Alright guys I don't like to start threads on topics that have already been discussed in detail, but I've been reading through information for several hours and I can't be sure what's opinion, what's been tested, etc. So I'm planning to upgrade rims and tires all at once in a while, hopefully before my second round of auto-x.

Just to lay it out, I drive fairly aggressively... I prefer handling over noise, comfort, etc. but I would like to gain acceleration as well. My car is stock height but I'd like to leave the opportunity of lowering it open for the future. I have already made up my mind to go with 17" rims because I think that if I get the right rims, I can make up for the gain in rotational mass with the decrease in overall unsprung mass and still gain a bit of acceleration. Another big reason is so that I can afford a shorter sidewall because I'm really big on handling and I couldn't care less about ride roughness. If people don't like it, they can go get another ride.

So... If I run 215/40/17, which seems to be tried and true even with lowered cars, what rim width would you recommend: 7" or 7.5"? Both will work with most 215/40/17 tires I'm considering, but which would be better for handling? Obviously 7" will lose some unsprung weight, but will it affect the sidewall firmness and roll?

Also, offset. Everything from +45mm to +42mm seems to be confirmed and I don't want to delve into uncertain territory with +40mm and push it too close in case I want to lower later or what have you. So is more or less better in this case? I would like it to be close to lining up with the body panels, but if a different offset will offer improved handling, I'll take that instead.

Oh also, what are the true advantages and disadvantages of wider tires? I know that the common belief that wider = more grip isn't proportionately true, but what does this mean on this setting? I read in a source that went into a fair amount of detail on the subject that in essence and that I find reputable, that the amount of surface area at any point is directly dependant to and dictated by the load bearing on that specific corner. In other words, with a constant static load (not changing the weight pushing down on a corner, i.e. the car), the surface area is a constant, regardless of tire width. Of course increasing tire width will lead to a wider contact patch, but will be compensated by a decrease in length of the contact patch. So does this matter when you're talking about an extra 10mm? I guess the only major factor would be steering. Responsive, quick steering and turn-in is one of the key features of the RA in my head, and I definitely don't want to sacrifice this. For those with 215mm wide tires and decently light 17" rims, would you call the difference noticeable?

By the way, I have a little tire height calculator that I hosted on the only FTP I have access to at this point: http://fasce.com/tmp/calc.html if anybody is curious.

Thanks a lot for any input you guys can give.

 

I run 215/40/17 (Nitto Neo) with a 42mm offset (5Zigen FN01R-C 17x7) with my car lowered 1" on Tein Basics, and have NO rubbing issues whatsoever. I probably could have gone with a 7.5 width, but I didn't want to run anything lower profile than a 40 series, especially since my car already is pretty stiff with the Teins.

 

Alright thanks for the feedback... I found out today that I probably won't be getting rims 'cause I just got a $380 ticket in the mail for running a red at a right-hand turn. Now which is more worth it... having nice rims forever, or being 30 seconds less late to class. Wow I'm really pissed.

I have about $6k but I'm a cheap a$$ so I doubt I'll be getting rims. Shoot if I spent whatever I had at the time, I would have a turbo right now. But in case I do get rims, I would appreciate any more feedback. And thanks again reTro.

 

I run 215-45-17 on 5zigen 43offset 17" x 7.5 no rubb.

 

Thanks thunder.