I don't put a lot of miles on my jeep during the year so I can't tell you how many miles I have on the KM2s. But I did take a trip out to CO this summer with them. So I can give you more info from that trip and my current opinion on the tires.
Prior to my trip I discovered that my wheel bearings where showing excessive wear. So I replaced my bearings. As expected the bearings were part of the noise that I was hearing. I expect that is why my KM2s were similar in noise to my old STTs. I was hearing as much bearing noise as tire noise. With fresh bearings, the KM2s tire noise is really not a factor. At least with a Wrangler. I suspect the tire hum would be more noticeable in a more refined SUV. But it still wouldn't be considered noisy. Its a noticeable hum, but really subdued and to be expected from any aggressive tire.
I love the sidewalls. The tires ride great. I couldn't be happier with the ride and durability trade off of the sidewalls. I see people complaining about weak sidewalls on the BFG and asking for something stiffer and tougher. I sincerely hope that BFG does not listen to these people. The sidewalls ride perfect. I no longer have the sharp impacts that I was getting from all my other tires.
In regards to the size. One trade off of the narrow 255/85 is you do notice a little flex in the sidewall. It just doesn't have the width to support side loads as much as a wider tire. Its nothing concerning, but handling is a little different. Another trade off that I noticed is that due to the narrow tire, you do not have as much rim protection in the rocks. I had the misfortune of scratching up one of my new rims because the tire didn't extend beyond the rim. (Granted its possible my rim might have been damaged with a wide tire too. I don't know for certain, but I attribute the damage to the narrow tire not being any wider than the rim.) I am running my 255s on an 8" rim. A 7" rim would likely have better protection from the tire.
All in all I am very pleased with the tires. I know BFG seems to have a love them or hate them attitude from people on various forums. This was my first set of BFGs and I am quickly becoming a believer. I liked my Coopers, but my BFGs just seem to be a better tire. In particular the rubber compound is better. My Coopers always seam to weather check quickly, but I am not seeing that in my BFGs. Also the BFGs are giving me better ride characteristics.
So the big question. Would I buy these tire again? That depends. If I wanted a narrow mud tire. Absolutely. If I wanted a narrow and aggressive all terrain. Yep, I'd pick these over the STMAXX again. (Remember though my point of reference is from the STT and not the MAXX.) I plan to sipe them this winter and see how they do on the snow. That should eliminate one advantage I see in the STMAXX. However, if I wanted a quiet all terrain and was undecided on the width I wanted, I would really have to look at the BFG AT3. But if I knew I wanted an aggressive pizza cutter, this would be my choice again. In any event, I would certainly buy BFGs again.
One caveat I need to remind the reader is that I am coming from the perspective of a Jeep Wrangler. If I was putting these on a full size truck, I might be OK with the stiffer ride found in the Coopers.
