The mount is the bolt pattern that fixes the frame to the boot — the frame and boot must share the same mount to fit together. Common standards are UFS (a flat mount used on most aggressive skates), 165mm and 195mm (the gap between the two bolts, found on most inline skates) and Trinity (Powerslide’s 3-point mount that sits lower for extra control). Always match your boot’s mount before changing frames.

Wheel hardness is the durometer — the “A” number. Higher (e.g. 100A) is harder: rolls faster but grips less and passes more buzz from the ground. Lower (e.g. 78A) is softer: more grip and a smoother ride, but it won’t roll as fast.

Frame length (in millimetres) sets your wheelbase. A longer frame is more stable and carries speed — better for fitness, distance and bigger wheels. A shorter frame is more nimble and easier to turn — better for slalom, freestyle, urban skating and smaller feet. It should also suit your boot size and wheel setup.