Spray cold grate of outdoor grill with grilling spray. Prepare grill for medium indirect heat. 

Combine sugar, salt, garlic powder, paprika, and freshly ground black pepper in a small bowl; mix well. 

Spread 1 tablespoon mayonnaise on each drumstick. Sprinkle each drumstick evenly with seasoning mixture. 

Place drumsticks on grill grate over drip pan and cover grill with lid. 

Grill 1 ½ hours, or until drumsticks are tender when fork is inserted easily into meat and internal temperature registers 180°F. 

Source: National Turkey Federation