The Rolls-Royce Silver Cloud front and rear turn signal bulb sizes include 1157, P21W, and 1141 options for this luxury vehicle model. The replacement chart covers 1955 to 1965 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Rolls-Royce Silver Cloud front and rear turn signal specifications reference three distinct bulb types across the 1955-1965 model years: the 1157, the 1141, and the P21W.
The 1141 is the most frequently specified bulb across both front and rear positions in the Silver Cloud lineup. It follows the ANSI standard used in the United States and Canada, operates at 12V with a 21W output, and uses a BA15s single-contact bayonet base.
The 1157 is a dual-filament bulb rated at 21W and 5W on its respective filaments, operating at 12V with a BAY15d bayonet base. The BAY15d base features offset pins to prevent incorrect installation, distinguishing it physically from single-filament bayonet types.
The P21W follows the ECE standard used in Europe and internationally. It is a single-filament bulb rated at 12V and 21W, using a BA15s bayonet base, the same base type as the 1141.
Although the P21W and 1141 share the BA15s bayonet base and identical voltage and wattage ratings, they originate from different standardization systems. The P21W is an ECE-standard part and the 1141 is an ANSI-standard part, and substitution between them warrants verification of physical and electrical compatibility before use.
The 1157 uses a BAY15d base, which is not physically interchangeable with the BA15s base found on both the 1141 and P21W. Attempting to fit a 1157 into a BA15s socket, or vice versa, is not possible without modification.
The Rolls-Royce Silver Cloud front turn signal position used the 1141 from 1955-1961, transitioned to the P21W for 1962, and then shifted to the 1157 for 1963-1965.
The rear turn signal position on the Silver Cloud used the 1141 for 1955-1957, the P21W for 1958-1961, returned to the 1141 for 1962, and then used the 1157 for 1963-1965.
For the 1963-1965 model years, the front and rear turn signal positions share the same 1157 specification, while earlier years show differing bulb types between the two positions within the same model year.
The 1962 Silver Cloud presents a notable split fitment, with the front turn signal requiring a P21W and the rear requiring a 1141. Despite both using a BA15s base, they are sourced from different standards bodies, and the two positions are not served by a single common part number in that year.