By October 1950 the further improved 4AB Roadster appeared.
While superficially similar, this has an independent front suspension by coil springs and a hybrid, "hydro-mechanical" brake system by Girling.
Externally, there is a shortened bonnet and disc wheels, as well as fixed sides to the bonnet.
The fenders were also redesigned, becoming curvier and deeper.
The steering box also received alterations, mainly aimed at centering it in the chassis so as to simplify manufacturing alternately right-hand or left-hand driven examples.
The 4AB continued in production alongside the larger 4AD until January 1953.

The prototype 4AC (built in about a dozen examples) used a slightly larger 1194 cc engine.
This was a down-sleeved version of the 1.5 litre version as fitted to the Singer SM1500, and part of an attempt rationalize Singer's lineup.
By October 1950 the further improved 4AB Roadster appeared. While superficially similar, this has an independent front suspension by coil springs and a hybrid, "hydro-mechanical" brake system by Girling. Externally, there is a shortened bonnet and disc wheels, as well as fixed sides to the bonnet. The fenders were also redesigned, becoming curvier and deeper. The steering box also received alterations, mainly aimed at centering it in the chassis so as to simplify manufacturing alternately right-hand or left-hand driven examples. The 4AB continued in production alongside the larger 4AD until January 1953.
The prototype 4AC (built in about a dozen examples) used a slightly larger 1194 cc engine. This was a down-sleeved version of the 1.5 litre version as fitted to the Singer SM1500, and part of an attempt rationalize Singer's lineup.
Singer Roadster