Harley-Davidson XG500 Street 500 Turn Signal Bulb Size
The Harley-Davidson XG500 Street 500 uses a 5008 bulb size for front turn signals and either P21W or 5008 bulb size for rear turn signals. The replacement chart covers 2015 through 2020 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 two bulb types specified for the Harley-Davidson XG500 Street 500 are the 5008 and the P21W. Both are single-filament bulbs sharing the BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm base width.
The 5008 follows the ANSI standard used in the United States and Canada, while the P21W follows the ECE standard applied in Europe and other world markets. Despite their different regulatory origins, both operate on a 12V electrical system.
The P21W is rated at 21W, whereas the 5008 is a lower-wattage variant of the 1156 bulb. This wattage difference is a relevant fitment consideration, as substituting one for the other may affect turn signal flash rates, which are typically governed by load-sensitive flasher relays.
The shared BA15s base between the 5008 and P21W means both bulbs are physically interchangeable in terms of socket fit. However, the wattage difference means electrical compatibility is not guaranteed without verifying the flasher relay tolerance of the specific vehicle.
For the front turn signal position, the 5008 bulb is specified for the 2015-2016 model years. No front turn signal bulb change is recorded beyond that range in the provided specifications.
The rear turn signal position uses the 5008 for the 2015-2016 model years and transitions to the P21W for the 2017-2020 model years, indicating a change in the bulb standard applied to that position across the production run.
Because the front and rear turn signals share the same bulb type in 2015-2016 but diverge in later years, a 2017-2020 XG500 Street 500 requires two different bulb types depending on whether the front or rear position is being serviced.