The chassis design used from 1926 to 1932 was similar to the 1922 -1924 Grand Prix Sunbeams following Ernest Henry concept for the 1922 Strasbourg Grand Prix Sunbeams. The wheelbase was 3”1/2 longer than the 1924/5 cars. Front axle built up in three parts; centre section tubular. The axle failed during the 1926 Formule Libre Spanish Grand Prix and was subsequently re-designed and strengthened for the Boulogne Speed Trial. Half elliptical springs all around; spring pads attaching the rear axle white-metaled lined journals to allow for the rotational movement of the axle casing. Axle and steering connections polished steel to enable crack detection.

The new 1932 chassis designed by Reid Railton for Thomson and Taylor and commissioned by new owner Sir Malcolm Campbell was lower and stiffer than the original 1926 Sunbeam chassis. Wider front axle located by two tubular radius arms pivoting on the chassis frame. New front springs on outriggers brackets slid in trunnions at their forward ends. Under-slung rear springs; chassis side members below rear axle. Two pairs of Hartford shock absorbers for each axle. Both front and rear track increased but the cars remained crab-tracked. New larger radiator. 

1926-1932: Wheelbase 8’10”. Track: front 4’3″, rear 3’11”. Dry weight 2,016lbs

From 1932: Track: front 4’10.5”, rear 4′ 2.5″.