• Standard Hydraulic: Uses internal dampening, oil, and springs; common sizes are 39mm, 41mm, and 49mm depending on the model year.
• Springer: A rigid, traditional mechanical setup using external springs and rocker links instead of internal oil dampening.
• Inverted (Upside-Down): Puts the thicker upper tubes at the triple tree for maximum rigidity and high-performance handling.

• Sportsters (1987–2015): Typically use 39mm tubes.
• Big Twins (1949–2005): Generally use 41mm tubes.
• Modern Big Twins & late Sportster Forty-Eights: Upgraded to heavy-duty 49mm tubes.
• Tip: Always measure with a caliper or check your specific model's service manual before buying clamp-on accessories like headlight brackets or fork-mounted driving lights.

• Fitment Limits: Traditional aftermarket Springer front ends are designed for specific classic frames (like vintage Sportsters and Big Twins with 1-inch neck stems).
• Incompatibilities: Most standard custom Springers do not fit rubber-mounted Sportsters (2004-present), Dynas, or modern FLT Touring models without specialized custom neck conversions.

• Narrow Glide: Center-to-center distance of 7.00 inches.
• Mid Glide: Center-to-center distance of 8.437 inches.
• Wide Glide: Center-to-center distance of 9.875 inches.
• Note: The width of your triple trees dictates your choice of front wheel, fender clearance, and overall steering leverage.

• Cosmetic Kits (Slider Covers/Lowers): Can be installed at home with basic garage tools if you follow torque specs and replace fork seals correctly.
• Full Conversions (Raked, Springer, or Inverted Swaps): Require precise steering head bearing adjustment (fall-away test) and alignment. If you alter the rake and trail significantly, professional tuning is recommended to avoid high-speed stability issues.