BMW Motorcycle R50/5 front and rear turn signal bulbs utilize a P21W size across all applications. The replacement chart covers 1969 to 1973 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 BMW Motorcycle R50/5 uses the P21W bulb type for both front and rear turn signals across all model years from 1969-1973.
The P21W is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its dedicated turn signal application on the R50/5.
P21W bulbs operate at 12 volts and consume 21 watts, placing them in the standard range for incandescent automotive signalling applications.
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 single-contact base is distinct from the BA15d double-contact base; substituting a BA15d bulb in a BA15s socket is not compatible due to the differing contact configurations.
The P21W is an ECE-rated bulb, meaning it conforms to the Economic Commission for Europe lighting standard, a specification recognized across European and many worldwide markets.
The uniform use of the P21W across both front and rear positions means the R50/5 requires only one turn signal bulb type throughout the entire motorcycle.
Because the front and rear turn signal specifications are identical across all five model years of the R50/5, no year-specific distinction is necessary when sourcing replacement P21W bulbs for this model.