BMW Motorcycle R1150R Roadster Turn Signal Bulb Size
BMW Motorcycle R1150R Roadster front and rear turn signal bulbs use a 12496 PY21W bulb size. The replacement chart covers 2002 to 2006 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 PY21W is an ECE-standardized single-filament amber bulb operating at 12V and 21W, fitted with a BAU15s bayonet base. The BAU15s base uses offset pins to prevent incorrect installation of non-amber bulbs in amber-designated sockets.
The 12496 is a Philips/Osram part number designating a 12V halogen bulb intended for specialty automotive applications. It is not an ECE or SAE universal standard designation, meaning fitment is tied to that specific manufacturer's catalog reference.
The BMW Motorcycle R1150R Roadster front turn signal uses the PY21W for model years 2002-2004 and transitions to the 12496 for 2005-2006.
The rear turn signal specification shows a mixed pattern across the same production span. The PY21W appears in 2002 and 2004, while the 12496 appears in 2003 and again in 2005-2006.
Because the front and rear positions do not always share the same bulb type within a given model year, the two positions require independent verification before replacement. For example, in 2004 both positions call for the PY21W, while in 2003 the front uses the PY21W and the rear uses the 12496.
The BAU15s base of the PY21W is physically distinct from the more common BA15s base. The offset pin arrangement means a BA15s bulb will not seat correctly in a BAU15s socket, making the two types non-interchangeable despite their similar appearance.
Both the PY21W and the 12496 operate on a 12V electrical system, which is consistent with the standard voltage architecture found on production motorcycles of this era.
The amber color of the PY21W is built into the glass envelope rather than produced by a colored lens, a construction method required under ECE regulations to ensure consistent signal color output regardless of the fixture housing.