Max tire size - 68 dart

SRT_DSTR15 said
Shoot was hoping to stay stock uppers and lowers hmmm. Good to know. I'll stay 255 then go 275 later

Stock lowers aren't a problem. The UCA's will be rim dependent. I know that on my Duster the 18x9's I have just touched the stock UCA and full steering lock and suspension extension. But there's a couple things going on there. Rim design will play a factor, and so will the size of the steering stops on the lower ball joints. After comparing a few it's pretty clear the tolerances aren't super tight on the steering stops, so, a smaller steering stop will mean more steering range to lock and less room for the rim. And alignment of course is in there too. I tested mine before I added the 3mm spacers to keep my tires from rubbing my frame at full lock.

So what I'm saying is that you have to check that clearance, but depending on your set up tubular UCA's might not be absolutely necessary. And there's always your comfort level too, the odds of you having the suspension fully unloaded while at full steering lock while actually driving are pretty darn small.

MuuMuu101 said
I'm still running the Michelin SS's. They're a decent tires, great on the road, but have their limitations on the autocross and road course (especially with 500+ hp). Once I lock down the fix for the tire rub issue, I'd like to switch tires. I'm thinking about offset shackles soon and if that's the case, I may even get new wheels so I have the same offset front and back so I can actually rotate tires. After this year, it's been pretty evident that I don't drive my car as much as I was projecting too during the build, so going down to a 200TW tire would also be in the cards with a 275/35/18.

And there's a few more options for tires in 275/35/18 too. I know on my car I'm pretty close to having the same offset front and rear, but the B-body rear axle, body style, and brake choices play a role there. My rims are actually a +35 in the front and a +38 in the rear, and I'd be better off with a +35 in the rear. The 13" brakes and a 3mm spacer make my front offset 27mm effectively if you compare to a stock 73+ disk set up. It's certainly doable with the right combination especially if you're willing to consider a small spacer to make up any difference.