It depends on your hub. If it's unsealed, then the ball bearings have different diameters - you just need to find out which size you need. That's fairly easy. If it's sealed, there is going to be a number on the side of the seal - usually a 4 digit number starting with a 6. That number identifies your bearing dimensions, that's the bearing size you need.
The standard BMX axle nut size for most BMX bikes is 3/8 inch.
The standard size of BMX axle nuts is typically 3/8 inch.
The standard thread size for BMX pedal installation is 9/16 inch.
The standard wheel size for Brompton bikes is 16 inches.
The standard wheel size of a Brompton bike is 16 inches.
20'' wheel size ,and roughly 25 pounds in weight ^_^
The standard bike wheel size for most bicycles is 26 inches.
The standard size of the axle nut for a bike wheel is typically 15mm.
The standard size of bicycle wheel bearings is typically 1/4 inch in diameter.
The standard BMX hub spacing measurement for most modern BMX bikes is 110mm.
The recommended rim tape size for a standard bicycle wheel is typically 18mm to 22mm in width.
To choose the right size and type of BMX bike tube for optimal performance and durability, you should consider the size of your bike's wheel, the width of the tire, and the type of riding you will be doing. Make sure to select a tube that matches the wheel size and tire width specifications of your BMX bike. Additionally, choose a tube made of high-quality materials that are puncture-resistant for better durability.