Although the car was usually supplied as an open two-seater, an occasional rear seat and bolt-on steel hard top were available as extras.
The car is powered by a 1991ccstraight-fourOHVengine initially producing 95bhp (71kW; 96PS), an increase of 5hp over the TR2 thanks to the largerSU-H6 carburettors fitted. This was later increased to 100bhpat 5000rpm[5]by the addition of a "high port" cylinder head and enlarged manifold. The four-speedmanual gearboxcould be supplemented by an overdrive unit on the top three ratios, electrically operated and controlled by a switch on the dashboard. In 1956 the front brakes were changed from drums to discs, the TR3 thus becoming the first British series production car to be so fitted.[8]
The suspension is by doubleA-arms,manganesebronzetrunnion, coil springs and tube shocks at the front, optional anti-roll bar, and with worm and peg steering. UnlikeMGsof the same period, the steering mechanism and linkage have considerable play and friction, which increase with wear.
The rear is conventionalleaf springs, with solid axle and lever arm dampers, except that the (box) frame rails are slung under the axle. The wheels are 15 inches in diameter and 4.5 inches wide (increased from 4 inches after the first fewTR2s), with 48-spoke wire wheels optional. Wire wheels were usually painted, either body colour or argent (silver), but matt chrome and bright chrome were also available. The frontdiscordrumbrakes and rear drums have no servo assistance.
The TR3's weight is significantly more than theMorgan +4and thePorsche 356, but not much more than theMG-AandMG-B. All except the Morgan, which shares the same engine, are substantially less powerful as is theSunbeam Alpine.
Under most conditions the car is very responsive and forgiving, but it has somehandlingissues. The chassis, which is shared by the TR2, TR3, TR3A and TR4 has limited wheel travel. As a result, on very hard cornering, the inside rear wheel can lift, causing sudden over-steer due to the increased load on the outside rear tyre. This is particularly true with radial tyres; the original TR2/3/3A suspension was built with older, crossply tyre designs in mind. The wheel lifting is more sudden than that of other cars, because it is caused by coming to the end of the suspension travel while there is still load on the tyre, so the load on the other (outside) rear wheel is a discontinuous function of cornering load, rather than just changing slope.
The TR3 is a true roadster, designed for sunny weather but with removable rain protection. It has a convertible hood (UStop) that snaps on and off and removable side curtains, allowing very low doors with padding for the driver's arm to rest on. There are holes in the floor, with rubber plugs, so that the originally supplied jack might be used from inside the car, as did theJaguar XK120. The optional heater is poor and the shut-off valve is under the bonnet (UShood). A third person can be carried behind the seats.
Some 13,377[9]examples of the original "pre-facelift" TR3 were produced, of which 1,286 were sold within the UK; the rest were exported mainly to the USA. As of Q1 2011 there were approximately 826 licensed and 115SORNTR3/3as registered with theDVLA.[10]
TR3 specifics[edit]A hardtop car with overdrive tested by the British magazineThe Motorin 1956 had a top speed of 105.3mph (169.5km/h) and could accelerate from 0–60mph (97km/h) in 10.8 seconds. A fuel consumption of 27.1 miles per imperial gallon (10.4L/100km; 22.6mpg-US) was recorded. The test car cost £1,103 including taxes.[5]
Other figures recorded included: