I purchased some 39.5X16.5-15 Rockers. They come-up a little short for the diameter I had hoped for. Call them, they will give actual dimensions. All tires I know of and have had do come up short of advertised dimensions. Pitbull claimed a better ride on the street than other similar tires. They ride as good as the Bias ply Iroks I had though they flat spot within 4 hours and I would not recommend them for a daily driven vehicle (unless you will put up with the first few miles of driving through the flat spots). If I were to buy again I would probably size-up to get what I wanted (42 vs 39.5). Perhaps the 42's at an inch less in width would flat spot less as I could run more air pressure and still get a good contact pattern for wear. My experience is effected by the fact that they are mounted on 8" beadlocks which should be about a 9" wide rim. The manufacturer suggested a 10" wide rim.

I have not had them offroad, but have heard and read nothing but awsome comments about their trail abilities.

A few pics:

Next to my Irok spare on a 10": rim:
http://www.supermotors.net/getfile/674164/fullsize/dscn3492.jpg

http://www.supermotors.net/getfile/672811/fullsize/dscn3465.jpg

http://www.supermotors.net/getfile/672812/fullsize/dscn3466.jpg

http://www.supermotors.net/getfile/673668/fullsize/dscn3477.jpg

So I whined and complained about the size of the 39.5's, the owner of Pitbull made me a deal on 42's and found a local who wanted the 39.5's!!!!! Irok, 39.5X13.5-15, 20psi on 15X10 Rim Next to a 42X15-15 Rocker at the same pressure on a 15X9-15 beadlock. My son is holding tires at 90 lbs, 5"1" growing like a beanstalk and eating like a Bear!

http://www.supermotors.net/getfile/676535/fullsize/dscn3504.jpg

39.5X16.5-15 Rocker and a 42X15-15 Rocker both unmounted.
http://www.supermotors.net/getfile/676536/fullsize/dscn3506.jpg

Wow, finally looks like a little meat on the Carcass. These are measuring up to 41" on the 15X9" beadlocks and 40" on the rig (both measurements taken at 20lbs). The 39.5X16.5-15 measured 37" on the same rims and lost the same inch under load on the rig.
42X15-15's
http://www.supermotors.net/getfile/676767/fullsize/dscn3514.jpg


39.5X16.5-15's
http://www.supermotors.net/getfile/672812/fullsize/dscn3466.jpg

Now to get them out on a good trail.

dammit, now I want 42s, I have the 39.5s now and think they are too small as well

The 42s look sweet on your rig! Post up what you think of them off road. Im sure you will just add to the praise

I want to know how well your 5 bolt axle, assuming it's a D44 with chromo shafts? will hold up? I have a 72' EB that I would love to run a 38" tall tire but I have had too many issues with twisting alloy shafts and blowing Warn Premium hubs. All with a 35" Bogger.

Never mind, I pulled up your supermotors site and read.

Can you post a pic of the 42 on the vehicle from the front or rear? I am looking at the 42x15x20 when they become available.