BMW Motorcycle R1100S front and rear turn signal bulbs use 12496, PY21W, and P21W bulb sizes for replacement specifications. The replacement chart covers 1998 to 2005 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The BMW Motorcycle R1100S turn signal specifications cover model years 1998-2005 for both front and rear positions.
Three bulb types appear across these specifications: 12496, PY21W, and P21W. All three operate at 12V, and both PY21W and P21W are rated at 21W.
The P21W is an ECE-standard single-filament signalling bulb fitted with a BA15s bayonet base. It is specified for use without a clear lens across all model years in both the front and rear turn signal positions.
The PY21W is an ECE-standard single-filament amber bulb fitted with a BAU15s bayonet base. It is specified exclusively for configurations with a clear lens, where the amber tint of the bulb itself provides the required signal color.
The 12496 is a Philips/Osram part number designating a 12V halogen bulb for specialty applications. It is also specified only for clear lens configurations throughout the model range.
The BA15s base of the P21W and the BAU15s base of the PY21W are not interchangeable. The BAU15s has offset pins, while the BA15s has straight pins, meaning the two bulbs cannot be substituted for one another despite sharing the same wattage and voltage rating.
The lens type on the R1100S determines which bulb is applicable. Clear lens housings call for either the PY21W or the 12496, while non-clear lens housings call for the P21W.
The 12496 and PY21W are listed together under clear lens fitment across multiple years, indicating they serve as alternatives to one another in that configuration rather than as separate requirements.
The front turn signal for 2003 and 2001 does not include a PY21W listing under the clear lens option, while the 12496 remains listed for those years, making the 12496 the sole clear-lens alternative to the P21W in those model years for the front position.
The rear turn signal for 1999 and 1998 similarly lists only the 12496 alongside the P21W, without a PY21W entry, a pattern also present in the 1998 front turn signal specification.