UPDATED JANUARY 2025
The Quik Rack Mach2 bike rack can be used with almost all bikes that weigh 120 pounds or less. More specifically, it handles a wheelbase of 56″ with wheel sizes from 12″ to 29″, and anywhere from skinny road bike tires up to a 5″ wide tire with no adapters needed.
The rack is not designed to carry trikes.
See the no-tools tire size adjustment in action:
Here is an image of the bike size range dimensions.