The Ducati ST4 front and rear turn signal bulbs utilize 232 and 5008 sizes. Replacement specifications in the chart span 1999 to 2005 for this motorcycle model.
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 across the Ducati ST4 turn signal positions are the 232 and the 5008, both of which conform to ANSI standards applicable to the US and Canadian markets.
The 232 is a festoon-style bulb with an SV8.5 base, rated at 12V and 3W. Festoon bulbs are cylindrical in form and mount by contact pressure at each end rather than by a socket base.
The 5008 is a single-filament bulb with a BA15s bayonet base, rated at 12V. The BA15s designation indicates a single-contact bayonet fitting with a 15mm collar, which locks into its socket with a twist.
The 5008 is a lower wattage variant of the 1156 bulb. While the two share the same BA15s bayonet base and are physically interchangeable in terms of fitment, their wattage ratings differ, making them non-equivalent replacements in applications where wattage is a factor.
For the front turn signal on the Ducati ST4, the 2000-2002 model years use the 5008, while 1999 and 2003 use the 232. These two positions on the same motorcycle require different bulb types depending on the year.
For the rear turn signal, the 5008 and 232 alternate across model years without a consistent pattern, meaning the front and rear positions do not always share the same bulb type within a given model year.
In the 2002 model year, the front and rear turn signals both use the 5008, making that year the only one in the specifications where both positions share the same bulb type.
In the 2003 model year, both the front and rear turn signals use the 232, again representing a year where both positions share a single bulb type, though a different one from 2002.
The SV8.5 base of the 232 festoon bulb and the BA15s bayonet base of the 5008 are physically incompatible socket types, so the two bulbs are not interchangeable regardless of voltage or wattage considerations.
The rear turn signal position spans model years 1999-2005 in the specifications, while the front turn signal position spans 1999-2003, indicating the two sub-parts do not cover identical year ranges.