TriumphTR4

Triumph TR4A

The TR4A of 1965–67: the TR4's body on a new frame with independent rear suspension, badged TR4A IRS and often called the TR4 IRS, a name Triumph never used, and, for North America only, a cheaper TR4A with the old live axle. American usage wrote TR-4A; some books write TR4-A.

A red Triumph TR4A with its black hood up and a luggage rack, seen from behind on a brick lane beside a white cottage.
A red TR4A with its hood up and a luggage rack, seen from behind at De Waal, Texel, the Netherlands, in June 2017.Joachim Kohler, CC BY-SA 4.0

Although we were unable to accept Standard-Triumph's invitation to drive to Geneva in the new 104-b.h.p. Triumph TR4A with all-round independent suspension we acknowledge that here is another maker convinced that i.r.s. is a worthwhile improvement.

Motor Sport, April 1965

The TR4A kept the TR4's body, with a new grille, new lamps and new badges, and put it on a new frame with independent rear suspension by semi-trailing arms and coil springs, related to the Triumph 2000 saloon's (sedan's). Its boot (trunk) carries a TR4A badge, and an IRS badge on cars with the independent suspension, which is why the car is often called the TR4 IRS. Triumph built it from January 1965 to July 1967, and showed it at Geneva in March 1965. For the United States and Canada only, it also built a cheaper TR4A with the TR4's live axle on leaf springs, which the North American distributors had asked for. Its total is in the production readings.⁠1​2​3​4

Why the TR4A

A dark green Triumph TR4A with its hood down, seen from the front left in a circuit paddock among other classic cars.
A dark green TR4A in the paddock at the Nationaal Oldtimer Festival, Zandvoort, in September 2009.Alf van Beem, CC0

The criticism the TR4 met most often was its ride, harsh on rough roads. Independent rear suspension had been considered for the TR4 and dropped on cost, Ate Up With Motor writes. By 1962 the TR4 was about to become the company's only car with a live axle: the Herald, the Vitesse and the coming Spitfire already had independent rear suspension, the semi-trailing arms of the 2000 saloon were in development, and the company was returning to profit. Harry Webster's independent suspension for the TR goes back to around 1962, by the Vintage Triumph Register's account after Graham Robson, and the German TR Register adds that dealers and customers were asking for a softer ride.

The change went deeper than its single letter suggests. Robson, as the Register quotes him, judged that "the TR4A was as different, in its own way, from the TR4, as that car had been from the TR3A".⁠3​5​6​4

Contents

The new frame and suspension

The frame was new: Robson calls it "an entirely new type of chassis frame", and Ate Up With Motor describes it as almost completely redesigned, on the same wheelbase, with the side rails reshaped and stiffened. Krause adds that the rails moved outward between the wheels, and the German TR Register that the frame was stronger from the middle back, with crossmembers and reinforcing plates welded in layers.

At the back, big cast-aluminium semi-trailing arms carried the wheels on coil springs, with lever-arm dampers mounted across the car, since there was no room for telescopic ones, and a pressed-steel bridge, rubber-mounted to the frame, carried the differential. Splined half-shafts took up the changes in track, and could bind under power: "the splines had a tendency to jam", Krause writes. Revington TR's description of the rear end counts "6 universal joints, 3 prop shafts and 2 trailing arms". At the front the double wishbones and coil springs stayed, with more travel, new geometry and adjustable camber, and the steering was made slower, by about a fifth, Ate Up With Motor reckons.

When the prototypes were ready, Stanley Markland is said to have pronounced the new chassis "safe for 120 mph", a story the Vintage Triumph Register retells from Robson.

Close-up of a red Triumph's boot corner, showing the chrome 'TR4A' and 'IRS' badges above the bumper and overrider.
A TR4A's boot lid in Dorset, May 2016: the TR4A script, with the IRS badge beneath it.Andrew Bone, CC BY 2.0

Contents

Engine and running gear

The engine was the TR4's wet-liner four, with a new intake manifold and a twin-pipe exhaust, which together, Ate Up With Motor writes, added about 4% to its power; the exhaust also took away most of the old car's bark. The specifications below give its ratings, net and gross; at what engine speed its power peaked the German TR Register and the TR Drivers' Club disagree. The importer's owners' newsletter listed the American car's changes in March 1965: a one-piece air cleaner with paper elements, a four-branch exhaust manifold and new silencers, a new camshaft and valve springs, a no-loss cooling system, positive crankcase ventilation, a diaphragm clutch, and revised front suspension geometry with a higher roll centre.

The first TR4As had Zenith-Stromberg carburettors, as the later TR4s did, and SUs came back during the run: from CTC62191 by Piggott's lists as the Vintage Triumph Register gives them, or from CTC61291 by Revington TR's, the same digits in another order. Both types were fitted to later cars, and Ate Up With Motor suggests the return to SUs may have been for reasons of supply. Live-axle cars, from about CT70000, had a single transverse silencer box in place of the twin silencers. Whether the 2-litre engine was offered on the TR4A the sources disagree, and TR4 vs TR4A gives both views.⁠3​9​6​10​4​11

The engine bay of a green Triumph TR, showing the chrome rocker cover, twin SU carburettors with round air filters and the distributor.
The four-cylinder engine with twin SU carburettors, in a car described as a TR4A, at Mülheim-Kärlich, Germany, in May 2009; nothing in the picture tells a TR4A from a TR4.Lothar Spurzem, CC BY-SA 2.0 de

Contents

Body, trim and identification

Outside, the TR4A had an extruded aluminium grille of horizontal bars in place of the TR4's stamped one, and its sidelamps and indicators moved from the grille to pods on the front wings (fenders), joined by a chrome strip that runs back through the doors. The bonnet (hood) badge became the Triumph globe, with smooth TRIUMPH letters; the overriders (bumper guards) moved outward and the front bumper rose a little; the boot carried a TR4A badge, and IRS on cars that had it. The bulge on the bonnet kept the later TR4's long shape.

The hood (soft top) followed the Herald's pattern, quicker to raise, folding into the space behind the seats under a cover, which largely ruled out the cushion that TR4 owners could fit there; Revington TR praises its "proper catches at the front". Inside, a walnut dashboard was standard, the handbrake moved onto the transmission tunnel between new seats, the gear lever was shorter, the tops of the doors were trimmed and the wipers had two speeds. The importer's newsletter of March 1965 promised American buyers leather seats, carpet and a centre console.

The roof options stayed. A "Hard-top model" appears in the British prices of the maker's advertisement of May 1966, and the TR Register names hardtops as options on both cars. The Vintage Triumph Register rates the Surrey top highly and writes that, as far as its author knows, the factory never offered a hardtop; it uses the name Surrey top for the two-piece roof, and so means only that there was no one-piece factory hardtop. Wheels were pressed steel, with 60-spoke wire wheels an option and Silverstone alloys for competition; the cars came on cross-ply tyres as standard, but most American cars, the Vintage Triumph Register says, left on radials, usually Michelin X.⁠3​11​6​5​9​12​13​7

The front of a red Triumph TR4A seen almost head-on, showing its horizontal-bar grille, twin headlamps and wing-top lamps.
A TR4A's front, almost head-on, in June 2008: the grille of horizontal bars and the lamp pods on the wing tops.Lothar Spurzem, CC BY-SA 2.0 de
The cockpit of a red Triumph with a walnut dashboard and wood-rim steering wheel, seen from behind over the folded hood.
A walnut dashboard in a car described as a TR4A, in Dorset in May 2016; the wood-rim wheel is not original.Andrew Bone, CC BY 2.0

Contents

Running changes

The TR4A's change points come from Piggott's lists as the Vintage Triumph Register gives them, and from Revington TR where it differs.

ChangeFromSource
The first TR4ACTC50001, January 1965; CTC50006, built on 5 January 1965, is the first production car on Rimmer's listVintage Triumph Register; Rimmer
The first live-axle TR4ACT50001Revington TR
Gearbox (transmission) and clutch housing modifiedCTC50125Vintage Triumph Register
Longer front springs in place of short ones with spacersCTC59836Vintage Triumph Register
SU carburettors in place of StrombergsCTC62191, or CTC61291 by Revington TRVintage Triumph Register; Revington TR
Temperature sender and gauge modifiedCTC62637Vintage Triumph Register
Cross-box exhaust on live-axle carsAbout CT70000Revington TR
The last TR4ACTC78684, built on 11 July 1967; CTC78687, the highest number, was built on 10 JulyRimmer

As with the TR4, Rimmer's list runs by year of build, and its model-year label for the cars built in 1967 is 1966. These ranges count numbers rather than cars, and the live-axle CT cars share the series with the CTC cars, so both forms are counted together:

Year of buildCommission numbers
1965CTC50006 to CTC64147
1966CTC64148 to CTC75171
1967CTC75172 to CTC78687

For 1966 and 1967 the approximate yearly figures that the Vintage Triumph Register takes from Piggott come to more cars than Rimmer's list has numbers.⁠6​10​2

A dark blue Triumph TR4A with a beige hood up, seen from behind on the grass paddock of a hill-climb.
The twin exhaust pipes and TR4A badge of a dark blue TR4A at Shelsley Walsh, Worcestershire, in July 2017.Daniel Milner, CC BY-SA 4.0

Contents

Driving: what the testers found

The testers of 1965 and 1966 agreed that the ride was much better, and found new faults with it, as Ate Up With Motor's digest of Motor, Autocar, Car and Driver and Motor Trend sets out: rear springs soft enough to bottom and to squat under power, half-shaft splines that bound, more body lean, slower steering, rubber bushes that let the suspension deflect, and a new tendency for the tail to swing out when the driver lifted off in a bend.

The greatest improvement in the TR undoubtedly comes from the rear suspension. Now the TR can be driven deliberately fast at obstacles it would have shied away from before.

Autocar, 1965, as quoted by G. William Krause

It was not faster. Krause writes that the TR4A gave up a second in the standing quarter-mile, and nearly as much from rest to 97 km/h (60 mph), against the TR4, and the Vintage Triumph Register, following Robson, that it was "not as fast on the road as the critics expected". Motor Sport's editor was in no doubt about the TR4A: answering a reader's complaint about noise in 1967, he asked whether the reader had been using a TR4, since "The 'A' is a big improvement in many ways". More of what the period testers wrote is on the road tests page.⁠3​5​6​14

A red Triumph TR4A with its hood folded arrives along a parkland drive, seen from the front three-quarter.
Arriving at the Lulworth Castle motor show, Dorset, in September 2022: a TR4A by its photographer's account.Andrew Bone, CC BY 2.0

Contents

The live-axle TR4A

The live-axle TR4A was a car for the United States and Canada alone. It kept the TR4A's body and its new frame, but had no bridge or trailing arms: long leaf springs on brackets carried a live axle, as on the TR4, with lever-arm dampers. Its commission numbers carry the TR4's CT prefix in the TR4A's series, from CT50001, and it has no IRS badge. The Rimmer catalogue's introduction records it as sold only in North America.

The reason was price. Independent suspension cost more, and Genser-Forman, Triumph's distributor in the north-east, feared that it would carry the American list price over $3,000; Robson calls the result an "entry-level" TR4A, and Standard-Triumph made independent suspension an extra-cost option on the American car. The importer's owners' newsletter told its readers in March 1965 that the difference the option made "must be experienced to be appreciated", and that at the price "it's a steal".

How many live-axle cars were built is not known. No factory figure has been published, and the only estimate from a reliable source is Graham Robson's, in his essay for Rimmer's parts catalogue:

… about 10,000 of total TR4A production (of 28,465) had this layout …

Graham Robson, in Rimmer's TR2–TR250 parts catalogue

The German TR Register and Ate Up With Motor both say the exact number is not known, and a figure of about a quarter also circulates, without a source.

A green live-axle TR4A, with no IRS badge, driven on Massachusetts roads; the car is modified, with Weber carburettors, alloy wheels and wider tyres.Video: 1966 Triumph TR4A - The Classic British Roadster You Can AFFORD To OWN (POV Binaural Audio), Tedward, 2024

Revington TR's verdict on the experiment is blunt: the American dealers, it writes, "eventually saw sense", taking the cars with independent suspension and "condemning the adapted live axle cars to the history books".⁠2​3​6​11​13​4​9​7

Contents

Specification: TR4A IRS

Production

Sources for Production, TR4A IRS

Built
One good source.TR4A commission numbers, first and last. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Designers
One good source.TR4A, basic summary. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Built at
One good source.The production table's heading. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
BuiltCTC50006 (5 Jan 1965) to CTC78684 (11 Jul 1967)
DesignersGiovanni Michelotti (body)
Built atCanley

Engine

Sources for Engine, TR4A IRS

Capacity
One good source.TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13
Engine position
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Block
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinder head
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Valve gear
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Bore × stroke
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Compression ratio
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel system
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cooling
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinder layout
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinders
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Ignition
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cycle
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Lubrication
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Capacity2138 cc
Engine positionFront
BlockCast iron
Cylinder headCast iron
Valve gearOHV, 2 valves per cylinder
Bore × stroke86 x 92 mm
Compression ratio9.0:1
Fuel systemCarburetor
CoolingWater-cooled
Cylinder layoutInline
Cylinders4
FuelPetrol
IgnitionCoil and distributor
CycleFour-stroke
LubricationWet Sump

Performance

Sources for Performance, TR4A IRS

Power
Good sources disagree.Motor Sport, "Matters of moment, April 1965", Apr 1965, p. 11⁠1; Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13; Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4; TR Drivers Club, "Early Cars: The TR4A"⁠11
Torque
Good sources agree.Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; TR Drivers Club, "Early Cars: The TR4A"⁠11; Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Top speed
One good source.Maker's claim; "cruises comfortably at 90 mph". Motor Sport, "Cornering fast in a Triumph TR4A…" (Standard-Triumph advertisement, with price list), May 1966, p. 49⁠12
Power104 bhp

Power, TR4A IRS

Good sources disagree.

  • 104 bhpGood sources agree: Motor Sport, "Matters of moment, April 1965", Apr 1965, p. 11, "the new 104-b.h.p. Triumph TR4A with all-round independent suspension"; rating not stated⁠1; Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012, net ("109 gross horsepower … 104 hp … net")⁠3; TR Register, "Triumph TR4 / TR4A Buyers Guide", "All cars had 104bhp/2138cc"; rating not stated⁠13; TR Drivers Club, "Early Cars: The TR4A", at 4,600 rpm⁠11
  • 104 PSDisputed: Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF), at 4,700 rpm⁠4
  • 109 bhpOne good source: Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012, gross⁠3
Torque132 lb ft
Top speed110 mph

Running gear

Sources for Running gear, TR4A IRS

Steering
One good source.TR4 and TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Gearbox
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Gears
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Overdrive
One good source.Optional; TR4 and TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Layout
One good source.TR4A IRS. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
Front brakes
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Rear brakes
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Front suspension
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Rear suspension
Several figures in print.Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017⁠5
Tyres
Several figures in print.Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6; Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Wheels
One good source.TR4A. Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6
Final drive
One good source.TR4A IRS. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
Clutch
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Steeringrack and pinion
GearboxManual
Gears4
OverdriveA-type, on 2nd to 4th
LayoutRWD
Front brakesDisc, 11 in
Rear brakesDrum, 9 in
Front suspensionIndependent, double wishbones, coil springs, telescopic dampers
Rear suspensionsemi-trailing "big aluminum" arms, coil springs, lever-arm dampers

Rear suspension, TR4A IRS

Several figures in print.

  • semi-trailing "big aluminum" arms, coil springs, lever-arm dampersGood sources agree: Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
  • semi-trailing arms, coil springs, lever-arm dampers mounted transverselyGood sources agree: G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017⁠5
Tyrescross-plies (5.50/5.90-15) as standard; most cars on radials, usually Michelin X 165-15

Tyres, TR4A IRS

Several figures in print.

  • cross-plies (5.50/5.90-15) as standard; most cars on radials, usually Michelin X 165-15One good source: Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering), TR4A⁠6
  • 6.95 x 15 cross-ply; 165 x 15 radialOne good source: Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1, tyre-pressure table, TR4 and TR4A⁠2
Wheels4½J x 15 pressed steel; 60-spoke wire wheels optional
Final driveShaft
ClutchDry single plate

Body and chassis

Sources for Body and chassis, TR4A IRS

Body
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Body material
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Seats
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Chassis material
One good source.The TR4A frame. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
BodyRoadster
Body materialSteel
Seats2
Chassis materialSteel

Dimensions and weight

Sources for Dimensions and weight, TR4A IRS

Length
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Width
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Height
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Kerb weight
Several figures in print.G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017⁠5; Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Wheelbase
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel tank
One good source.TR4 and TR4A. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Length391.0 cm
Width147.0 cm
Height127.0 cm
Kerb weightnearly 2,240 lb

Kerb weight, TR4A IRS

Several figures in print.

  • nearly 2,240 lbOne good source: G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017, IRS car⁠5
  • 1005 kgNot yet confirmed: Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF), TR4A, kerb⁠4
Wheelbase223.5 cm
Fuel tank11.75 gal

Contents

Specification: TR4A (solid axle)

Production

Sources for Production, TR4A (solid axle)

Built
One good source.TR4A commission numbers, first and last. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Designers
One good source.TR4A, basic summary. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Built at
One good source.The production table's heading. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
BuiltCTC50006 (5 Jan 1965) to CTC78684 (11 Jul 1967)
DesignersGiovanni Michelotti (body)
Built atCanley

Engine

Sources for Engine, TR4A (solid axle)

Capacity
One good source.TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13
Engine position
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Block
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinder head
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Valve gear
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Bore × stroke
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Compression ratio
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel system
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cooling
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinder layout
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cylinders
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Ignition
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Cycle
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Lubrication
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Capacity2138 cc
Engine positionFront
BlockCast iron
Cylinder headCast iron
Valve gearOHV, 2 valves per cylinder
Bore × stroke86 x 92 mm
Compression ratio9.0:1
Fuel systemCarburetor
CoolingWater-cooled
Cylinder layoutInline
Cylinders4
FuelPetrol
IgnitionCoil and distributor
CycleFour-stroke
LubricationWet Sump

Performance

Sources for Performance, TR4A (solid axle)

Power
Good sources agree."All cars had 104bhp/2138cc"; rating not stated. TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13; Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; TR Drivers Club, "Early Cars: The TR4A"⁠11
Torque
Good sources agree.Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; TR Drivers Club, "Early Cars: The TR4A"⁠11
Power104 bhp
Torque132 lb ft

Running gear

Sources for Running gear, TR4A (solid axle)

Steering
One good source.TR4 and TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Gearbox
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Gears
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Overdrive
One good source.Optional; TR4 and TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Layout
One good source.Live-axle TR4A. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
Front brakes
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Rear brakes
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Front suspension
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Rear suspension
Several figures in print.Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13
Tyres
One good source.TR4A. Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6
Wheels
One good source.TR4A. Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6
Final drive
One good source.Live-axle TR4A. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
Clutch
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Steeringrack and pinion
GearboxManual
Gears4
OverdriveA-type, on 2nd to 4th
LayoutRWD
Front brakesDisc, 11 in
Rear brakesDrum, 9 in
Front suspensionIndependent, double wishbones, coil springs, telescopic dampers
Rear suspensionlive axle on half-elliptic leaf springs, on brackets added to the new TR4A frame

Rear suspension, TR4A (solid axle)

Several figures in print.

  • live axle on half-elliptic leaf springs, on brackets added to the new TR4A frameGood sources agree: Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3
  • live axle and leaf springsGood sources agree: TR Register, "Triumph TR4 / TR4A Buyers Guide", on the new TR4A frame⁠13
Tyrescross-plies (5.50/5.90-15) as standard; most cars on radials, usually Michelin X 165-15
Wheels4½J x 15 pressed steel; 60-spoke wire wheels optional
Final driveShaft
ClutchDry single plate

Body and chassis

Sources for Body and chassis, TR4A (solid axle)

Body
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Body material
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Seats
One good source.TR4A section. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Chassis material
One good source.The TR4A frame. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
BodyRoadster
Body materialSteel
Seats2
Chassis materialSteel

Dimensions and weight

Sources for Dimensions and weight, TR4A (solid axle)

Length
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Width
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Height
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Kerb weight
One good source.Live-axle car. G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017⁠5
Wheelbase
One good source.TR4A. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Fuel tank
One good source.TR4 and TR4A. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2
Length391.0 cm
Width147.0 cm
Height127.0 cm
Kerb weight2211 lb
Wheelbase223.5 cm
Fuel tank11.75 gal

Contents

Specification: TR4A

Production

Sources for Production, TR4A

Price new
Several figures in print.Triumph Sports Owners Association, Triumph Sports Owners Association Newsletter, March 1965, Mar 1965 (vol. 11 no. 3)⁠9; Motor Sport, "Cornering fast in a Triumph TR4A…" (Standard-Triumph advertisement, with price list), May 1966, p. 49⁠12; Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4
Built
Several figures in print.Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2; Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6; Revington TR, "TR4A: Technical Specification Change Points"⁠10
Price new$2,899 POE East Coast, Gulf ports and Great Lakes; $2,949 West Coast

Price new, TR4A

Several figures in print.

  • $2,899 POE East Coast, Gulf ports and Great Lakes; $2,949 West CoastOne good source: Triumph Sports Owners Association, Triumph Sports Owners Association Newsletter, March 1965, Mar 1965 (vol. 11 no. 3), US, March 1965; IRS $150 extra⁠9
  • £968 4s 7d with purchase taxOne good source: Motor Sport, "Cornering fast in a Triumph TR4A…" (Standard-Triumph advertisement, with price list), May 1966, p. 49, UK, May 1966; hardtop £42 5s 10d extra (OCR)⁠12
  • DM 12,750 DMOne good source: Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF), Germany, new; date not given⁠4
BuiltJan 1965 (start)

Built, TR4A

Several figures in print.

  • Jan 1965 (start)Good sources agree: Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1, first production car CTC50006, 5 Jan 1965⁠2; Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering), from CTC50001 (Piggott, via the VTR)⁠6
  • Jul 1967 (end)Good sources agree: Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1, CTC78684, 11 Jul 1967⁠2; Revington TR, "TR4A: Technical Specification Change Points", last car 10 Jul 1967⁠10

Engine

Sources for Engine, TR4A

Carburettors
Several figures in print.Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3; Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering)⁠6; Revington TR, "TR4A: Technical Specification Change Points"⁠10
CarburettorsZenith-Stromberg 175 CD

Carburettors, TR4A

Several figures in print.

  • Zenith-Stromberg 175 CDOne good source: Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012, at first⁠3
  • SU HS6Good sources agree: Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering), from CTC62191 (Piggott, via the VTR)⁠6; Revington TR, "TR4A: Technical Specification Change Points", from CTC61291⁠10

Contents

Production

Production: how far the sources agree

about 10,000, TR4A (solid axle), of 28,465 TR4As; Graham Robson's estimate
Not yet confirmed.
not known, TR4A (solid axle), "exact numbers are not known"
Good sources agree.
28465, TR4A, home 3,075; export 25,390
One good source.

  1. about 10,000TR4A (solid axle), of 28,465 TR4As; Graham Robson's estimate

    Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2

  2. not knownTR4A (solid axle), "exact numbers are not known"

    Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF)⁠4; Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012⁠3

  3. 28465TR4A, home 3,075; export 25,390

    Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1⁠2; TR Register, "Triumph TR4 / TR4A Buyers Guide"⁠13

Contents

Sources

Every source the site cites is on the sources page.

  • Primarymade at the time, by the maker or by people who were there
  • Referenceserious later work: clubs, specialists, magazines, books
  1. Motor Sport, "Matters of moment, April 1965", Apr 1965, p. 11, p. 11, the drive to Geneva; p. 11. motorsportmagazine.com/archive/article/april-1965/11/matters-of-moment-april-1965 Primary
  2. Graham Robson (essay "15 Years of Evolution"), Triumph TR2 – TR3/3A, TR4/4A – TR5, TR250 1953–1968 Parts & Accessories Catalogue, Rimmer Bros, edn 2.1 (source code TR2512), Part 1, p. 5, Robson's essay: the new frame, IRS and the North American live-axle car; p. 7, the number list; p. 5, "an entirely new type of chassis frame"; p. 7: CTC50006 on 5 January 1965; CTC78684 on 11 July 1967 and CTC78687 on 10 July; the calendar-year ranges and their model-year labels; p. 1, the beam-axle TR4A sold only in North America; p. 5, Robson's "entry-level" TR4A and his estimate; p. 7, "Vehicle Identification"; pp. 5-6, Robson, basic summaries; p. 6, "TR Production Figures: 1953 to 1968"; p. 8, "Service Information"; p. 5, Robson, "15 Years of Evolution". rimmerbros.com/images/PDFs/TR2-5_Part1.pdf Reference
  3. Aaron Severson, "Grandfather's Ax: The Many Evolutions of the Triumph TR4, Part 1: TR4 and TR4A", Ate Up With Motor, 22 Oct 2012, "The Independent TR4"; "The Independent TR4": the ride; IRS dropped on cost for the TR4; IRS on every other model by 1962; the return to profit; "The Independent TR4": the frame; the arms, springs and dampers; the splines; the front suspension and slower steering; the intake manifold and exhaust; about 4% more power; the SUs "possibly for supply reasons"; the grille, lamps, badges, overriders, hood, dashboard and handbrake; the period tests' findings (Motor and Autocar 1965, Car and Driver 1965, Motor Trend 1966); "The Independent TR4": the live-axle cars, Genser-Forman and the $3,000 barrier; "factory figures do not indicate how many"; engine photo caption. ateupwithmotor.com/model-histories/triumph-tr4-tr4a/view-all Reference
  4. Bruno Dwinger, "Geschichte, Typenkunde und Kaufberatung: Standard-Triumph TR4, TR5/TR250 – 'die Michelotti Autos'", TR-Register Deutschland, 2009, 13 pp. (PDF), p. 4, shown in March 1965; p. 4, the call for a softer ride; p. 4, the frame strengthened from the middle back; p. 4, the engine speed of peak power; p. 4, "exact numbers are not known"; p. 4; pp. 4, 11; pp. 3-4; p. 12. tr-register.de/wp-content/uploads/2025/08/Kaufberatung-TR4-und-TR5-und-TR250.pdf Reference
  5. G. William Krause, The Illustrated History of Triumph Sports and Racing Cars, CarTech, 2017, p. 56, the TR4's ride; pp. 57–59, the side rails, the rear crossmember, "the splines had a tendency to jam"; pp. 58–59, the body and cabin; p. 57, Autocar 1965 as quoted; p. 59, a second slower; ch. 3, pp. 57, 59; ch. 3, p. 59. static.summitracing.com/global/images/technicalarticles/sad-ct596.pdf Reference
  6. Vintage Triumph Register, "TR4A" (history, change points and yearly output, buyer's and spotter's guides, numbering), history after Robson: the IRS design from around 1962; "as different, in its own way"; "a much wider frame"; "a massive pressed-steel bridge piece"; camber; Markland's "safe for 120 mph", after Robson; SUs from CTC62191; Strombergs on some later cars; the exhaust; spotter's guide; the bonnet bulge; the Surrey top; wheels and tyres; change points after Piggott: CTC50001, CTC50125, CTC59836, CTC62191, CTC62637; CT cars numbered in sequence; approximate yearly figures; "not as fast on the road as the critics expected", after Robson; the leaf springs on the new frame; "not ever considered reasonable to keep the narrow TR4 chassis"; TR4A page, spotter's guide; TR4A page; TR4A page, numbers; TR4A page, change points. vintagetriumphregister.org/tr4a Reference
  7. Revington TR, "TR4A", "6 universal joints, 3 prop shafts and 2 trailing arms"; "proper catches at the front"; the dealers "eventually saw sense". revingtontr.com/the-tr-series/tr4a Reference
  8. M. L. Twite ("M.L.T."), "Earls Court 1963", Motor Sport, Nov 1963, p. 15, "Triumph have i.r.s. on all their models except the TR4". motorsportmagazine.com/archive/article/november-1963/15/earls-court-1963 Primary
  9. Triumph Sports Owners Association, Triumph Sports Owners Association Newsletter, March 1965, Mar 1965 (vol. 11 no. 3), IRS on the TR4A only; the TR4A's US specification list; the US cars' leather seats, carpet and console; the hood; IRS as an option; "it's a steal"; p. 2. vintagetriumphregister.org/tsoa/TSOA0365.pdf Primary
  10. Revington TR, "TR4A: Technical Specification Change Points", SU from CTC61291; "Twin exhaust system deleted and cross-box introduced"; CT50001; CTC61291; the cross-box exhaust from about CT70000; change-point list. revingtontr.com/the-tr-series/tr4a/technical-specification-change-points Reference
  11. TR Drivers Club, "Early Cars: The TR4A", the engine speed of peak power; the TR4A's exterior and interior changes; the hood; the CT prefix; TR4A page. trdrivers.com/earlycars/tr4A.html Reference
  12. Motor Sport, "Cornering fast in a Triumph TR4A…" (Standard-Triumph advertisement, with price list), May 1966, p. 49, p. 49, the "Hard-top model"; p. 49; p. 49, price list. motorsportmagazine.com/archive/article/may-1966/49/1-cornering-fast-in-a-triumph-tr4a-youre-glad-of-2 Primary
  13. TR Register, "Triumph TR4 / TR4A Buyers Guide", hardtops on the TR4 and TR4A; "not please note the old TR4 frame"; TR4A data; TR4A model summary. tr-register.co.uk/resources/buyers-guide/triumph-tr4-4a Reference
  14. Motor Sport, "Letters from Readers" (the TR4A letters), Mar 1967, p. 55, the editor's note: "The 'A' is a big improvement". motorsportmagazine.com/archive/article/march-1967/55/letters-readers-march-1967 Primary

Contents