Husqvarna belt size chart by model and part number. The right belt for a Husqvarna machine is usually found by part number, not by guesswork and not by deck size alone. A proper belt size chart should help you match the belt type, width, and length before you order. Going by deck size alone is often not enough, especially when similar machines use different belt routes. Start with the model if you know it. But if the old belt number is still readable, use that first. Part numbers point to the exact belt because similar decks may use different routing and pulley layouts. Belt length must be close enough for the pulley path and tensioner range. Even a small difference can affect belt tracking and blade speed. Before ordering, confirm four things in order: machine model, belt function, belt width, and belt length. The deck belt drives the blades. The drive belt moves the machine. If a belt keeps jumping off, check the idlers, keepers, springs, and pulley alignment too.