BMW Motorcycle R75/7 front and rear turn signal bulbs utilize a P21W size across both positions. The replacement chart covers 1976 to 1977 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the sole bulb type specified for the BMW Motorcycle R75/7, covering both the front and rear turn signals across the 1976-1977 model years.
The P21W is a single-filament bulb, meaning it serves one lighting function only, which in this application is turn signaling.
The P21W operates at 12 volts and draws 21 watts, a wattage level standard for turn signal applications where sufficient brightness and flash visibility are required.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base.
The BA15s base is a single-contact design, which corresponds directly to the single-filament construction of the P21W bulb.
The P21W is an ECE-rated bulb, meaning it conforms to the Economic Commission for Europe lighting regulations, a standard adopted across Europe and numerous other markets worldwide.
Because the front and rear turn signals on the R75/7 share the same P21W specification, the bulbs are physically interchangeable between positions.
Substituting a dual-filament bulb with a BA15d base in place of the BA15s P21W would not be compatible, as the single-contact socket of the R75/7 does not accommodate a dual-contact base.