I replaced the flat/cracked rubber tires on my old Sears car - green, 2 tires (circa 2001) with this kit and the quality* is much better than the originals. higher tire height from the axle, raising the handlebars another inch off the ground. The Rockies have bearings in the wheel shaft. Where my old decrepit tire design had all metal bushings in the ends of the shaft housing - rode right on the axle! If I had known this earlier, I would have made the changes much sooner. Now, for comparison, it's like gliding in a fast forward wind. now turn on each side. No more stress in the field! Bought 6/16/2019 and to this day - still holds air and runs on demand when you push.