Well as everyone knows the bigger the wheels the harder they are to turn.So im wondering are seventeen inch rims the best compromise?I mean they wont be a huge difference from the 16s and they should help with handling a little more.As far as looks the eighteens look nice.But I wonder.Would 17 inch rims with the same tire size as the 16 fill up the wheel wells enough and be more practical.Hmm i think the tire size for the stock rims are 225/50 r 16 right? I hope someone can understand what the hell im talking about.If anyone is running 17 on theyre fd let me know and post some pics of your setup.

 

I think 18" are more for looks. 17" are lighter generally and give better performance IMO.

 

9.5 x 17, 47-50 mm offset--OR--9 x 17, 42-45 mm offset all around with 255/40-17. Best all around setup for stock style coil springs.

 

There's also the issue of tires. Since (irritatingly) not all brands are available in all sizes, in many instances you can use tires widths or aspects in 18" that you can't get in 17" for instance:

Big as you can likely go w/ 17" is 275/40/17. Theres no such thing as a 275/35/17.

In 18" you can use 275/35/18, 285/30/18, or 295/30/18 if you have the wheel width... and there are more front tire sizes to match, like 265/35/18, 255/35/18... very few tire makers make a 265/40/17... and if they do, maybe they don't make a 275/40/17

Theres just alot more flexibility in 18" sizes, probably because thats what most performance cars come with now (at the minimum)... the possible exception is with some R-compound tires that stiol come in laregely 17" sizes.

There are weight advantages with a 17" wheel, but if you look closely, you'll notice alot of 18" tires are actually lighter than their 17" counterparts of the same width. i'd rather have the outermost portion be as light as possible.

 

Thanx everyone for your input.From a physics standpoint the 17's wouldnt affect performance as much as 18's.The bigger the circumference of a wheel the harder it is to turn therefore the 18's would rob more power than the 17's.I was just thinking in terms of 17's being lighter possibly,also improving handling a little,and not robbing as much power.

 

I was looking at either running 17x8's on all corners or 17x8's in front and 17x9 in the back.Volk gt-7's.It all depends on how much width the c west bodykit adds to the rx 7's oem bodylines.

 

The circumference of an 18" wheel w/ tire is the same or less than that of a 17" wheel, because you use a lower-aspect ratio tire.

A 275/40/17 is roughly the same diameter as a 275/35/18.

A 285/30/18 is actually SMALLER than the stock 16" 225/50/16 diameter.

Like i say as well, often the extra wheel weight is offset by the tire weight... and its better to concentrate the weight towards the center.

If theres a performance advantage, it is because ultra-short sidewalls (like on a 285/30/18) actually don't have enough "give" for straight-ahead traction, and ride more stiffly.... but many people run 285/30/18 all around on the track where you don't have to do standing starts.

 

If I had to 18s, then I'd go 9.5 x 18, 48 to 50 mm offset with 265/35-18s all around (assuming stock style coil springs). Best compromise between sidewall height, width, and weight considerations...IMHO

 

I would assume the opposite. Can you show me some examples?

I found one on an m3 page:
Dunlop sp9000 205/50 17 11.7kg
Dunlop sp9000 225/40 18 10.7kg

Finding one instance of this does not make me a believer. Could just be a typo.

 

It isn't ALWAYS the case, but figure if everything else is the same, i.e: width and overall diameter, the 18" size has less sidewall, and potentially less rubber and weight.

Toyo T1S:
275/35/18: 25.6 lbs.
275/40/17: 27.6 lbs.

Bridgestone S03 PP:
265/40/17: 29 lbs
275/35/18: 29 lbs (and its wider)

 

I just think that the lower the profile tire the greater the chance of denting the **** out of the rim.So 17's with the same tire thickness as the 16's seem like a safer bet.

 

Iv'e seen alot of cars with 17's and 18's. I haven't really experienced the difference, but I think 17's would be better mainly because they have a smaller diameter than 18's with 30 or 35 series tires; therefore, you can lower the car more for better handling, and of course the weight. There are also two advantages with 18's(that I can think of) Bigger wheels = Bigger brakes = More stopping power(i think). The second advantage is there are more sizes in tires and wheels. Volk makes 10.5 inch rims for the back but only in 18" size. I would put 295's on the back and 265's or 275's on the front. I think that would work really well. In 17" sizes they make 10" wide wheels unless you get a custom wheel. 275's are the most I'd put on 10 inch wide wheels. But of course I lack experience in all of these aspects so these are just opinions.