First of all, track has been tightened. Lol
Well, 3602-137 is the part number for the 18 162
80 durometer is what it is marketed as.
My 14 is 2602-856, 153 also 80 durometer.
Sitting next to each other in the garage, the 18 paddles are much softer.
The 14 is harder because it's "age hardened ". I have a track off a 12 or 13 model, it's 85 durometer though, but it's so hard I could drive a truck up on it and the lugs won't fold over. The only flex is in the belt itself. Every year seems like the rubber compound gets a little harder. Don't surprise me though, same thing happens to my tractor tires. After 10 yrs now I can't even make a mark with my thumbnail on the lugs compared to new when they were soft and grippy.