Specifications from the official Triumph TR4 Workshop Manual. TR4A differences noted where applicable.
Engine
| Number of cylinders | 4 |
| Bore | 3.386 in. (86 mm.) |
| Bore (Special Order) | 3.268 in. (83 mm.) |
| Stroke | 3.622 in. (92 mm.) |
| Cubic capacity | 130.5 cu. in. (2,138 cc.) |
| Cubic capacity (Special Order) | 121.5 cu. in. (1,991 cc.) |
| Compression ratio | 9 : 1 |
| Valve rocker clearances (cold) | 0.010 in. (0.254 mm.) |
| Firing order | 1, 3, 4, 2 |
Performance Data
| B.H.P. (TR4 nett) | 100 at 4,600 r.p.m. |
| Torque (TR4) | 1,520 lb. in. at 3,350 r.p.m. |
| B.H.P. (TR4A nett) | 104 at 4,700 r.p.m. |
| Torque (TR4A) | 1,590 lb. in. at 3,000 r.p.m. |
Lubrication
| Oil pump type | Hobourn-Eaton eccentric rotor |
| Oil filter | Purolator / A.C. Delco / Tecalemit full flow (replaceable element) |
| Release pressure | 70 lb./sq. in. (4.921 kg./sq. cm.) |
Ignition
| Contact breaker gap | 0.015 in. (0.4 mm.) |
| Spark plugs (normal) | Lodge CNY |
| Spark plugs (high speed) | Lodge HN |
| Spark plugs (competition) | Lodge 2HN |
| Spark plug gap | 0.025 in. (0.64 mm.) |
| Ignition timing | 4° B.T.D.C. (basic setting) |
Cooling System
| Circulation | Pump with bypass |
| Thermostat opening | 70°C (158°F) |
| Thermostat fully open | 85°C (185°F) |
| Filler cap pressure | 4 lb./sq. in. (0.28 kg./sq. cm.) |
Fuel System
| Carburettors (TR4) | Twin S.U. H6, Needle SM |
| Carburettors (TR4A) | Twin Stromberg 175 CD |
| Air cleaners (TR4) | Wire gauze type |
| Air cleaners (TR4A) | Replaceable paper elements |
| Fuel pump | A.C. mechanical with filter and sediment bowl |
Clutch
| Type (TR4) | Borg & Beck 9 in. single dry plate, hydraulic operation |
| Type (TR4A) | Borg & Beck diaphragm spring, 8.5 in. diameter |
Gearbox
| Type | 4 forward speeds and reverse, synchromesh on all forward gears |
| Top (with O/D) | 0.82 (overall 3.034 with 3.7 axle) |
| Top | 1.0 (overall 3.7) |
| 3rd (with O/D) | 1.09 (overall 4.02) |
| 3rd | 1.325 (overall 4.9) |
| 2nd | 2.01 (overall 7.44) |
| 1st | 3.139 (overall 11.61) |
| Reverse | 3.223 (overall 11.93) |
Rear Axle
| Type (TR4) | Hypoid bevel gears, semi-floating axle shafts, taper roller bearings |
| Type (TR4A I.R.S.) | Final drive unit rubber mounted |
| Ratio | 3.7 or 4.1 : 1 |
Brakes
| System | Girling hydraulic |
| Front | Caliper disc |
| Rear | Drum (leading and trailing shoes), 9 in. x 1.75 in. |
Steering
| Type | Rack and pinion, telescopic steering column |
| Caster angle | 3° |
| Camber angle | 2° (static laden) |
| King pin inclination | 7.5° |
| Front wheel alignment | Parallel to 1/8 in. (3.18 mm.) toe-in |
| Turning circle | 33 ft. (10 m.) |
Suspension
| Front | Independent with wishbones, coil springs, telescopic dampers, taper roller hub bearings |
| Rear (TR4) | Wide semi-elliptic springs, piston type dampers |
| Rear (TR4A) | Independent rear suspension available |
Dimensions
| Wheelbase | 7 ft. 4 in. (224 cm.) |
| Track — front (disc wheels) | 4 ft. 1 in. (124.5 cm.) |
| Track — rear (disc wheels) | 4 ft. 0 in. (122 cm.) |
| Track — front (wire wheels) | 4 ft. 2 in. (127 cm.) |
| Track — rear (wire wheels) | 4 ft. 1 in. (124.5 cm.) |
| Ground clearance (static laden) | 6 in. (15.24 cm.) |
| Overall length | 12 ft. 10 in. (391 cm.) |
| Overall width | 4 ft. 9.5 in. (146 cm.) |
| Overall height | 4 ft. 2 in. (127 cm.) |
Weights
| Dry (excluding extra equipment) | 2,128 lb. (965 kg.) |
| Complete (including fuel, oil, water, tools) | 2,240 lb. (1,015 kg.) |
Capacities
| Engine oil (from dry) | 11 imp. pints (13.2 U.S. pints, 6.25 litres) |
| Engine oil (drain and refill) | 10 imp. pints (12 U.S. pints, 5.7 litres) |
| Gearbox | 1.5 imp. pints (1.8 U.S. pints, 0.8 litres) |
| Gearbox with overdrive (from dry) | 3.5 imp. pints (4.2 U.S. pints, 2.0 litres) |
| Gearbox with overdrive (drain and refill) | 2.75 imp. pints (3.3 U.S. pints, 1.6 litres) |
| Rear axle | 1.5 imp. pints (1.8 U.S. pints, 0.8 litres) |
| Cooling system | 13 imp. pints (15.7 U.S. pints, 7.39 litres) |
| Cooling system with heater | 14 imp. pints (16.8 U.S. pints, 8.0 litres) |
| Fuel tank | 11.75 imp. gallons (14 U.S. gallons, 53.5 litres) |
Electrical
| Battery | 12 volt, 51 amp. hr. |
| Control box | Model RB.106-2 |
| Generator | Model C40-1 |