The invention relates to a method and apparatus for dynamically measuring vehicle front end parameters such as tow-in (or toe-out) and camber angle. The apparatus includes a separate pair of support rollers (11) for supporting each vehicle front wheel (10) and causing rotation thereof. A sensing roller (12) is adapted to contact the tyre tread surface at the lowermost point of the tyre so as to be rotated by rotation of the wheel. The axis of the sensing roller (12) is arranged transverse to the plane or rotation of the wheel (10) such that any toe-in or toe-out of the wheel causes a transverse or generally axial displacement of the sensing roller (12) to a - position wherein the axis of the sensing roller is normal to the toe-in or toe-out direction of the wheel (10). The sensing roller (12) is mounted on an axle (13) which forms one bar of a trapezium shaped four bar linkage (13,14,15) which causes said sensing roller (12) to pivot about an effective pivot point ( 1 6) which is arranged, by means of said linkage, a considerable distance away from the wheel (10). The pivot point (16) is the point of intersection of the centre lines of the tapered sides (14) of the linkage since the bars of the linkage are pivotally interconnected. A further sensing roller for measuring camber angle and methods of measuring toe-in and camber angle are also disclosed and claimed.