I was wondering if anyone made a direct comparison on the track or street in a race or drag race. There is this discussion that 18" inch or bigger wheels will affect Straight line performance, maybe someone has a video where 2 S2000 with different wheel setups make a comparison to see how much of a difference there is?

 

The only factors at play between the performance of an 17" or 18" is the total package weight and handling attributes. Some people like to over think things. Where 18" are an asset is when more tire width/traction is desired beyond what's available in a 17" which those 17 are generally lighter in the same normal width options for our car. Also consider less sidewall in a 18 equals less sidewall deflection in equal constructed tires. For some that more precise feedback may be desired over road comfort and a bit more vagueness the added sidewall movement of the 17 provides. Take what I say as sound or don't and Continue to debate hypothetical and guess.

I suggest looking up the wheel and tire weight combined differences between the 17/18. Decide how wide a wheel/tire you want to run. As I've said before, if you are thinking of exceeding a 10"/255/40/17 package then look into the 10.5-11" 285/30-295/30/18 options. They can fit on the rear of an s with careful offset consideration and fender rolling.

 

Thanks for your input. I've driven several combinations on my various S2K's. Stock 16", Stock 17", Enkei RPF 17x9 all around 18" OZ Superleggereas and now 18" BBS LM's width street tires and semi slicks like the toyo r888. I noticed a decrease in braking and straight line performance, especially with the bbs since they are the heaviest combo. Cannot say that handling was affected in a bad way, i like the response with the 18" wheels. was just wondering if anyone made a side by side comparison, like a race where an s2k with 16" or 17" competes with one with 18" or hellaflush setup or something, just to see a difference if there is any on a straight line...

 

Doubtful there are many if any records of races to go on, even if there were, there is too many variables to throw off the outcome. It sounds like you have gathered your own personal info by running your various set ups coinciding with pretty much what's been said, so your experience is what's of value. Learn from it and continue to share it as opportunity comes up.

 

Car and Driver testing of 15" - 19" wheels/tires on a VW Golf:
http://www.caranddriver.com/features...d-tires-tested

Pretty impossible to do same/same comparisons over such a broad range of wheel diameters and aspect ratios, so this test falls short on a few points:
1. tire and wheel widths not the same:
195/65-15 on 15x6 vs. 205/55-16 on 16x7.5 vs. 225/45-17 on 17x8 vs. 225/40-18 on 18x8 vs. 235/35-19 on 19x8.5
Naturally wider wheels/tires will give a lateral grip advantage but with a slight increase in the weight disadvantage.
2. tire diameters are mostly close enough, except the 19" size is quite a bit taller than the rest at 25.5" vs. 25" (worse gearing further handicapping acceleration)
3. Different tire compounds. The 15", 16", and 17" tires are "High Performance All-Season" Eagle GT, V-rated, 440 treadwear, A traction rating. The 18" and 19" tires are "Ultra High Performance All-Season" Eagle GT, W-rated, 400 treadwear, AA traction rating. Obviously the latter are grippier tires (as seen in braking and skidpad results).

Any conclusions should be made with the above points in mind!

Long/short: the heaviest 19" setup (54 lb wheel/tire) was 2 tenths and 2mph slower in the 1/4 vs. the lightest-weight 15" setup (40 lb. wheel/tire), on a pretty slow car.
16.1 @ 86mph vs. 15.9 @ 88mph

18" (51 lb.) vs. 17" (48 lb) was only 1 tenth and 1mph difference: 16.1 @ 86mph vs. 16.0 @ 87mph.

Personally, I stick with the smallest diameter wheels I can that will fit over my brakes and allow me to use the tire widths I want, for a few reasons:
Weight (There are exceptions, but generally the larger-diameter wheel/tire combination will usually be a smidge heavier, with a higher polar moment)
Price (smaller-diameter = almost always cheaper for wheels and tires)
Aesthetics (not a fan of the look of super low profile tires, like a little more sidewall)

 

Really 17's are the best middle of the road option unless you want a wider tire than a 255. At that point 18's are a better choice due to there being a lot more tire options beyond the 255 size and there are more wheels that can actually use the tires (IE wider wheels). As long as you are keeping the wheel weight in mind and trying to stay below what the oem wheel weighs there shouldn't be that huge of a difference unless you are going with a very wide tire. Basically you should be trying to make up the added tire weight buy running a lighter wheel. Now with a wider tire you have more rolling resistance and grip so it is harder for the car to accelerate at the same rate but this negative is counter balanced by the added grip in a corner. I know I just repeated what the above guys said but yeah.

 

My SSR Comp 18 x 9 with a 255-35-18s Rs-3 tire weighs 2.5 lbs LESS per side then a REAR Ap1 wheel with OEM tire.

And 1lb lighter then a Rpf1 17x9 wheel with a 255-40-17 Rs-3 tire.

The SSR Comp weighs 17.0 lbs and the tire weighs 25 lbs. The 255-35-18 tire is actually 1lb lighter then the OEM Ap 1 and 2 rears.


Some people probably didnt know this. And assumed 18s are always heavier.

 

Yeah just depends on the manufacture of tire and wheel, generally 17" package is lighter. What’s the 17" equivalent of your exact wheel/tire package weigh?

RPf1 are light! Id be surprised if there was an 18" in anything of the same width that was lighter but if the tire is lighter, since that makes up the majority of the weight, it could happen. If I remember correctly a 17/9 rpf1 weighs 16.5lb.

I run a 17/11.5" rpf1 and it weighs 17.5lb. With the 295/35 the total package weighs 47. Pretty damn good considering the contact patch I get. The problem with this set up is it may become out of commission if Kuhmo doesn’t put that tire size back in production for their current XS replacement this year. I'm afraid I will have to step up to the next more available size of 315/35/17 if they do