Triumph TR5, TR250 and TR6 (1967 to 1976)

Why people buy one

• A smooth, torquey 2.5-litre six with a distinctive sound, and independent rear suspension on every car.
• Triumph promoted the TR5 as Britain's first production sports car with petrol injection, and fewer than 3,000 were built.
• The TR6 is the best-selling of the separate-chassis TRs, with 91,850 built, so there is a wide choice of cars.
• Body-on-frame construction is easy to work on, and Hagerty UK says parts are plentiful.

What to weigh up

• Identity matters. TR5s and injected TR6s (CP, then CR) are more sought after than carburettor TR250s and US TR6s (CD, CC, then CF), and carburettor cars can be fitted with injection, or injected cars with carburettors.
• Classics World notes six-cylinder engines have been fitted to TR4s and TR4As, so a claimed TR5 must have a CP commission number.
• Most TR6s went to North America, and many have come back; check whether a right-hand-drive car was converted and ask for the paperwork.
• The Lucas injection system needs a specialist to set up; poor maintenance causes rich running and fuel vaporisation, though uprated pumps are common.
• The IRS has limited travel, the ride is bouncy and driveshaft splines and joints wear.
• The TR7 and TR8 are a different, monocoque design and are not covered here; the four-cylinder TR4A has its own profile.

Where they rust

• Chassis rails, which trap moisture inside; check the inside corners and the cruciform where the rails meet.
• The rear trailing arm mountings and the pressing over the differential, which rust from the inside out.
• Differential mountings, which can crack or break under hard acceleration.
• Outriggers, the front crossmember and the engine and gearbox mountings.
• Sills, floors and B-posts; a gap opening up at the B-post suggests a sagging chassis.
• On the TR6, the join between the rear wings and rear deck, where three layers of metal trap dirt.
• Front wings behind the headlamps, the bonnet leading edge, the rear wing tips and the rear lip of the boot lid.
• Boot floor.

Mechanical weak spots

• Engine: crankshaft thrust washers wear; with the clutch pressed, look for fore and aft movement at the crank pulley, as excess endfloat can wreck the engine. Low oil pressure and smoke point to a rebuild.
• Injection: ignition and camshaft timing and intact vacuum hoses are vital, and the original fuel pump is a known weak point; many cars have an uprated pump.
• Gearbox: layshaft bearings wear, causing noise in first, second and third gears, and clutch release bearings wear quickly.
• Rear axle: clunks on take-off point to worn driveshaft splines, universal joints or failed differential mounts; the differential often leaks.
• Steering and front suspension: trunnions need oil and regular attention, and rubber rack mounts soften with age.
• Brakes are front discs and rear drums. Electrics suffer from poor earths and aged wiring, so check every light and the wipers.

At a Mathewsons viewing

• Check the commission number against the V5C. TR5s start CP and TR250s CD; TR6 injection cars are CP then CR, and TR6 carburettor cars are CC then CF.
• On the TR5 and earlier TR6s the commission number is also stamped on the nearside front inner wheelarch; check it matches the plate, and note the engine number so it can be compared with a Heritage Certificate.
• Ask for a British Motor Museum Heritage Certificate, which shows the original engine number, build and despatch dates, colour and equipment, so a converted TR250 or carburettor TR6 shows up.
• With a torch, look under the car at the rear trailing arm and differential mountings, the chassis rails and outriggers, and the sills; lift the carpets and boot floor for damp or rot.
• Open the bonnet and look for the injection metering unit or twin carburettors, fuel leaks and wiring condition; if staff start the car, listen for knocks and watch the oil pressure, but do not assume it will be started.

Parts, specialists and clubs

Seen on Bangers & Cash

• Triumph TR6 (Bangers & Cash series 2, episode 2, First shown February 2020)
• Triumph TR6 (Restoring Classics series 7, episode 4, First shown October 2025 on U&Yesterday)

Sources

• Buyers Guide: Triumph TR6 (Hagerty UK), 12 November 2014
• Triumph TR6 buyer's guide (Classics World), 22 May 2026
• Triumph TR5 buyer's guide (Classics World), 17 July 2023
• Triumph TR6 buyer's guide (TR Register), accessed 14 October 2026
• Triumph TR250 and TR6 vehicle identification (Moss Motors), accessed 14 October 2026
• Heritage Certificates (British Motor Museum), accessed 14 October 2026
• Triumph TR5 (Wikipedia), accessed 14 October 2026
• Triumph TR6 (Wikipedia), accessed 14 October 2026