Stand over the bike with feet flat on the ground and measure the clearance between your body and the top tube
Measure your inseam from the crotch to the floor while barefoot
Multiply your inseam by the bike type sizing factor to estimate frame size
Check the manufacturer’s size chart for the specific bike model
Measure your torso length from crotch to base of neck
Measure your arm length from shoulder to wrist
Compare torso and arm measurements with the bike’s geometry chart
Measure the seat tube length from the center of the bottom bracket to the top of the seat tube
Measure the top tube length to assess reach
Test saddle height and handlebar reach for proper fit
Verify that you can comfortably reach the handlebars and brakes
Confirm that your knees do not hit the handlebars when pedaling
Check that you can stand over the frame with adequate clearance
Consider wheel size and bike type when selecting frame size
Use a professional bike fit if you need precise sizing