So right now, after lowering my car with s.techs my 17's are rubbing in the back. They have 40 series tires. I've got them on Craigslist FT and someone offered me a set of GSR fat fives + cash (dunno how much yet, in the middle of negotiations) The five's have 195/50/15's on them.

my question is: how much smaller will the 15's be when compared to my 17's? You think it'll still rub?

 

It looks like your 17s are 205/40/17s. If so, they are 23.45 inches tall. The 195/50/15s are 22.68 inches tall. My question is where are they rubbing? If they are rubbing on the side, you may be okay with wheel spacers. If they are rubbing on top, it may be because your car is too low for those tires/wheels.

 

they're rubbing right where the sidewall meets the tread. I'm thinking that extra inch of clearance will cut down on the rubbing except maybe in extreme cornering situations.

I'm thinking I should've gone with something a little stiffer than s techs....

and what do you mean "wheel spacers"? Should I just take it to a shop, have it aligned and tell them to give me more negative camber? I think the guy who installed my suspension also "corrected my camber" which has lead to all this rubbing B/S

 

When you run tires that are more than a little bit wider than stock, the inner sidewall may rub against the strut. Wheel spacers move the wheel and tire outward toward the fender (away from the suspension components). A 5mm spacer usually doesn't require that longer studs are needed but wider spacers do. If you go to the 15s you should be okay. My CX has 205/45/16s with Eibach Pros and there is no rubbing at all.
I would not change the camber if it means the tire will wear unevenly.

 

I think I'm gonna get some 15 inch slipstream look-alikes off of discounttiredirect.com

they seem to have pretty good prices. I checked out TireRack.com, but their wheel selection was ish IMO.

Even tho many people (ie, all of H-T) say that slipstreams are rip-offs and played out, I like the way they look. I plan on getting 15x6.5 bronze Drag slipstream look alikes with 195/55/15's. I really hope they don't rub.

This whole situation is really making me consider getting a stiffer set of springs after I pick up these wheels. I wouldn't mind if the stance was a smidge lower and a WHOLE LOT stiffer.

 

I bought my 16s from this place:
JLB Motorsports News & Events – WHEELS – Hot, Fresh New Styles from JLB Motorsports!

For some reason, their "products" page doesn't show up in my browser, any more but they did have great prices and a HUGE selection. Have you considered 16s in 205/45 size? There are more than a few that are under 16 lbs each and some come in colors that are not common.

 

how much smaller would the 205/45/16 be than the 205/40/17's that are on there now? I've considering going 16's, but am slightly worried they would still rub and also maybe still ride rough because there still isn't much sidewall...

edit- I'm on discounttiredirect.com now and looking at their tire selection.... They also have a 195/50/16, would it be smaller than the 205/45/16?

 

Here's how you calculate tire diameter:

[Width x (aspect ratio/100) x 2]/25.4 + wheel diameter

so the 205/45/16s are 23.26" tall and the 205/40/17s are 23.46" tall

I guess the 16s don't buy you a lot of clearance. The 195/50/16s are 23.67", so those would be even taller than what you have now. If you're going to keep your springs, you may have to go with the 15s.

 

I'm looking at a set of 16's tomorrow with 205/40's on them. I did the math and it came up to be about an inch smaller than the 17's I've got now. The same guy also has a set of 15's with 195/55's on them, but they're about the same size as the 17's I'm trying to get rid of.

I still think I may have to go to a stiffer spring. I'd also be willing to bet that alot of my problems could be solved by rolling my damn fender... but I'm a little nervous to try doing that myself...

 

Keep in mind that your speedometer will be reading a bit high if you get tires that are smaller in diameter than the OEM-sized tires. Part of the problem could be how low your springs drop your car. Your choices of tires are limited when you drop your car 2.5 inches or more.