Tire size for 17/18...bit confused

[RStom - Hungary]

I'm looking for a set of new tires for my 17x8 & 18x10 Work CR-Kai sets. Before that I was calculating a bit regading the sizes and get confused.

1. The proper size:
I starteed with some calculation on the original OEM sizes:
The front
205/50 R15 586mm 0
225/35 R17 589mm +3mm
215/40 R17 604mm +18mm
235/40 R17 620mm +34mm
So from the above table it seems like that OEM NA2 size is not compatible with the NA1 size. The difference is +18mm which is more than 2,5%.
The rear
225/50 R16 631mm 0
255/40 R18 636mm +5mm
265/35 R18 643mm +12mm
275/35 R18 650mm +19mm
So from the above table it seems that the OEM NA2 size is compatible with the NA1 size. The difference is just +5mm which is much less than 2,5%.

Reading from the topics here wha tI have concluded is that lot of people use the following combos:
215/40 R17 front & 265/35 R18 rear
This setup seems to me that is not compatible with the OEM NA1 diameters as they are both of them bigger, but in % the diffenece is close to each other.

The other setup is
235/40 R17 front & 275/35 R18 rear
This setup seems to me NOT COMPATIBLE at all. The difference in the front is +34mm which is too much, and the rear is only +19mm. So in % the diffence between the rear and the front is too much.

WHICH SETUP DO YOU SUGGEST?
ISN'T THE SECOND SETUP SQRUING UP THE TCS??

2. Choosing the tires I have found the followings:
215/40 R17 & 265/35 R18 combos
215/40 R17
Continental Extreme contactDW 132USD 340AA
Falken Azenis RT-615-K 145USD 200AA
Yoko Advan Noeva AD08 184USD 180AA

265/35 R18
Nitto NT-05 218USD 200AA
Continental Extreme contactDW 242USD 340AA
Yoko Advan Noeva AD08 282USD 180AA
Falken Azenis RT-615-K 312USD 200AA

235/40 R17 & 275/35 R18 combos
235/40 R17
Nitto NT-05 143USD 200AA
Falken Azenis RT-615-K 175USD 200AA
Yoko Advan Noeva AD08 196USD 180AA

275/35 R18
Nitto NT-05 220USD 200AA
Continental Extreme contactDW 256USD 340AA
Falken Azenis RT-615-K 299USD 200AA

I drive the car about 3-5,000 miles a year, with -2,2 & -3,2 camber in the front&rear. For the track I use slick tires, so these are only for street driving, where I do not drive fast at all...

WHICH COMBO DO YOU SUGGEST?

Thanks guys

 

[Hapa88]

I'm currently running Dunlop Z1 Star Specs in 215/40-17 & 265/35-18 with zero issues.
Excellent tire, extremely sticky.... though tread life, cabin noise and hydroplane resistance suffer.

My size suggestions for 17/18 combos are
215/40-17 front
255/35-18 rear OR 265/35-18 rear

The 215/40 R17 & 265/35 R18 combo would be the most preferable for a 17x8 & 18x10 rim.

Other tires you missed for 215/40 R17 & 265/35 R18 combos are:
Dunlop Direzza Sport Z1 Star Spec
Yokohama ADVAN Neova AD08
Continental ContiSportContact 3
Kumho Ecsta LE Sport
BFGoodrich g-Force T/A KDW 2
Fuzion ZRi
Sumitomo HTR Z II
Kumho Ecsta ASX (All Season)

 

[nsxtasy]

My size suggestions for 17/18 combos are
215/40-17 front
255/35-18 rear OR 265/35-18 rear

265/35-18 is better for the TCS on the '91-93 NSX which came from the factory with 15"/16" wheels. 255/35-18 is better for the TCS on the '94-05 NSX which came with larger wheels, although the chances are less that it's going to be an issue with either size on these later cars.

Also, as Hapa88 notes, 265/35-18 is a bit better fit on an 18x10 rear rim. 255/35-18 can be mounted on 18x10, but that's the maximum width for that size tire, so it may appear a bit stretched.

Since this is for street use and you already have a separate set of tires for the track, I recommend the Continental ExtremeContact DW, which will last a bit longer than the "extreme performance" tires (Yokohama AD08, Falken RT-615K, Dunlop Star Spec). I would not recommend tires with lower performance than these, and certainly not all-seasons unless you need to use them in winter conditions as well as warmer weather.

 

[sca037]

We run 215/40/17 and 275/35/18 Dunlop Direzza DZ101's on both our '92 NSX's.
No ABS issues on the stock one (the LoveFab car has an adjustible Tilton dual-master setup so ABS is deleted), and the 275/35/18's on the rear makes the speedos read pretty much spot-on.

Brian

 

[nsxtasy]

the 275/35/18's on the rear makes the speedos read pretty much spot-on.

It won't be as close as the other sizes, assuming the speedometer is accurate with stock-sized tires:

255/35-18 0.7 percent larger than stock
265/35-18 1.8 percent larger than stock
275/35-18 2.9 percent larger than stock

275/35-18 also makes your car accelerate slightly slower; it's like getting a taller final drive ratio.

Also, the NSX's handling seems to degrade somewhat as the stagger (difference in treadwidth front vs rear) increases above 50 mm.

275/35-18 is actually slightly better for the TCS than 265/35-18, because the 215/40-17 is so much larger in diameter than the stock 205/50-15 front, but it has all these other advantages. I think you're better off going no larger than 265/35-18 on a '91-93. But get whichever size you want; it's your car.

 

[RStom - Hungary]

Thanks for the recomendations. These are the info's I was looking for )

Any good idea where to buy tires through the web? It is much much more expensive here in Europe, and I can get a free transportation from the US

Thanks in advance guys...

 

[nsxtasy]

Any good idea where to buy tires through the web? It is much much more expensive here in Europe, and I can get a free transportation from the US

The Tire Rack is one of the biggest and best here in the States. I don't know whether they ship overseas but I suspect they would be more likely than other retailers to do so.

Other places in the States that sell tires on the internet for good prices include:

Discount Tire Direct
tires-easy.com
tiresavings.com

 

[Jin1976]

Hi,

What offset did you get for those wheels? I'm thinking of getting Work XT7 from our local vendor in the same sizes.

 

[Doraemon]

I'm currently running Dunlop Z1 Star Specs in 215/40-17 & 265/35-18 with zero issues.
Excellent tire, extremely sticky.... though tread life, cabin noise and hydroplane resistance suffer.

My size suggestions for 17/18 combos are
215/40-17 front
255/35-18 rear OR 265/35-18 rear

The 215/40 R17 & 265/35 R18 combo would be the most preferable for a 17x8 & 18x10 rim.

Other tires you missed for 215/40 R17 & 265/35 R18 combos are:
Dunlop Direzza Sport Z1 Star Spec
Yokohama ADVAN Neova AD08
Continental ContiSportContact 3
Kumho Ecsta LE Sport
BFGoodrich g-Force T/A KDW 2
Fuzion ZRi
Sumitomo HTR Z II
Kumho Ecsta ASX (All Season)

I second this setup. I have the same setup now too. I had 275 before and it just didn't look as right as 265. I didn't feel that I was losing anything by getting smaller rear. This is the second set of Z1 and I love them..

 

[etang789]

I'm currently running Dunlop Z1 Star Specs in 215/40-17 & 265/35-18 with zero issues.
Excellent tire, extremely sticky.... though tread life, cabin noise and hydroplane resistance suffer.

My size suggestions for 17/18 combos are
215/40-17 front
255/35-18 rear OR 265/35-18 rear

The 215/40 R17 & 265/35 R18 combo would be the most preferable for a 17x8 & 18x10 rim.

Other tires you missed for 215/40 R17 & 265/35 R18 combos are:
Dunlop Direzza Sport Z1 Star Spec
Yokohama ADVAN Neova AD08
Continental ContiSportContact 3
Kumho Ecsta LE Sport
BFGoodrich g-Force T/A KDW 2
Fuzion ZRi
Sumitomo HTR Z II
Kumho Ecsta ASX (All Season)

For the tire size 215/40 R17 & 265/35 R18 combo there's also

Federal 595RS-R

Their website
http://www.federaltire.com/en/html/pdetail.php?DB=motosports&pdline=3&ID=3

Reviews
http://www.s2ki.com/s2000/topic/839178-hankook-rs-3-vs-dunlop-z1ss-vs-federal-595-rs-r-vs-bridgestone-re-11/

 

[etang789]

Correct me if Im wrong

I also see that Bridgestone Potenza RE-11 have our sizes in 215/40 R17 front & 265/35 R18 rear.

http://bridgestone.co.jp/personal/tire/potenza/re_11/size.html

 

[Nero Tenebre]

Are star specs far superior to BFG kdw2's?

 

[Hapa88]

Are star specs far superior to BFG kdw2's?

YES, they are FAR superior in the dry. Possibly in light rain too.

Dunlop Star Spec is an Extreme Performance Category Tire. The BFG KDW2 is two levels down in the Ultra High Performance Category (in between is the "Max Performance Category").

http://www.tirerack.com/tires/types/tiretype.jsp

Extreme Performance Summer
You want extreme dry street performance and are willing to trade some comfort and hydroplaning resistance to get it.

Max Performance Summer
You want an unsurpassed blend of dry and wet street traction and handling and only the finest will do.

Ultra High Performance Summer
You want an outstanding blend of dry and wet street traction and handling.

High Performance Summer
You want a good blend of dry and wet street performance when "re-tiring" your sports coupe or sedan.

Grand Touring Summer
You want a good blend of dry and wet street performance along with responsive handling and noise and ride comfort.

Track & Competition DOT
You want D.O.T.-legal street tires for autocross, racetrack or rally performance.

 

[Hapa88]

Correct me if Im wrong

I also see that Bridgestone Potenza RE-11 have our sizes in 215/40 R17 front & 265/35 R18 rear.

http://bridgestone.co.jp/personal/tire/potenza/re_11/size.html

You are correct, however the 215/40 R17 is not available in the US at this time (the 265/35 R18 is available though)

http://www.bridgestonetire.com/productdetails/TireSubBrand/Potenza_RE-11

 

[etang789]

You are correct, however the 215/40 R17 is not available in the US at this time (the 265/35 R18 is available though)

http://www.bridgestonetire.com/productdetails/TireSubBrand/Potenza_RE-11

Ah thanks for the clarification ...

 

[Nero Tenebre]

Who has pictures of a 265/35/18 tire mounted on a 10" wheel? Is it stretched?

HAPA,
How much better in percentage, in your opinion, is the star spec? I was discussing this with Osiris, and he makes some good points:

-Both last about the same mileage
-Star Specs stickier initially
-BFG KDW2 better in the wet
-KDW2 will perform at 8.5/10ths for 10k miles
-Star Specs will perform at 10/10ths for 5k miles then at 6-7/10ths for remainder of life
-Both have stiff sidewalls for crisp turn-in
-Star specs are heavier (32lbs for 275/35/18 vs 28lbs for same size in KDW2). 4lbs is a lot of additional unsprung mass at each corner.
-Star specs take longer to warm up to maximum grip (?)

I read about how "today's extreme performance tires are like yesterday's R compound tires in grip but last far longer" and I thought wow, they invented some new compound so consumers can have the best of both worlds. Then, I thought about how the Star Specs wear and realized they are just up to their old shady tricks. Star Specs seem like touring tires wrapped in R compound, meaning their life is extended only by the fact that the crappy compound is long lasting but the sticky compound wears out quick. If you want extreme performance then you would really be replacing them at that point, not when the tread indicators say so- which is a hidden cost.

I think I may stick with the KDW2 even if their performance is 15% worse (95% street use, occasional track day)... Now if they were 30% worse, maybe it would be the star specs. I wish tire manufacturers would put some hard numbers to their classes instead of those BS descriptions of their target market demographics. I definitely like the look of the KDW2 better as it is my all time favorite tread design so it's just as well.

Did I miss anything on the comparison?

 

[Hapa88]

The only thing I can lead you to is the Tirerack.com comparison tests.

I'm not sure if the numbers used in the reviews are standardized test to test(they appear to be by glancing at them), but you can get a rough idea of the performance differences by looking at the numbers.

The Dunlop Star Spec had an overall score of 7.79 (combined dry & wet), the KDW2 had a score of 6.94.

Keep in mind the tire sizes were the same at 225/45/17, however the cars were slightly different 2008 BMW E90 325i Coupe vs 2008 BMW E92 328i Coupe (and so were the test days).


Extreme Performance Summer Tires Comparison
http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=118

Ultra High Performance Summer Tires Comparison
http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=104

I am currently on my first set of Star Specs and have tracked the car a number of times with them. Rears are at the wear bars, and the fronts still have plenty of tread. I would disagree with the statement "Star Specs will perform at 10/10ths for 5k miles then at 6-7/10ths for remainder of life" so far. I think they are at least 8/10ths if not more at the end of life (also I don't think my rears have lasted 5k miles.. then again I have the 1991 spec rear toe and these tires are my track set).

 

[Nero Tenebre]

Thanks HAPA, can I see what the 265/35/18 looks like on the 18x10? I think I am going to go with 275/35/18 bc I think the 265 will be too stretched.

 

[Hapa88]

This is a 265/35/18 Dunlop Star Spec on an 18x9.5" wheel. Imagine the rim sticking out .25" with the tire remaining in the same place and you can get an idea.

 

[MR-DREAM]

Please help with any advice !

I have 18' Khumos F/R on my 98 NSX. I'm not sure of the profile. My grip is good in dry conditions but aweful in the least bit of rain! The tires have 10k miles on them but almost full tread. The car will slide out on me at speeds under 20 mph?! (under low acceleration in rain) .Any advice would be much appreciated.

Thanks

 

[angus]

Thanks HAPA, can I see what the 265/35/18 looks like on the 18x10? I think I am going to go with 275/35/18 bc I think the 265 will be too stretched.

265/35/18 on a 10" rim has basically no stretch.

 

[N Spec]

Please help with any advice !

I have 18' Khumos F/R on my 98 NSX. I'm not sure of the profile. My grip is good in dry conditions but aweful in the least bit of rain! The tires have 10k miles on them but almost full tread. The car will slide out on me at speeds under 20 mph?! (under low acceleration in rain) .Any advice would be much appreciated.

Thanks

I would check the inside wear of your rears which is normally concealed. 10K miles usually would be the turning point for replacing the rear tread for many of our cars. Also the model/type of tire you have also comes into play.

 

[Hapa88]

I would check the inside wear of your rears which is normally concealed. 10K miles usually would be the turning point for replacing the rear tread for many of our cars. Also the model/type of tire you have also comes into play.

+1!
10k miles on the rears should be down to the cords on almost any tire for the NSX (if you have the correct alignment specs)!!

 

[etang789]

Just ordered a set of RE11

Front: 215/40 R17
Rear: 265/35 R18

 

[TURBO2GO]

I am thinking I might like to run R888s or nitto nt01's, both are 235/40/17 only. To match the ratio of my stock tcs the perfect rear size for that is 275/35/18 rears.

Question is... How much will a 235 rub? Can you get it to not rub at all by a particular wheel width and offset or suspension height? I've read conflicting info on this.