The rails are not adjustable on the trike carrier, below are the dimensions for the rails. The wheel stop is movable.Dimensions of Carrier:
- Carrier rail length: 71.5"
- Center carrier rail width: 6.375"
- Outer carrier rails width: 9.25"
- Center ramp length:57.5"
- Outer ramp length:60"
- Center ramp width:5.5"
- Outer ramp width:10"
- Main tube length: 50"