I went w/ her to order her some rims for her 98. I read on here that 17's are a really good choice, however, she wanted chrome "twisted 5 star" rims. The place we went to didn't have any that would fit. So she picked out a set and they are 18 X 8 Or 9 I cant remember. The tire size is P245/40/r18s (Z rated). I know most (or all) are against these rims but I just want to know how bad this will hurt street performance?

Since the overall diameter will be the same as stock will I need to upgrade the brakes (or brake pads)?

I am thinking of maybe pushing them out 1/4 of an inch. Would this be too much?

I think I can still drop the car in inch (maybe an inch and a half) good idea?

This set of questions is really more of a "street and appearance" kind of thread, than a road racing or autocross topic... So you probably won't find a lot of feedback here. With that said, here's a little info for you:

For street "performance", your stepmom probably won't notice a difference with 18's. A shorter sidewall makes it harder to put the power down quickly (depending on the power level and what your stepmom wants out of the car).

The shorter sidewall will "firm up" the street handling a bit.

And a shorter sidewall will make the small bumps and thumps more noticeable, because the sidewall normally takes up those a bit before the springs/shocks come into play.

You're right that if the overall diameter is the same, there won't be any extra load on the brakes.

I'm running 18 x 9 245's with no problems on the street. 245 was the max size I could run in STS class (but the 9" wheels were actually 1" too wide....)

Can't really answer the question about "pushing them out a 1/4" without knowing how they sit in the fenderwells. But as far as street driving on street tires, I don't think it would make a handling difference one way or the other, so it's probably not worth the effort.

Dropping the car is good ("generally speaking") for lowering the center of gravity for handling improvements. Is this something your stepmom cares about though, getting that little bit of lowered cg for street driving? It's good for appearance too, but it starts to cause problems with getting in and out of sloped driveways, speed bumps, etc. for street use. The ride can become harsher because of hitting the bump stops more easily.

So, when are you going to get your car out to an autocross?
(and then post up what you think about it!)

I have two fbodys, and I must have every tire and wheel combo imaginable for them, every thing from 16's to 18's in various widths and tire types. It really comes down to what her goals are with the car, but 18's are mostly for looks. Grip is worse, ride is bad, tires expensive. The odd thing is, 16's are probably the best all around. You get better traction, wheels are lighter, ride is better, tires cheaper. The tires for a 16 inch rim also run cooler because they have better heat dissapation with the greater sidewalls. Take a look at a race car of a similar size, like NASCAR; they are running 16" wheels.

A lowered car on 18's is going to ride pretty damn rough and scrape on everything; is that what she wants?

The shorter the sidewall (aspect ratio) the stiffer the sidewall needs to be to support load and resist rollover in corners. As a result, low aspect ratio tires are more susceptable to damage due to potholes and road hazards. They also transfer more force from pothole impacts to the rim. Often a pothole will damage both the sidewall and bend and aluminum or alloy rim. Talk to someone who works in a tire shop about how many low aspect tires are replaced due to sidewall issues.

Cal, the one problem I've seen with the 16" wheels... no clearance for big brake kits. That being said, I wouldn't go beyond a 17. I know you mentioned NASCAR, but I would assume they don't have as much of a problem with tire roll as autoxers would, do they? In that case, wouldn't a 17" wheel with a shorter sidewall tire help prevent tire roll?

Yeah I think allowing bigger brakes is the only advantage of bigger rims. But for "Mom's car" doubtful that will be an issue. Plus, LS1 12" rotors still fit under a 16" rim, and are pretty substantial brakes. You need to duct air into them for the big track anyway. AX isn't an issue because there isn't enough time for them to get hot.

For AX, you won't get tire sidewall roll over with good tires like Hoosier's on 16" rims, unless the front end doesn't have enough negative camber. I get zero roll over with 275/45-16 A3S04's. NASCAR runs tires with stiff sidewalls and adequate camber also.

Moved, please keep street posts in the General Discussion forum.