The 105R featured a "Roverdrive" automatic transmission. This unit was designed and built by Rover and at the time was the only British-built automatic transmission. Others had bought in units from American manufacturers such as Borg-Warner. This unit was actually a two-speed automatic (Emergency Low which can be selected manually and Drive) with an overdrive unit for a total of three forward gears. The 105S made do with a manual transmission and Laycock de Normanville overdrive incorporating a kick-down control. The 105S could reach a top speed of 101 mph (163 km).