SM 1500 Roadster

Once again, catering specifically to the export market, Singer introduced a twin carburettor version of the 4AD known as the SM 1500 Roadster.

The addition of a second carburetor produced a substantial boost in power and performance, increasing engine output from 48 h.p. for the 4AD to 58 h.p. for the SM 1500. This also provided an extra 5-6 m.p.h. in top gear and surprisingly had little impact on gas mileage.

The gear ratios remained unchanged, which prompted The Autocar to write ” the impression was gained that a higher top gear would be acceptable, not with the idea of increasing maximum speed, but of lowering the engine speed when cruising fast”.

Unfortunately, the specialty niche that SM 1500 had fallen into by this time seemed to isolate it more and more from the market. Buyers were replacing their open cars with closed Saloons and the Roadster was increasingly equated with the out and out sports cars. This meant that it had to compete for market share with the Triumph TR-2, the MG – TF and the Sunbeam Alpine. With an outmoded design and financial difficulties, the writing was on the wall. Only 189 of these cars were built in the final year of production prior to the takeover of Singer by Rootes in 1956.

Serial No. location — Right side of bulkhead under bonnet.
Engine No. location — Right side of cylinder block flywheel housing

Engine
Four cylinder, 73 mm. by 89.4 mm. = 1,497 c.c.
                       :in 2.874 X 3.52 cu in. = 91.36Overhead camshaftCompression ratio 7.47:1RAC rated 22 hpMax Torque 77 lb/ft at 2600 r.p.m.Maximum power 58 b.h.p. @ 4,600 r.p.m.Twin Solex 30 F.A.I. downdraft carburatorsIgnition B.12. Lucas coil service No. 45012

Gearbox and TransmissionFour speed gear box with ratios 4.44, 5.58, 8.62 and
        13.25 to 1. Reverse 13.25:1Synchromesh on second, third and fourth gearsHardy-Spicer open propeller shaftSpiral bevel final drive

Wheels and Brakes16 inch bolt on steel disc wheels5.00 X 16 inchGirling hydro-mechanical brakes with 9 in drums

SteeringBurman high efficiency

SuspensionFront independent coil springs and wishbone, rear semi-elliptic leafFront Armstrong telescopic shock absorbersRear Armstrong direct acting hydraulic shock absorbers

Main DimensionsWheelbase 7 ft. 7 ins.Track 3 ft 10 3/4 inOverall length 12 ft 9 inWidth 4 ft 10 inHeight 4 ft 10 1/2 inTurning circle 33 ftGround clearance 6 1/2 inWeight 15 1/2 cwt

Price
Initially for export only