Bill Lehman

To answer your second question, I've got -2.8 F running a Hoosier 265/35 x 19 and no rubbing at stock ride height or -10mm ride height.

Inrev

Must be caster then, at -2.6 I'm rubbing plenty. Ride height is apparently maxed out.

ExMB

Something seems amiss. I'm running -2.6 with Forgeline wheels, ET55 front on RE71s with no caster pucks with OEM corner balance and ride height and am not experiencing rubbing. Same went for the old MPSC2s.

ShakeNBake

Where's the rubbing?

(Front view)


With Shims


With Camber Plates


(Top Down View)


If you are rubbing on front fender liner, then you probably have too much caster from adding shims to get more negative camber and/or wheels with too little offset (lower ET)

If you are rubbing on the fender, then you probably have wheels with less offset (lower ET) and/or a lot of camber from shims. Running 19" wheels with a 35 series sidewall helps.

There is a lot of precision needed to dial in the alignment with more aggressive wheels widths/offsets. Rear especially.

Inrev

Car wash put some stuff on my wheels, it's easy to see where it has benn rubbing! I think it's too much caster because of shims.

ExMB

Wow. You definitely have an issue. Too many on here have similar alignments and I have as yet to see one as bad as yours on here. Something seems amiss here.

ShakeNBake

What wheels and offset are those? I suspect you are running something with too little ET.

Inrev

The standard Tirerack setup, offsets shouldn't be an issue.

ExMB

Don't count on tirerack being correct all of the time. There was a member on here who bought their recommended setup only to experience issues. Tirerack now no longer recommends that particular setup and took it off their list. I remember that track accusations were thrown about by a tirerack employee but in the end it was resolved with the member. IIRC those were a different brand wheel.

Inrev

interesting though I thought that was for the rear 11inch option. I will check. Right now my caster puck is set to middle, so once offset properly with the off-center hole and caster around 8.6-9 I will report back. Worst case some camber plates will probably fix the issue. Before shimming I was running -2 with these wheels without any issue

Inrev

Front Offset ET53
Rear offset ET40

orthojoe

I think it's an alignment issue. I know a guy that had zero problems with rubbing (over 3 degrees camber), but then brought the car in for adjustments and now his tires look just like yours.

ShakeNBake

The caster puck adjustment will fix the issue by getting the wheel centers in the fender (back towards passengers), but you will lose a lot of caster that gives you a negative camber boost when turning. I'm finding that camber plates are required to get both camber and caster in the right range for an aggressive alignment.

AutoQuest Motorsports

Great to see so many people enthusiastically tweaking the suspension tuning on their GT4! We've been doing the same, but took it to the next level co-developing a completely revised Multi-Link Rear Suspension with IMSA/Le Mans/Formula 1 engineer Jay O'Connell. Although it is technically available now and has transformed several GT4s already, the full forum release with all relevant information/data should be organized and posted in about two weeks....stay "tuned" and here is a little teaser

Hams955

Cool. Except, we're talking about the front.

- Chris.