking any risk by going with 9.5's that the tires either will look too stretched or could cause issues on the wider rims?
I ran 18x8.5 +30 on 235/40's with great success on my daily driven s1 years ago. I also ran evoX BBS 18x8.5 +38 on 245/40's but didn't particularly like how they fit on the car at that time. 18x9 on 245/40 could be a good option as well imo.
I will say that if looking to maximize performance while also saving more than a few bucks in the long run, might I suggest dropping down to a 17.
Buying used is an excellent alternative to paying new wheel prices imo. GL
Thanks for the reply. It seems that Enkei doesn't offer many wheels in 9", mostly 8.5 or 9.5. I agree that 9" is probably the best answer but to be honest I get somewhat overwhelmed by the sheer number of brands and wheels available.
I think I prefer the look of 18" wheels over 17", really that's why I'm staying at that size, even having read of the several advantages of 17".
If there is another brand of wheels you think might be a good choice, please let me know.
Enkei, Weds, SSR and OZ are my 'go-to' budget friendly suggestions but it seems that the entry level price point on a set of 'brand name' wheels now falls between $800-1200 depending on spec, etc. At the very minimum you'll want to make sure they've been tested / verified to meet or exceed oem standards, etc.
If price is a large deciding factor, I'd personally suggest trying to find a used set locally available. It requires some patience but will def save a few bucks. Chance to find odd / rare sets too.
I've looked a bit online at Craigslist and Facebook marketplace, will look a bit more. I find that quite a few ads have the basics but not the details which makes me wonder if what I buy will actually fit. I realize I'll be spending over a grand on new wheels. I was looking at wheels for my Durango and it's just scary what they cost at this point, I ruined one wheel and the dealer said a single new wheel to match was $860, so I told them I'd just get a new or used set of 4 instead, am looking at used sets and think I'll come up with something.
Anyway, if I go with 9" wheels, will offset of +38-40 be the correct thing to look for? I assume +45 would push them too far in?
Here's an example. Saw these for sale for $600, here's the description:
"Got a set of enkie wheels 18x9 5x114.3 Tires are shot you will need new tires 600 obo Can deliver for extra"
From what I can see they are Enkei TS10's from their tuning series. A set of 4 is around $1050-1150 new depending on size. They are offered in 18 x 8.5 and 9.5, not 18x9 as said in the ad.
I will message the guy to get details but right away not sure what they really are.
18x9 and $600 obo sounds like a sweet deal to me! I imagine they were probably just a size that didn't sell as well as their 8.5 / 9.5 width offerings and were discontinued. I think those will look really nice on the 8 too!
Also remember it doesn't hurt to ask questions. I typically ask how many miles / any track days, production date, etc and inspect for any damages / cracks / bends, etc.
12-08-2021, 03:34 PM
