After 1981 all Sportsters had a 1' steering stem, including all 39mm Narrow Glide forks.
1977 & earlier Sportsters had a 7/8' stem, which was changed to 15/16' for 1978-1981. Harley-Davidsons typically have a 1' outside diameter steering stem. Steering stem: The steering stem connects the center of the upper and lower triple tree, which in turn holds the forks.Axle: The front axle is located perpendicular and engages the sliders.The sliders house the dampening assemblies, which vary based on the brand and type of fork.
Sliders : At the bottom of the fork tubes are the lower legs, often referred to as sliders.Triple trees: The triple trees (also known as yokes) hold the fork tubes (which contain the fork springs), and are fastened to the neck of the frame by the steering stem.Here's a basic diagram of components that make up a motorcycle front end.
