Triumph TR3B
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| Triumph TR3B | |
|---|---|
| Manufacturer | Triumph Motor Company |
| Production | 1962 |
| Predecessor | Triumph TR3A |
| Successor | Triumph TR4 |
| Class | Sports car |
| Engine | 2138 cc Straight-4 |
The Triumph TR3"B" was produced by the Triumph Motor Company (Standard Motor Company) in 1962. It followed the TR3A and was offered concurrent with the TR4, which started production in 1961. In fact, the TR3"B" was a special short production run produced in response to dealer concerns that the buying public might not welcome the TR4.
The TR3"B" is not actually labeled as such, but the model name is common usage. It had the body of the TR3A, but the 2,138 cc. engine and all synchromesh transmission of the TR4. The gearbox has an excellent feel. The engine is a straight 4, push rod, 3 bearing, with wet liners. It had 9:1 compression, was very rigid and had wonderful slow running and clutch feel. It was fitted with two H6 SU carburettors. It had 105 hp (78 kW) at 4,650 rpm. and 127 ft·lbf (172 Nm) of torque at 3,350 rpm. It got around 20 to 30 miles per US gallon. The top speed was limited to about 110 mph (177 km/h). by the gear ratio, unless it had overdrive. Electrically triggered overdrive (Laycock-de-Normanville Type A) was available as an option and operated on 2nd, 3rd, and 4th gears. Appearance was identical to the TR3A, and as such very similar to the TR3, except for a wider grill and door handles.
The suspension was by double A-arms, manganese bronze trunnion, coil springs and tube shocks at the front, optional anti-roll bar, and with worm and peg steering. Unlike MGs of the same period, the steering mechanism and linkage had considerable play and friction, which increased with wear.
The rear was conventional leaf springs, with solid axle and lever shocks, except that the (box) frame rails were slung under the axle (underslung*). The wheels were 15 inch diameter x 4.5" width (increased from 4" after the first few TR2s), with 48 spoke wire wheels optional. Wire wheels were usually painted, either body color or argent (silver), but matte chrome and bright chrome were also available. It had front disk brakes (the TR was the first production car to feature these) and rear drums with no power assist.
It weighed 2,137 pounds (969 kg) which was significantly more than the Morgan +4 and the "Bath Tub" (pre-911) Porsches, but not much more than the MGA and MGB. All except the Morgan, which shared the same engine, were substantially less powerful.
Though, under most conditions it was very responsive and forgiving, it had a some handling vices. The chassis, which it shared with the TR2, TR3, TR3A and TR4 had limited wheel travel, and the car was somewhat tall and narrow for a high performance sports car. As a result, on very hard cornering, the frame might come up and suddenly pick up the outside rear wheel, causing sudden over-steer due to the increased load on the outside rear tire. This was particularly true with increasingly common radial tires. The original TR2/3/3A suspension was built with older, bias ply tire designs in mind.
The TR3"B" is a true roadster, designed for sunny weather with removable rain protection. It has a convertible top (hood) that snaps on and off and removable side curtains, allowing very low doors with padding to rest one's arm on. There are holes in the floor, with rubber plugs, so that the originally supplied jack might used from inside the car, as did the Jaguar XK 120. The optional heater was poor and the shut-off valve was under the hood (bonnet). A third person could get behind the seats, if absolutely necessary.
- Frame under axle was pioneered by the American Motor Car Co. 1907 American Underslung.
