[Millertime555]

Hey guys, I'm currently running Goodyear Eagle F1 Supercar 3s for autocross (285 front and 305 rear). They're currently my best option because I have 20" wheels.
My question is this: Are the Falken RT660s (or another 200tw like A052s) a large enough step up in grip to make the change? I'd have to downsize to 19" wheels to do it.
Thanks!

[Msquared]

Short answer: yes. I mean, "worth it" means different things to different people, but the 660s are probably about 1 second faster on a 60-second course. They also might actually last longer for autocross-only use (but not track use). However, they are no longer the fastest tire for autocross use. The Bridgestone RE71RS is faster, and you can use the 285/35/19 on a 19x10 or 19x11. Not sure what class you are running, but it appears to allow non-stock wheel widths and diameters since stock non-1LE SS wheels are not wide enough to effectively use the tire sizes you mentioned. So if you are unlimited in wheel sizes, you might consider 18x11 front and rear and the Bridgestone in 295/35/18.

[DaveC113]

Agree 100% with Matt, 295/25/18 RE71RS are the way to go if you're buying right now. Yok A052 have been hard to get and are about $500/set more than REs. RT660 are a bit behind, hard to say exactly how much, but enough it's noticeable, and they need a lot more heat than the REs. Nankang CRS might be out soon in ZLE sizes with a new compound soon, so IDK, maybe they'll be the new hot tire when they get here.

The top CAMC guys are on REs, but I was within .5s of 1st yesterday running 660s, and historically, I rarely do much better against the winner when he was on 660s. Some guys in AS with Caymans/Boxsters, and the STX FRS/BRZ's are flying on them though. I'm going to wait and see what happens with the CRS since I have ZLE sized wheels, and there's always hope Bridgestone will start offering larger sizes too... meanwhile the Falkens may be a disadvantage, oh well. If you want the most options, I think 18x11 square is your best bet.

SC3 need to be much hotter than autoX tires, so IME grip depends heavily on the weather. 100F, full-sun, and an event with 6 runs would get you a few good runs with about that 1s disadvantage. Cool weather, multiple seconds... the tires are really bad when it's cool out!

[enzia35]

Downsize the wheels, lose some weight also! Win-win.

[Millertime555]

Thank you for the replies! A couple of follow up questions: Which offset do you guys go with for the 18x11s? I have a non-1LE, so I'd be concerned about the body roll making my fenders rub on any tires that stick out (happened once to me with rear tires that stuck out).

Second question: Did you guys notice a big jump in oversteer when switching to a square setup? I saw a guy on another forum mention that he gained too much oversteer by switching to a square setup, causing him to be more prone to spinning.

[DaveC113]

Downsides of square setup is more oversteer, but the car really needs a much stiffer front roll bar anyways. Also more ice-mode brake incidents which is a major issue for pre '19 SS non-1LE cars. I got a '19+ ABS module but you have to get lucky with that finding the right one from a wrecked car.

I went back to staggered from 19" square, but that was pre RE71RS, when RT660s in 315/305 on 19s was arguably the best tire for our cars besides A052 which were hard to get, expensive and fast-wearing.

Also gearing is a factor, I'd need 3rd in some courses running 18s.

But the REs are so dominant right now if you don't get 295/35/18 REs you're going to be slower vs other setups. I'm really hoping that changes with the new CRS and/or REs being offered in larger sizes, but that's wishful thinking with no facts behind it.

For 18x11 you want et35 and need a 1" spacer up front and longer wheel studs. Apex wheels has a fitment guide and all the parts. On sale right now for the J4th holiday... Doubt they'll hit your fenders.

[Msquared]

I'd defer to Dave on the offsets if he's done it. Those sound right to me based on SS 1LE and ZLE factory fitment. Since the 295/35/18 is a bit narrower than the 315s that most people use on those wheels, that will help keep it from poking out and having the fenders hit, too...as will the slightly smaller tire diameter than stock. FWIW, I have a local friend with an SS and he runs 19x11 with 305/30/19 front and rear, and he has zero issues with rubbing. ETA: His 19x11s also run 35mm and he's using a 20mm spacer in front. An 18" will need more spacer to clear the strut, so Dave's advice to use a 1" spacer (25mm) is spot on.

I think you'll pick up a bit more front grip relative to rear. That may or may not be something you want to correct. Since you don't have the slightly overeager eLSD on your non-1LE SS, your rear grip is probably calmer and you may find you don't need it. However, if you find you want more rear grip, than a Hotchkis adjustable front bar is an easy and fairly cheap mod.

[WhiteMale]

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