Simply drive slowly over the ramp, with the wheels in their straight-ahead position and the roller mounted top plate will move to show any toe-in or toe-out issues.
(BS) Gunson G4008 Trakrite Wheel Alignment Gauge Tool
Gunson G4008 Trakrite Wheel Alignment Gauge
GUNSON G4008 Trakrite Wheel Alignment Gauge Drive Over Roller Bearing Platform
Gunson Trakrite Wheel Alignment Gauge G4008
Gunson Trakrite Wheel Alignment Tracking Gauge Garage Paddock G4008