Gates did extensive field testing with several snowmobile clubs in Canada and also did extensive "focused" testing on "hypersleds" under very difficult conditions including drag racing and deep powder riding. We never detected abnormal pulley wear on any of the sleds. In addition, we did extensive accelerated laboratory testing on using actual snowmobile clutches. If there was a problem with our belt causing excessive wear, we would have quickly detected the problem.
Now let's talk about belt hardness and wear. Wear resistance does not have to be accomplished with "hard" material. The Xtreme belt is actually "softer' than other high performance belts on the market. You can check this for yourself with the old "thumbnail" test. Simply use your thumbnail or a pointed object and "measure" the effort it takes to penetrate the belt undercord material about 1/32 of an inch. Xtreme derives it's wear resistance from some very proprietary compounding of the rubber material. None of the components of the undercord material will cause any increase in pulley wear.
Accelerated pulley wear can be caused by dirty belts, especially if they have been subjected to dirt or sand during marginal riding conditions or during grass or asphalt drag racing, by excessive slippage resulting from improperly calibrated clutches, or by a excessive drive misalignment. These conditions will cause wear regardless of the belt construction.