The correct fit for a flat 20inch bmx bike would be a rider that stands 155 cm.
Bmx bike sizes.
Racing bmx bikes are lightweight designed for speed and stability while freestyle bmx bikes are sturdier with thicker frames and tires designed for maneuverability while doing jumps and tricks.
Bmx bikes come in a bunch of different sizes ranging from 12 all the way to 26.
Including 20 25 20 5 20 75 and 21.
As a minimum you will need at least a 23 inside leg to be able to stand over a full size bmx bike.
When figuring out frame size only the rider s height is important.
The most popular sizes are in the 20 range.
Over the years this frame has been made in a variety of sizes ranging from 19 8 21 75inches with variations to the chainstays head tube angles and seat tube angles the 20inch bmx frame has been through a lot however one thing has remained the same the riders.