I need to replace my stock 245's. Thinking about going to a 285/75/16. My setup is a 2500HD 6.0/4.10. Had this tire size on my 1500 5.3/4.10 a few years back and didn't like it because of the harsher ride and noticeable power loss. To me the 6.0 has more power than the 5.3. I tow heavy at times (20K+ GCWR) so I don't want to lose power. I don't care about looks, just want to gain some ground clearance. I'm for sure going to at least do a 265/75/16. Was wondering also if a 285/85/16 may not be the way to go to gain some height, but maybe less rolling resistance? Dunno. Let me know what you think.

If it were mine,I'd stick with just going to 265's.The unsprung weight is higher,ride much worse due to that. The 285's will sap your power,and torque more.Esp with a 6.0/4l80E,you've got a much (higher) first gear ration than a 5.3 4l60.Getting that big load moving will be noticeably harder,and places more load on the trans.

With 265s, you will gain a little bit of ground clearance, looks better, load ratings are higher, and the speedo will now be right on the money.

I personally like 285s better and have had them on all my personnal trucks for years, but a 265 is a better all around tire. As far as power loss, I had them on my 6.0L/4.10 setup and it pulled like a dream all the way up and over max GCVW, but I know it would of been better with 265s or stock 245s.

I'll probably stick with the 265's. I was doing some reading on the specs between 265 vs. 285 and there is only like 1.3" difference in height. Since I'm going to keep a stock rim it's probably better to stay with the 265 as well since I do occassionally tow heavy. Has anyone had experience with a 285/85/16?

I agree. 265's

http://www.intercotire.com/site41.php
This link will allow you to figure it out. You will have the same affect as changing the rear-end ratio. Depending on how often you tow that heavy as to wether I would change and I agree with a max of the 265.