So i am looking into getting new wheels and tires and i have finally decided on some jdm 18's all the way around. My question is, i think my stock type-s wheels weigh 24lbs, so how much do the 18's need to weigh to keep the same or better performance?
oh, btw, i am highly considering these wheels with 215/45/18 tires, plus either color matching the centers san marino red or gunmetal. OH YEAH..LOL
http://www.rbwheels.com/images/641aaa.jpg

 

OH, and i know they are 18x8f, 18x9r with a 45 offset, but i plan on negative camber and about a 2.5" drop

 

Why would you put wider wheels on the back of a FWD car? & why would you run rubber band tires in 215?

but to answer your question the rims would need to weigh the same to get even, & weigh less to gain anything.

 

well, first off, the wider wheels in the back is not what i really want, but thats how these are and secondly, i thought there was some kind of science to the whole upsizing wheels thing. if there is, then i would need to get like a 20lb 18inch wheel, for the same rotational mass or some shit. i dont damn know..lol..oh, and a 215/45/18 isnt wide, but i need it like that to have negative camber without rubbing and its the exact ratio as stock=215/50/17 - 25.6inch diameter

 

it's not necessarily about the total wheel weight, but in most circumstances you are correct and i am not sure about the math. BUT...you also must take into consideration the wheel design and where most of the weight is located - at the hub or farther out toward the rim to know how much the rotational mass will change. and i might be mistaken but couldn't you just buy two "front" rims for 18x8 all around, which would give you less rotational mass and better performance?

 

Yeah most places should sell you the 4 "front" rims.

 

those rims are fugly

 

you also have account for tire weight.

 

I shaved 12lbs per wheel when I had my SSR comps. 17X8 with 235-45-17's. I weighed the stock rims with the same 17" 235-45-17 tires. 38lbs vs 50lbs.
I found I had more traction problems. The CLS needs some wheel weight.

 

So true, and to tell you the truth on my behalf, I went from 19" wheels that weigh 25.4 lbs tto 18" wheels that weigh 16 lbs (about 9 lb difference between the two), and I felt no damn difference. Yeah the wheels were technically lighter, but the CL has a pretty strong engine, and needs some weight on the wheels to hook up, traction is an issue. Actually, the 19" wheels were alot easier to drive with because swithcing gears on my 6 speed with SC didn't have that herky jerky feeling when I switched gears at very low speeds. Maybe if you had a 4 banger with 120 hp, then a few lbs would make a difference, a small difference but who the hell is banking on that 1/100th of a second to the next traffic light.

 

18's didnt really make a difference, go for it