Coventry's Derby-Bentley rival — the world's first all-synchromesh production gearbox and independent front suspension.
The Speed 20 (1932–1936, 1,165 made per published production records) was built in Coventry across four variants, SA to SD. The SA carried a heavily modified Silver Eagle-derived 2,511 cc straight-six with triple SU carburettors, 87 bhp, in a new lowered "double-drop" chassis. The SB, launched at the 1933 London Motor Show, brought independent front suspension by transverse leaf spring and the world's first all-synchromesh gearbox in a production car — landmark fitments for the British industry. The SC (1935) enlarged the engine to 2,762 cc; the SD (1936) added a larger fuel tank and wider bodywork. Standard coachwork: Charlesworth four-door sports saloon or Cross & Ellis tourer, plus bespoke chassis.
The Speed 25 (launched August 1936, built to 1940, 391 made per published production records; approximately 220 known survivors) developed the line with a 3,571 cc seven-main-bearing straight-six, triple SUs, 106–110 bhp at 3,800 rpm, near-100 mph performance, a servo from 1937, and the same IFS and all-synchromesh gearbox; approximately 329 carried Charlesworth bodies and 39 Cross & Ellis tourer bodies. Chassis-only price £775 — around 40 per cent more than the average UK house. Period rival to the Derby Bentley 4¼-Litre and Lagonda LG45.
Alvis's finest pre-war era; long undervalued against equivalent Derby Bentleys, with open coachwork leading closed.
| Variant | Years | Production | Notes |
|---|---|---|---|
| Speed 20 SA | 1932–1933 | Within 1,165 total | 2,511 cc triple-SU straight-six, 87 bhp; double-drop chassis. |
| Speed 20 SB | 1933–1934 | Within 1,165 total | Independent front suspension and the world's first all-synchromesh production gearbox. |
| Speed 20 SC / SD | 1935–1936 | Within 1,165 total | 2,762 cc; SD with larger tank and wider bodywork; 130-inch wheelbase option. |
| Speed 25 | 1936–1940 | 391 | 3,571 cc seven-bearing straight-six, 106–110 bhp; ~329 Charlesworth bodies, 39 Cross & Ellis tourers; brake servo from 1937. |
Authenticate stamped chassis and engine numbers against factory or club records. For the Speed 20 and Speed 25 specifically, verify SA/SB/SC/SD variant against chassis records, confirm original coachwork (Charlesworth saloon or Cross & Ellis tourer) versus rebodies, and note the SB's landmark all-synchromesh gearbox and IFS.
Confirm body originality, panel identity and restoration standard against a marque specialist.
Confirm continuous service history and any rebuild history for the engine, transmission and driveline against a marque specialist.
Restoration standard, originality of body and driveline, and any documented ownership record are the main value drivers.
Regional ranges authored independently — each reflects its local market, not an FX conversion
Each region quoted in its local currency — independent market readings, not FX conversions
Open coachwork leads closed; the Speed 25 trades above the equivalent Speed 20; documented original-body cars command the premium.
Authored against aggregate public-market data and named price guides as set out in What to Pay; regional readings are independent, not FX conversions.
| Date | Auction | Car | Mileage | Result |
|---|
No recent public auction results currently meet our verification standard. We publish sale figures only from verified examples, and will update this guide as qualifying results become available.
Stable Hold — Alvis's finest pre-war era, long undervalued against equivalent Derby Bentleys.
Our view, not advice. This section is Car Collector International's editorial judgement on where this model sits in the collector market, based on the production, specification and market data set out in this guide. It is not a recommendation to buy or sell and it is not investment advice. Values can fall as well as rise.
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The valuation figures in this guide are for research purposes only and do not constitute financial or investment advice. See our full disclaimer.
