BMX bikes are used for tricks that require skillful riding and a bike that fits perfectly. Therefore, knowing how to measure a BMX frame correctly is crucial to ensure safety and comfort when riding, jumping, and doing flips.
BMX bikes come in two main frame types—freestyle and racing—used for different riding types, but measured similarly.
On this page, you’ll find an easy-to-use online calculator that teaches you how to measure a BMX bike frame and determine whether or not it fits you.
How to Measure a BMX Bike Frame?
Unlike other types of bikes that are measured by the length of the seat tube, a BMX bike is measured by the length of the top tube.
The top tube is the horizontal tube that connects the seat tube with the head tube, measured from the center of the seat tube to the center of the top tube and expressed in inches.
Below, you can choose your style of BMX bike, choose the length of the top tube from the drop-down menu, and get a detailed size chart with a height range for that frame size.
What style of BMX bike do you have?
Freestyle BMX Bike
Freestyle BMX bikes are heavier and stronger with 20" tires.
Racing BMX Bike
Racing BMX bikes have strong, light frames with 20" or 24" tires.
Frequently Asked Questions
1. How do you measure frame size for BMX?
BMX frame sizes are measured based on the length of the top tube. The top tube is the horizontal tube that connects the seat tube and the head tube, measured from the center of the seat tube to the center of the head tube and expressed in inches.
2. Does BMX frame size matter?
BMX frame size matters a lot, perhaps even more than for other types of bikes, as BMX bicycles are typically used for performing risky tricks and jumps. Therefore, it is crucial to know how to measure a BMX bike correctly and choose a frame size that fits your height.
3. What age is a 24-inch BMX bike for?
Kids' 24-inch BMX bikes are suitable for older school kids and younger teens, aged from around 10-14 years, depending on their height and leg length. However, racing BMX bikes for adults with 24" wheels fit adult riders, but the exact height range depends on the length of the top tube.
4. Can a 7-year-old ride a 20-inch BMX?
Yes, a 7-year-old can ride a Freestyle kids' BMX bike with 20-inch wheels, which would be the ideal size for most 7-year-olds based on their average height. However, a 7-year-old might struggle to ride a racing BMX bike with 20-inch wheels and an adult frame size with a long top tube.