Here is what i found when researching for my J5 track belting purchase. This belting is not that uncommon or hard to get. The problem is to find a supplier that has some in stock that he can cut to your spec. Tracked vehicle part suppliers have belting but charge more than conveyor belting suppliers. The belting specs. I asked for are temp rating -40 deg F, stretch percent .08%, smallest work radius, number of plys 4, cover thickness 1/16 X 1/4" and overall thickness less or equal too 5/8" thick. I ended up buying from a local business in Fairbanks who found a supplier in Washington that had Goodyear "Plylon Plus" 4 ply 500 in stock. I was able to purchase 80' X 5.5" through them for about $900 delivered to Fairbanks which is allot less than other quotes i got. But I have no experience yet with this product so i dont know how good it is. Burt the sales guy assured me it is the right material and has sold it for this application many times for years. See the attached belting spec sheet for his contact and specs and Let me know what you think.