Triumph Tina That was then...
When The Motorcycle took possession of a Tina to test in March 1962, it wasn’t just the automatic gearbox its testers found fascinating: they also discovered that it had plastic parts. It was truly a glimpse into the future!
Tina comes to town
Triumph surprise: a 100cc Miniscooter with Automatic Transmission
What was that? Just a little scooter, nothing to get excited about? You don’t know Tina, that pert mam’selle from Meriden. Come and be introduced. No clutch lever, no gear pedal? That’s right; just throttle and brakes – and an ingenious automatic transmission. And Triumph have even put the rear brake pedal in the middle where it can be operated by either foot. Easy as riding a bicycle and only a little more costly.
That switch, marked Start and Drive, rearward of the speedometer, is a safety device. As the engine speed rises, so centrifugal force causes the driving pulley to start transmitting power to the rear wheel (you’ll see how later). But you don’t want the machine to take off before you are properly aboard. So you flick the switch over to Start, press down the left mounted starter pedal and the engine fires. But while it will run at a tickover, no amount of throttle blipping will make it speed up – for an electrical cut-out prevents it from doing so. No premature take up of the drive therefore.
Comfortably settled on the nice and low (only 26in high) dual-seat, you can flick back to Drive, open the throttle and that’s it, away as smoothly as you like, the automatic transmission system of a sturdy V belt and expanding pulleys adapting itself to changes in engine speed to provide the most suitable gear ratio between limits of 14.75 and 5-to-1.
Tina is crammed from end to end with interesting features. Look at the box section frame beam, for example, through which air to the carburettor is drawn from a little grille just below the 16.5in long steering head. Study the suspension system – trailing link fork front, controlled by rubber in compression and the engine, transmission and rear wheel pivoted as a single unit by a single damper.
But the engine is orthodox enough. It is a straightforward two-stroke of 99.75cc (50.4x50mm bore and stroke) which, at 7-to-1 compression ratio, develops 4.5bhp at 5000 rpm. At each side, the crankshaft is carried in a ball bearing; the big end has a caged roller bearing. When fully run-in the engine will operate happily on a 30-to-1 petroil mixture.
The cast-iron cylinder barrel and light alloy head are fan cooled from the Wipac flywheel magneto (which incorporates directlighting coils). As mentioned earlier the kickstarter pedal is on the left; it operates in a forward direction, and its quadrant engages with a pinion on the engine shaft.
Ingenuity is evident in the design of the driving pulley. The inner flange cannot move laterally but the outer flange can move inward, causing the driving vee-belt to ride up the flange slopes and so raise the gear ratio. Movement of the pulley flange is controlled by the engine speed in this way. Splined to the driving shaft is a light-alloy spider, embracing three radial tracks, in each of which is a steel ball; matching tracks are formed on the outer face of the movable pulley flange. As the speed is increased, so the balls are flung outward along the cam tracks, and a wedge action forces the pulley flanges laterally inward against the pressure of three light springs bearing against a pressure plate. Conversely, as the engine speed falls, so the balls return down the pulley tracks, while the light springs pull the flange outward once more.
When the engine is idling, there is clearance between the pulley flanges and the sides of the belt (which is supported on a ball bearing hub) and no drive takes place. So that condition is maintained, a pivoted arm bears against the spring pressure plate. This arm actuates a set of contact points, energised when the safety switch is in the Start position. Any movement of the pulley flange – and hence of the pressure plate – causes the points to close, thus interrupting the ignition circuit.
Drive is by a Goodyear V belt, of rubber reinforced with nylon cord, to a countershaft pulley with a spring loaded inner flange; the spring loading is necessary, since any adjustment of the driving pulley would otherwise stretch the belt. Integral with the countershaft is a helical tooth reduction gear, in mesh with a larger diameter pinion keyed to the rear hub shaft. No outer cover is provided for the belt guard (tests have shown that the scooter will run even through deep snow without ill effect) but the reduction gears are housed in an oil bath, light alloy casing bolted to the rear of the box section, pressed steel pivoted arm.
The carburettor is an Amal type 32, the intake of which is coupled to the frame beam by a short rubber hose. A choke control is mounted concentrically with the pull-out fuel tap on the left of the body; on the same side a float-chamber tickler extension protrudes upward through the metal panelling. Forming the dual-seat base is a 1.5 gallon fuel tank. The filler neck protrudes through the rear of the seat.
Wheel hubs are supported on the left, and embody 5in diameter brake drums. Wheels are of split-rim disc pattern, each secured by three studs and carrying a 3.50x8in Avon tyre. The springing medium for the front wheel comprises two rubber buffers in compression, respectively of hard and soft mix to provide a varying rate, plus a rebound buffer.
Bodywork, footboards and weathershield are of pressed steel but a novelty is the helmet type mudguard; it is a PVC moulding. The neat handlebar cover, a steel pressing, affords a mounting for the 4in diameter Wipac headlamp and the 60mph speedometer. The finish is in lilac.
On the road the little Triumph proved a charming companion, with no vices and capable of speeds in the region of 40mph. To a hardened motorcyclist, the absence of a clutch lever and the lack of engine braking (snapping the throttle shut, of course disengages the drive) were disconcerting at first, but Tina is not aimed at the experienced rider. Instead she offers twowheel motoring with comfort and weather protection, in its simplest form; and at that she’s virtually irresistible.
Makers are the Triumph Engineering Co Ltd, Meridien Works, Allesley, Coventry. Price is £76 3s 6d and its total price (which includes British purchase tax) is £93 9s. In course of preparation is a number of accessories, including a shopping bag hook, windscreen and front mounted carrier basket, prices of which will be announced later.
Tina, that pert mam’selle from Meriden. Come and be introduced.