I'm copying this post that I wrote for another thread, as it is relevant here. It's essentially a review of my experience with the BFG Mud-Terrain KM2 in the 255/85/16 size. I've had them on my 2008 Tacoma for about three years. I hope someone finds my experience helpful.
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I run the BFG Mud-Terrain KM2 255/85/16 on my 2008 Tacoma, with stock steel rims like the kind that comes with the underbed spare. I absolutely love the tire because they provide additional clearance and I like the tall, skinny look. I've never actually used them in mud (who wants to clean up the mess?), but they perform extremely well in tough desert rock conditions at reduced pressures (<20 PSI). Though they are a "mud" tire, they're great performers on rock and have held up very well.
But there are downsides to this size tire, some of them significant. Some of the issues I've experienced are related to my particular tire (BFG Mud), but many come back to the fact that this is a very tall tire:
1) I wish I'd weighed my old tire/rim combination so I had a comparison, but I'd venture to say that my new BFG Mud setup is probably a third again heavier. Maybe more. They are very chunky tires, with lots of rubber. So if you want a lighter tire, the BFG Mud is not for you.
2) Climbing hills at highway speeds is a problem. This is a tall tire, and you'll soon recognize the need for a regear. Like, within the first five miles. I need to switch my gearing from 3.73s to 4.88s, which would address that issue, but that's a big expense that I haven't gotten around to yet. I only use my truck for trips, so its not like its something I have to deal with every day.
3) Towing capacity has decreased, based on the gearing issue noted above. Pulling a little utility trailer to the dump is fine, but anything more than that would be a no-go.
4) Braking ability took a hit. Safe braking distances have definitely increased, and I carefully keep my distance from vehicles in front of me. There's not much that can be done about that, and I'm not sure if that's a function of the increased weight (likely) or the larger diameter.
5) The BFG Mud is very noisy, especially when new. It's very noticeable, especially in the back seat where there is less sound deadening insulation. Folks back there have a hard time hearing conversations up front.
6) Fuel mileage. Tacomas have never been known for getting great mileage. With the stock tires and the usual list of modifications, I never broke 18 mpg. Now I'm down to about 14 mpg, which is clearly ridiculous, though it is admittedly self-inflicted. A regear would probably help that too, but there's no getting around the fact that I'll still be trying to turn a lot more weight.
7) The diameter is too large for the spare to fit in the stock underbed location. That is, unless you want to reroute your exhaust and do a bunch of other fabrication. $$$/PITA. As a result, I still have my stock spare under there, which isn't the end of the world, but its not ideal, either.
8) These tires will wear terribly if not rotated religiously and if proper alignment is not maintained. They just aren't as forgiving as a smaller tire when it comes to misalignment and infrequent rotation, and you really need to stay on top of it. I rotate mine at every oil change (5,000 miles), and get the wheels balanced and the front end aligned once per year. Doing that has kept the wear quite even. Four of these babies represents an investment of $1,000 to $1,200, depending on where you purchase, so spending $100 each year for an alignment and balance is a good investment.
So I'd advise approaching this particular tire and tire size with caution, as there are significant tradeoffs. Regardless of the tire brand you purchase, the 255/85/16 is a substantially taller tire, and the reduction in power and fuel economy is a real thing. Otherwise, they're great. Happy tire hunting.