I want to fit the widest tire/wheel possible in the back. If i can fit a 335 back there i will. Basically there are 2 ways i can think of to add width:

1. widen the wheel..duh.
2. push the wheel out further so it can be wider and not hit the inner suspension/frame.

In a perfect world the car would be designed to accept all the width on the inside without having to push the tire out past the fender(viper, vette). But we dont enjoy that privilage. A few concerns...

It appears the first place the wheel/tire will hit as it moves inward is the frame(about 1" of clearance). IIRC its about 9'oclock on the wheel if your looking at the driver side, in the front part of the inner wheel well. I think it could be banged in with a hammer for more clearance without hurting anything. The next place of contact seems to be the strut itself.

My other idea is to not only widen the wheel but push it out further(lower offset). Will the wheel(now sticking out far) and rear quarter panel hit on a bump at highway speeds or around a hard turn? You see mustangs running around all the time with this setup but ive never looked closely at their fender. We have a huge gap and really stiff springs on our srt6's. I also dont mind rolling the lip in on the inside of the quarter panel but im talking about going so wide i think thats negligable.

Id really like to just keep and widen our factory rear wheels. They are 19x9. I can have up to 3" of width added for $250 each. Thats a 19x12
Question is to push the wheel out far enough ill need spacers. Ive never been big on the idea of spacers but i used them on my SRT4 at the track with no problems. What about welding them on the wheel to make it all one piece? For some reason the guys who widen the wheels recommended against spacers.

So what does everyone think about all this?

 

I've been autocrossing with a 15mm spacer (hubcentric, billet aluminum) in the rear for 2 seasons...not a problem, just make sure you get appropriately sized lugs.

 

I don't have experience with the xFire, but I run a wide setup on my F-Body. My setup used a wider offset, and my tires don't tuck inside the fender. This minimized my rubbing on the inner wheel wells. I was advised to roll the inner lip a little bit, otherwise the metal could cut my tire tread, but I tested before taking this route, just trying to drive aggressively and see if I was rubbing paint off the fender or cutting my tread. It appears to be completely fine, no missing paint, and no cut tread, and this is with a 0.75" drop. I also banged out the inner wheel wells just in case I could rub there, but no issues there either.

I would suggest using a wider offset, just because it's easier to roll the inner lip than try to troubleshoot rubbing on the inner wheel well, but it also matters whether you like the look or not. Mine barely peek out past the fender, but I've seen other cars (not performance cars) with the tires way out wide, and I personally don't like the look. It's up to you whether you can handle that.

BTW, does anybody make thicker sway bars for the xFire? I know they have them available for the MBs, but I'm not sure if we have the same suspension geometry (I don't think we do). That could help you out if you do end up rubbing, and I think that may be why I didn't have some of the problems other people did when going wide. More aggressive shocks would help as well.

 

What wider tires maintain the same height as the stockers to avoid throwing the speedo off?

 

don't know what the OP's plan is, but you could go smaller diameter wheel and have options

also: sorry, this is a bit OT, but is the speedo based on the rear or the front wheels? I've always kinda wondered, but never knew.

 

Very good question! I'm assuming that it is based off the transmission which means rear wheels for RWD and front for FWD. Let's see what the members have to say.

 

Thats a very good question you brought up about the speedo. Id like to know too.

My reasoning behind running the wide setup is based on a few reasons. I want maximum traction on a street tire so i can go to the track w/o swapping to slicks, as well as launch hard from a stoplight without loosing too much traction or having T/C bogging the car down. This means wider tread with a soft compound, but not so soft i cant drive 60mi to work and back daily. Im thinking something like a Nitto 555r or comparable. Also id be lieing if i didnt mention looks. There is nothing better than the rear view of a Viper or Vette with huge rollers. I dont want to make the car something its not but with the power i have available(and more soon to come) i dont think its a rediculous idea.

 

Good point, I usually expect the sensor to be at the rear end, but every car's different. Anyone know for the xF?

edit: damnit people type fast, lol.. I'm the fourth person to say the same thing... damn i can't count either, lol

 

Might this help?

https://www.crossfireforum.org/forum...ad.php?t=25349

Or this?

http://www.rims-n-tires.com/rt_specs.jsp

 

Tires with a low enough profile to clean out your bank acct... You'd probably be going 25 or lower profile at that width? Anybody know where that handy-dandy internet calculator is? I forgot the site, but I think it's a miata site...

edit: damnit i'm slow, again. Thx maxcichon!

 

If you're looking for pure performance, this is the way to go. 16 x 12 or 17 x 12 will be lighter, and tires will be cheaper too. Definitely not as badass-looking as wide 19's tho.

 

Maybe you can squeeze these babies on:

 

Talk about a 'fat boy'! You might have to roll your wheel well a little though.


MikeR

 

wow what is that thing? its half the size of the woman!

 

Those fatties would look good on the back of my stang for sure !!!!!

 

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I wanted to contribute, but now can't remember the numbers ....