ProTaper – ProTaper Tire Tubes, including heavy duty front tubes in 80/100-21, and rear tubes in 100/90-19, 110/90-19, 120/80-19, 110/100-18 and 120/100-18, handles the unglamorous component that ends more rides than any other failure. A heavy duty tube uses thicker butyl walls than a standard replacement, which resists pinch flats when a rim hits a square-edged rock, a root or a hard-packed rut at speed. That extra material also holds up better to the heat and flex generated by low pressures, so riders running soft settings for traction in sand or on rocks are less likely to pay for it with a flat. Sizes here cover the standard motocross and off-road setup: an 80/100-21 front paired with 19-inch rears in 100/90, 110/90 and 120/80 for motocross machines, and 18-inch options in 110/100 and 120/100 for enduro and cross-country bikes. Correct sizing matters, because a tube that is too small stretches thin and one that is too large folds and chafes against itself. Running a properly sized ProTaper heavy duty tube means fewer interruptions, more confidence pushing into rough terrain, and consistent tire pressure through a full day of riding.