Have you guys seen this article? article
The author makes a compeling argument that "A tall, narrow tire is superior for all off-highway surface conditions...". Looks like the 255/85 guys are onto something!
The Argument: A tall, narrow tire is a better choice for all off-highway surface conditions with the exception of soft sand, snow and soft mud that's depth exceeds 110% of the vehicles minimum ground clearance. Here is the explanation.
he even says this........
this article is very specific as to when a narrower tire would be best.
I just read the article. It's really interesting and helpful. Note that high flotation tires are the numeric sizes (33x12.5) not the LTs (285 75 16).
The 285 75 16, many of our tires, is an LT, not a high flotation, and is still within his recomended sizes for trucks that have a GVW of over 5 thousand lbs. (certainly my X does when it's weighed down with all my gear, recovery, camping, etc.) and which are used often on soft surfaces, also true for me in So. Cal. 285s are about 11.4" wide, nothing crazy. They do not have the flex/surface patch of high flotation tires.
In a sense, in the offroad world, and by this article's definition, 285 75 16s are still tall skinnys for some of us. They are within the realm of optimum by his standards.
But after reading the article, I do have a much better sense of why people are going for the 255s.
I love my 255/85s. Like others have said, a narrow tire is not better in ALL conditions, but in many. For me, I never wheel in sand, and although I like mud, I know I should avoid it, therefore the narrow tire works well for me. Where I am in PA is mainly rocky, so the added contact pressure is nice.
I have a frontier, not an X, but if the X stores the spare under the rear cargo area (the equivalent to under the bed in the fronty) then, Yes, a 255/85R16 will fit.
The reason I asked is because the 255/85's (MT) are listed as having a 33.3" diameter and the 285/75's (AT) have a 32.8" diameter. I've heard that the 285/75's will fit in the spare "hole", I just didn't know how tight of a fit they are.
For the record: "285" or "255" are millimeters. Alone, they do designate tread width. 285 mm is approximately 11.4", whatever the following numbers. To calculate diameter, the following numbers are essential.