The BMW Motorcycle K1300GT uses an H21W bulb size for front turn signals and a P21W bulb size for rear turn signals. The replacement chart covers 2009 to 2010 model 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 BMW Motorcycle K1300GT uses two distinct bulb types across its turn signal positions: H21W for the front and P21W for the rear, both rated at 12V and 21W.
Both the H21W and P21W are single-filament bulbs, meaning each serves a dedicated signalling function rather than combining multiple lighting roles within one unit.
The H21W bulb follows the ECE standard, giving it recognized fitment compatibility across European and worldwide markets.
The H21W uses a BAY9s base, which is an offset pin bayonet mount. This base type is less common than standard bayonet fittings, and substituting a bulb with a different base would result in an incompatible fit.
The P21W also follows the ECE standard and operates at the same 12V, 21W rating as the H21W, though the two bulbs are not interchangeable due to their different base types.
The P21W uses a BA15s bayonet base, a single-contact fitting with pins positioned symmetrically. This differs from the BAY9s base of the H21W, making the front and rear turn signal bulbs physically non-interchangeable despite sharing identical wattage and voltage ratings.
The K1300GT front turn signal position calls for the H21W across the 2009-2010 model years, with no variation in specification between those years.
The rear turn signal position on the K1300GT likewise specifies the P21W consistently across the 2009-2010 model years.