Alvis Speed 20SB Tourer by Vanden Plas
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Car producer : |
Alvis |
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Model: |
Speed 20SB Tourer by Vanden Plas |
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Year: |
1933-1935 |
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Type: |
Tourer |
The Alvis 12/50 is a car introduced by British business Alvis Car and Engineering Company Ltd in 1923. It went through a series of versions, with the last ones being made in 1932. A range of factory bodies (made by Carbodies and Cross & Ellis) could be specified in two- or four-seat form, with either open or closed bodies.
The first models were designated SA and SB and had a 1496 cc 4-cylinder overhead valve engine in a chassis with a wheelbase of 108.5 in (2,756 mm) for the SA and 112.5 in (2,858 mm) for the SB. The engines of these early cars were carried in a subframe bolted to the relatively slender ladder chassis. The SA usually carried two-seat bodywork; often the classic so-called "duck's back" style named after its pointed rear end, which was said to resemble that of a duck. The SA and SB 12/50s were built with brakes on the rear wheels only. All the 12/50s had a four speed non-synchromesh gearbox with right hand change. The cars were right hand drive.
The SC arrived in Autumn 1924 for the 1925 model year with a larger 1598 cc engine (unless the 1496 cc unit was specified for sporting use) and, like all the remaining cars, the longer chassis. Front wheel brakes were offered as an option on this model.
A new stronger chassis was designed and used for the TE of 1926, which had its engine (now built around a redesigned crankcase) enlarged again to 1645 cc, and the TF of the same year which retained the smaller 1496 cc version. A single-plate clutch replaced the previous cone type, and for these and all subsequent 12/50s the engine was bolted directly to the chassis, dispensing with the subframe of previous models. From the TE and TF models onwards four-wheel brakes were fitted as standard.
The TE and TF were superseded in 1927 by the TG and SD with large and small engine respectively. The TG was the standard 'touring' model, while the SD - powered by the 1496cc engine, now fitted with a large-port cylinder head - satisfied the needs of the sporting motorist. Also available in this year was the TH, which had the gearbox and rear axle ratios of the 'touring' TG, but the sub-1500cc engine of the SD. The TG and SD models were available until 1929.
The 12/50 was withdrawn between 1929 and 1930 when the company decided that the future lay with the front-wheel drive FD and FE models, but when these did not reach the hoped for volumes a final version of the 12/50 was announced as the 1645 cc 1931 TJ continuing until 1932. The TJ is referred to by Alvis historians as being from the 'revival period', and it differs from its predecessor in a number of ways, notably coil instead of magneto ignition, deep chromed radiator shell, and rear petrol tank in place of the scuttle-mounted tank on most older 12/50s.
In 1931 the 12/50 was joined by an even sportier partner, the 12/60hp. Introduced in 1931, the 12/60 came with a raised compression ratio and twin carburetors, modifications that raised its maximum power to 56bhp. A sports saloon, four-seater sports and two-seater sports were offered, the last clothed in graceful 'beetleback' coachwork. Testing a 12/60 'beetleback' in 1931, Motor Sport found that the car could almost touch 80mph, yet was capable of returning 30mpg even when driven hard. Today, Alvis's 12/50 and 12/60 are among the most highly sought after sports cars of their day, with an enthusiastic following worldwide.
The engine for the Speed 20 was a heavily modified version of the one used in the preceding Silver Eagle cars, producing 87 bhp (65 kW). Triple SU carburettors were fitted. The chassis was new and lowered by making it a "double drop" type where the side rails go over the front and rear axles. A centralised lubrication system was fitted allowing oil to be provided to moving suspension parts through a maze of pipework. Both front and rear suspension used half-elliptic leaf springs and the brakes with 14 in (356 mm) drums, mechanically operated. The four-speed manual gearbox was mounted in-unit with the engine.
The car could be fitted with a variety of coachwork. Standard bodies were a four-door saloon from coachbuilders Charlesworth or four-door tourer by Cross and Ellis, but some cars were supplied in chassis form and carried bodies by coachbuilders such as Vanden Plas.
Approximately 400 of the SA cars were made.
The SB launched at the 1933 London Motor Show had a new chassis, slightly longer at 124 in (3,150 mm), with independent front suspension using a transverse leaf spring. The engine remained the same but the gearbox gained synchromesh on bottom gear and was mounted separately from the engine. A built-in jacking system was fitted as standard.
As with the SA, a wide range of bodies were fitted to the cars. Large Lucas 12 in (305 mm) P100 headlamps became standard, adding to the sporting appearance of the car.
