Wheel Offset, Tire Sizes for Larger Wheels

[In-trepid]

I am looking at a number of different wheels. All are either 19- or 20-inch wheels. For those that have gone to the larger wheel sizes, what wheel width have you used successfully and what offset? What tires fit, what size rubs? Looking to narrow this down in the next couple of weeks. I am replacing the stock 18-inch Special wheels. Any help is appreciated even if you can only give part of the data requested. I'm sure with a few answers we can piece together what works and what doesn't.

[LUNAT1C]

I've had two styles of wheel and three tire sizes over the past 13.5 years, in addition to the factory Special wheel tucked away in my basement.

Summer 2009 - Temporary while factory set was attempting to be refinished (failed at that... but not important here)
Falken Torque 5 in Gunmetal - 18"x8"
245/45/18
No issues with rubbing. I don't recall the offset, but they did push out a bit from factory to fill the wheel wells on my previous '03 Grand Prix, and subsequently my Special while I was trying to refinish its factory wheels.

Fall 2009 until Spring 2013

SRT Design 20"x8", +24mm offset - 2008 300C SRT Design take offs
245/35/20

This is the size to maintain factory Special wheel/tire assembly diameter for proper speedo reading (and therefore odometer, if that matters to you).

Ride was certainly rougher, and I had a lot of issues with cracking and bending the wheels while driving on SE PA and SE MI roads. One particular moon crater on Mound Rd near the GM tech center in Warren as I took the I-696 exit almost made me miss my plane that morning, having to put the spare tire on, at the side of the busy morning commute interstate in Metro Detroit. Morning of fate maybe? Would have taken my Charger (factory 245/45/20, great ride) that morning if it wasn't in pieces from doing the front brakes that week. I decided 35 profile would never be on this car ever again. The damage from that pothole was severe enough to center-bend the wheel, making it irreparable. Luckily I had a fifth wheel since I bought a brand new during one of the cracked wheel episodes in PA. That bent wheel is still in my basement with my factory set.

Spring 2013-Present
SRT Design 20"x8", +24mm offset
245/40/20 - First Hankook Ventus V12, now Continental ExtremeContact Sport

Difference in ride is night and day. It's not "17" twin-six on touring struts/springs" buttery smooth, but it's much better than the 35 profile. If I remember right, I did put on the 18s once for reasons I can't recall, probably when the wheel was bent and I brought them in off the car for tire replacement right before Indy 2013, and they were still smoother riding (Michelins and Bridgestones in the factory size from the previous owner in 2008), but it's smooth enough now to be satisfied and enjoy the 20" aesthetic.

However, with 150+lbs of audio equipment plus all my show gear and our personal affects when we travel in the trunk and backseat, I get rub over railroad tracks and severe expansion joints. I-95 south of Philly and through Delaware, and some of the 2-lane highways through NC and SC are the worst for that. It's what has made me rethink lowering the car more than once, though I'm still looking on eBay for Eibach and H&R kits.

I suspect if I have the rear quarters rolled, it'll be fine. I had asked the body shop that repainted the car to do it, but they said the quarters were too thick and the paint would crack. I know others have done it, so I may still take the car to a custom shop local to me and have them do it professionally. The tires are barely kissing the edge, which shaves a tiny bit of rubber away.

The image in my signature is with the Continentals. I had them installed Spring 2018 after a pothole in Indy put a softball in one of my sidewalls, and a bad curb near John's house curbed a wheel. Went ahead and did all 4 tires after John raved about Continental, and both the M and Durango will get Continentals going forward!