What size BMX Bike?

August 30, 2025
Bmx Bikes

How will you know very well what bike size you ought to ride? Here is a chart to help show you.

BMX Bicycle Sizing

Rider Level	Frame Size	Top Tube Length	Stem Length	Club Increase	Bar Width	Crank Length	Gearing
4’0″ & under	Micro-Mini	15″- 15.5″	Mini	2″-2.5″	20″- 21.5″	See Chart Below	See Calculator Below
4’0″-4’6″	15.5″- 16.5″	Mini Mini XL	2″-3.5″	21″- 23″
4’4″-4’10”	Junior	16″- 17.5″	3″-4.5″	22″- 24.5″
4’8″-5’4″	Specialist	17″- 18.5″	Pro	4.5″-6″	24″- 26″
5’2″-5’8″	Specialist XL	18″-19″	6″-7.5″	26″- 27″
5’6″ – 5’10”	18.5″- 19.5″	Pro Professional XL	7″-8″	27″- 28″
5’10”-6’1″	Professional XL	19″-21″	17″- 28″
6′ & over	Pro XXL	20.5″ & over	Professional XL Pro XXL	28″- ?”

Wheel Models

Max Rider Body Weight	Rim Width
0 – 85 pounds	Sew Ups
86 – 100	20 x 1-1/8″
101 – 120	20 x 1-3/8″
121 – 150	20 x 1.50″
151 – 200	20 x 1.75″

Crank Sizing

Riders Inseam	20″	21″	22″	23″	24″	25″	26″
140mm	145mm	150mm	155mm	160mm	162mm	166mm
27″	28″	29″	30″	31″	32″	34″
171mm	175mm	177mm	180mm	182mm	185mm	190mm

Gearing

Exactly What Equipment If You Run? Most cyclists regardless of class seem to like a roll-out of approximately 53″ – 54″. To work your roll-out here is the formula:

** Sprocket divided by Freewheel times Tire Diameter **