Riders: U
- Monster Energy AMA Supercross Championship
- AMA Pro Motocross Championship
- SuperMotocross World Championship
- FIM Motocross World Championship
- Progressive GNCC Racing
- Motocross of Nations
- FIM World Supercross Championship
- Australian Supercross Championship
- Women's Motocross Championship
- Monster Energy Cup
-
Simeo Ubach
Spain -
Ömer Uçum
Turkey -
Colton Udall
San Clemente, CA -
Kevin Uebrick
Middle Grove, NY -
Zach Ufimzeff
Canada -
Cole Ughetti
Battle Creek, MI -
H Scott Uhrmann
Linwood, NJ -
Olga Ukrainets
-
Kylar Ulibarri
-
Manuel Ulivi
Italy -
Don Ullery
Cooper City, FL -
Austin Ullrich
Estacada, OR -
Dennis Ullrich
Germany -
Dan Ulven
Silverton, OR -
Vanessa Umschaden
Austria -
Ryan Underhill
Crown Point, IN -
Jet Underwood
Lakewood, CO -
Jonathan Underwood
Lakewood, CO -
Scott Underwood
Las Vegas, NV -
John Untiedt
Alexandria, VA -
Jason Upshaw
Gainesville, TX -
Donald Upton
Sun City, CA -
Bill Urban
San Diego, CA -
Glen Urquhart
Humble, TX -
Kevin Urquhart
Kent, WA -
Francisco Urrutia
Uruguay -
Rhett Urseth
Casa Grande, AZ -
Bill Ursic
Scenery Hill, PA -
TJ Uselman
Willow Park, TX -
Tony Usko
Doylestown, OH