BMX BIKES, GET THE RIGHT FIT!
The first thing to make sure of is that you get a BMX Race bike, you will be at a disadvantage from the start if you buy a street/trick BMX, although you will still have a lot of fun on the track with one of those.
The next thing to consider is the size of your bike, it is very important, too small and you’ll be cramped leading to less bike control and too big will make it not only too heavy for you but also too hard for the rider to pull and pump around the track.
All BMX Race bikes except for two classes use 20″ wheels so the Top Tube length is used in sizing the bike.
Bikes with smaller top tube sizes will tend to have skinnier wheels to save weight and reduce rolling resistance. Handle bar widths and heights will also reduce along with crank length, so the top tube length on a bike will be sized in relation to other components on the bike.
The information below is intended as a guide only, you should visit the track or your local shop and ask to try different size bikes as every rider will have their own preferences. Crank length size in particular is very much rider preference once you get to the larger bikes.
Micro or Micro Mini:
15″ – 16″ top tube
18″ wheels
Crank Length 145mm – 155mm
Rider Height 4′ 4″ and under
Mini:
16″ – 17.5″ top tube
20″ Wheels
Crank Length 155mm – 165mm
Rider Height 4′ 2″ – 4′ 10″
Junior:
17″ – 18.5″ top tube
20″ Wheels
Crank Length 160mm – 175mm
Rider Height 4’6″ – 5′ 1″
Expert:
18.5″ – 19.5″ top tube
20″ Wheels
Crank Length 170mm – 175mm
Rider Height 5′ – 5′ 4″
Expert XL:
19.25″ – 20″ top tube
20″ Wheels
Crank Length 170mm – 175mm
Rider Height 5’2″ – 5’6″
Pro:
20″ – 20.5″ top tube
20″ Wheels
Crank Length 175mm – 180mm
Rider Height 5’3″ – 5’8″
Pro XL:
20.75″ – 21.25″ top tube
20″ Wheels
Crank Length 175mm – 185mm
Rider Height 5’7″ – 6′
Pro XXL:
21.25″ – 22″ top tube
20″ Wheels
Crank Length 180mm – 190mm
Rider Height 6′ +