The drivetrain upgrades section covers the most sought-after performance and usability improvements for the Midget transmission, from complete gearbox swaps to individual component upgrades, suiting fast-road, sprint, hillclimb, and competition use as well as motorway-cruising road cars.
Five-Speed Conversion
A five-speed gearbox conversion is one of the most transformative upgrades available for the Midget. The addition of a fifth overdrive gear significantly reduces engine revs at cruising speed, typically by 15 to 20% at motorway speeds, improving refinement, reducing mechanical noise, and lowering fuel consumption on longer journeys. The conversion replaces the original four-speed gearbox with a five-speed unit and the necessary adaptor components, designed to fit within the existing transmission tunnel without bodywork modification. The gear lever position remains similar to the original, and the clutch hydraulic system is retained.
Five-Speed Benefits by Model
The conversion is particularly valuable for 1500 cars, where the engine's lower rev ceiling means the standard four-speed gearbox leaves the engine working harder than necessary at sustained cruising speeds. For 1275cc cars, the fifth gear is equally beneficial but the improvement in refinement is perhaps even more noticeable, as the A-Series engine is more vocal at high revs and the reduction in cabin noise on longer journeys is significant.
Limited Slip Differential
A limited slip differential replaces the standard open differential and distributes torque more evenly between the two rear wheels when one begins to lose traction. With the standard open differential, if one rear wheel loses grip, whether through a wet surface, an uneven road, or hard cornering, all the engine's torque goes to the spinning wheel while the gripping wheel receives none. A limited slip unit prevents this by mechanically linking the two wheels, ensuring both receive drive even when traction conditions differ.
Limited Slip Applications
The LSD upgrade is particularly beneficial for competition use (hillclimbs, sprints, and circuit work), but also offers a noticeable improvement in wet-weather grip for road-driven cars where the standard open diff can otherwise spin the inside wheel out of slow corners or on damp surfaces. The limited slip unit fits within the standard axle case and uses the existing crown wheel and pinion, so it can be combined with either the 3.9:1 or 3.7:1 final drive ratio without further axle work.
Uprated Clutch Components
Uprated clutch components including heavier-duty driven plates and competition-specification clutch covers are available for engines producing significantly more power than standard, Stage II builds, supercharged engines, or any application where the standard clutch may slip under torque. For most road-driven Midgets, the standard clutch kit provides adequate clamping force and a comfortable pedal weight, and an uprated clutch is generally unnecessary unless the engine has been extensively modified.
Stainless Braided Clutch Hose
A stainless steel braided clutch hose replaces the standard rubber flexible hose and eliminates the flex that can occur in an ageing rubber hose, providing a firmer and more consistent pedal feel. This is a worthwhile upgrade even on a standard-specification car, as the original rubber hose can expand under hydraulic pressure after years of service, reducing the effective throw of the slave cylinder and contributing to the gradually deteriorating clutch action that owners often misdiagnose as cylinder seal failure.