The Triumph Bonneville T100 uses 5008 and 232 bulb sizes for both front and rear turn signal applications. The replacement chart covers 2002 through 2018 production 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 5008 is a single-filament bulb with a BA15s bayonet base, rated at 12V, and is classified as a lower wattage variant of the 1156. The 232 is a festoon-type bulb with an SV8.5 base, rated at 12V and 3W. These two bulb types represent entirely different base designs and are not interchangeable with one another.
The BA15s bayonet base of the 5008 uses a single contact point at the base, which is a standard single-filament configuration. This distinguishes it from dual-filament bayonet bulbs, which share a similar physical form but carry a second contact for a separate circuit function such as braking or running light.
The 232 festoon bulb seats at both ends of its cylindrical body rather than at a base pin or bayonet cap. The SV8.5 designation refers to the contact cap width, which determines socket compatibility. A festoon bulb of a different cap width would not seat correctly in a socket designed for the SV8.5 standard.
On the Triumph Bonneville T100, the front turn signal uses the 5008 for the majority of model years across the 2002-2018 range, with the 232 appearing in 2004, 2005, 2015, and 2017. This means the front housing design and socket type varied across production years.
The rear turn signal specification shows a similarly mixed pattern, with the 232 appearing in 2002, 2004, 2006, 2010-2011, 2014, and 2017, while the 5008 covers the remaining years. The front and rear positions do not always share the same bulb type within a given model year.
In 2017, both the front and rear turn signals use the 232, making it one of the few years where the same bulb type is specified for both positions. In 2018, both positions use the 5008, representing another year of front-to-rear consistency.
In several years, the front and rear turn signals require different bulb types. The 2014 model year, for example, specifies the 5008 for the front and the 232 for the rear, while 2015 reverses this, with the 232 at the front and the 5008 at the rear. Treating these positions as interchangeable in those years would result in an incorrect fitment.
Both the 5008 and 232 are ANSI-standardized bulbs recognized in the US and Canadian markets. ANSI standardization means the electrical and physical specifications are defined by a published standard, and bulbs from different manufacturers carrying the same designation are expected to conform to the same ratings.