Standard 9/16" spindle fits for BMX, MTB, Mountain Bike, Hybrid bike, Old School, Cruiser, Cyclocross Bike, Dirt Jumper, Folding Bike, Road Bike- Touring, Track Bike, Unicycle, Urban Bike - Fixed Gear.
Standard 1/2" spindle fits for most 12 - 16” youth bicycles - Compatible with any bicycle with a 1/2” crank.