I tried one time. I was at the annual Dealer Show in Indianapolis that is only open to the industry. I had been speaking with one of the Kenda reps about the Big Block and its use on the bigger adventure bikes likes the GS, Tenere, etc. As part of that conversation I mentioned that people had been putting a rear Big Block on the front of TW's and that they really needed to make one in a 180/80-14 for the rear. I indicated how there seemed to be a need for a more aggressive tire for that market, as there were people actually mounting ATV tires. He felt that the market share didn't warrant the effort required, and tires on smaller bikes last a lot longer so the frequency of purchase wouldn't be that high. Knobbies for big bikes are a better business decision since people with 100hp on tap wear out knobby tires quickly. A 10 or 12 hp TW often changes tires due to age, not wear.