Widest tire for stock rims?
 

What is the widest tire that can be put on stock rear rims? I have read that the ZL1 size tires will rub but other people say they won't fit. I saw where one guy mixed front run flats with wider non run flats in the rear, but I'm not sure that is a good combo.
My goal is to have wider tires in the rear.

The widest you can probably go is the 295/35/20 which the Pilot Super Sports are offered in.

Just curious, can you put 275/35/20 all around?:popcorn:

305/35ZR20. We had a customer trade in his 2012 ZL1 that had Mickey Thompson ET Street S/S on the rear. He traded the car for a 2016 2SS in yellow and had us swap the tires over. No joke, they fit. They are def. on the snug side, but I didn't see any rubbing.

M/T 305/20 tires are recommended for a 10-12 inch wheel, they will fit your 9.5 stocker but that would be unsafe and potentially dangerous to do so.

So from what I can see, GM states the new SS 1LE will be running 285/30ZR20 up front and 305/30ZR2P rears. So stepping up to a 305 will fit inside your wheel wells, but that size is made to fit a 10.5-11.5" wide rim according to Michelin, Bridgestone and Pirelli. So I would say that your probably about the max tire width for a stock 9.5" wheel already. A 295/35R20 and 295/30R20 are quite a bit different in circumference from the stock 275/35R20, so unless you want to have the car reprogrammed for that size, so it doesn't mess with your speedometer and odometer, potentially mess with your ABS as well..... I think your best bet is a new set of wheels and tires to get the look you want.

When I had my 2010 SS I put 305 on the back with stock wheels. I had no problems. I would think it would be the same for the 16'. Also different manufacturers fit different within the same size.

8.5 rim 235-245 recommended 225 min and 255 max
9.5 rim 255-265 recommended 245 min and 275 max
That is info I've gotten over the net
This is why I'm putting 11.5 on the rear and 11.0 up front. I'll be running 285 305 respectively and be in the recommended width.
I don't really see a point to running larger tires than that unless you are really pushing the car at the track. I GUARANTEE I'll be able to hit 1.1 gs and when the hell is someone going to be using more than 1.1 on the street?

I wouldnt go more than 1 size up.

255 in front
285 in rear

You can. Just not with rear stock wheels on front. I tried. It doesn't work.

I'm running 255 for fronts and 285 for rears.
285 works fine. 295 may be pushing it a little.

Max and min Sizes for stock wheels. There are ways to go bigger but this is a o.e guide for front and rear that I would recommend to a customer before having them sign a disclaimer if it doesn't work.

By this chart moving up to a 255/40ZR20 up front, and the 285/35ZR20 in the rear that give you a near perfect overall height difference. As in it's the same difference front to rear, which should keep you from getting a wheel speed mismatch code set, and will allow the EBCM to function properly.

front is 245/40zr20 = 27.70, 255/40zr20 = 28.00. so that's a 0.30" difference

rear is 275/35zr20 = 27.56, 285/35zr20 = 27.87. that's a 0.31" difference

I was looking into this as well since I like my stock rims and don't want to upgrade as of now.

But if 285's in the back is the max I'm not sure it's worth it. Now, if I can put 295's then it'll be worth it.

Heck, I don't mind running 295's for the rear and leave the front to the stock 245's if possible.

In a perfect world for the most lateral grip on stock 20" rims, I say 295 and 255/275 would be ideal.