Like Philip, I've also been looking (online only in my case) this winter for a new set of tires (incl. spare) for my TM. I am leaning toward Maxxis (M8008 Trailer Tire) based on reading here and elsewhere. I finally found the "specs" chart at maxxis.com at this specific link (I copied their chart below the link, hope it reads OK, if not, try the link):
http://www.maxxis.com/Industrial/Tra...ST-Radial.aspx
Part, Size, Ply, Diameter, Width, Max Load, Max PSI, Tread Depth Side Wall type
TL15712000 225/75R15 6 28.3 8.90 2,150 50 9/32 BSW
TL15710000 225/75R15 8 28.3 8.90 2,540 65 9/32 BSW
TL15711000 225/75R15 8 28.3 8.90 2,540 65 9/32 OWL
TL15713000 225/75R15 10 28.3 8.90 2,830 80 9/32 BSW
(Google says: BSW means "black sidewall" OWL means "outline white lettering". I did not know that.)
Notice they don't have a "D" or "E" rating anywhere on this chart, but this retail site does:
http://www.gripston.com/tires/TL15713000
It says the Maxxis "D" tire handles 2450 lbs. ($119. each) while the "E" tire handles up to 2830 lbs ($136. each) and the part numbers for their D & E tires correspond to the Maxxis chart for #2 and #4 in the chart. (These are higher prices than what Philip was quoted, but the price includes shipping...wonder where Philip got his prices?)
These prices are lower than what is shown at discounttire.com for Maxxis tires, "D" and "E" rated, at $134. and $157. respectively. However I've never heard of Gripston and I do know of Discount Tire (might even be able to pick up the tires at one of their stores in Denver sometime, 6 hours from here). DT asks site visitors to let them know of lower prices at other vendors, maybe they'll match if I email or call them this week.
I'm tentatively planning to buy online, have them shipped to my rural location, check those date codes, and have a local shop put them on the rims with those steel valve stems.
So...whatya think? 8-ply "D" or those 10-ply "E"? Is there any problem with 80lbs. of air in the TM 15-inch rims? E is probably going to give a little rougher ride at 80lbs, did I read somewhere that some folks run them at lower pressure? Maybe D will do since in my paranoia I'll probably inspect them every 10 miles...once I finally get on the road (for the first time) with my TM this spring!