Back Axle Parameters of the TR8

Only one type of rear axle was employed in the TR8. It had the same casing as its companion in the five speed TR7.


The rear axle assembly comprises a live rear axle. Drive to rear wheels through hypoid bevel gears, two pinion differential and semi-floating axle shafts using taper roller bearings. A malleable cast-iron hypoid housing with pressed in steel tubes and a pressed steel rear cover.

The crown wheel and pinion ratio (often known as the diff ratio) equates to 3.08:1.

This is arrived at by the number of teeth (37) on the crown wheel divided by the number of teeth (12) on the pinion giving a figure of 3.08.

This was the only ratio offered for the TR8, including the automatic version, giving the car a balance between speed, acceleration and fuel consumption.

As the casing is identical to that of the TR7, two other "diff ratios" could be used from the TR7, namely, 3.90:1 and 3.45:1, by merely swapping axles. However, this would upset the overall balance of the car. A further ratio, 2.84:1, can be found in the Rover SD1 Vitesse but would involve a complete strip and rebuild of both axles and a great deal of technical expertise.