What is OS20?
Understand 451 versus 406, tire markings, and which measurements actually matter.
Wheel standards →OS20, explained.
We love the OS20 wheel size and want to make it easier for other riders to find clear, useful information about it.
Start here
The useful stuff, without the hunt.
OS20 information is scattered across product pages, old forum posts, and conversations at the track. These guides bring the basics together.
Will it fit?
Compare frame geometry, wheel clearance, forks, brakes, and your current setup.
Fit guide →What is available?
Find known OS20 frames, tires, rims, and tubes, with notes on real-world availability.
Parts & vendors →Why this site exists
OS20 is a great size, but learning what fits can be frustrating. Product names are inconsistent, tire choices are limited, and important details are often buried.
OS20BMX.com is a place to collect what we learn, keep the practical details current, and make the next rider’s search a little easier.