Chevrolet Biscayne Radio Display Bulb Size

Additional Notes

• The radio display bulb specifications for the Chevrolet Biscayne span the 1958-1972 model years, covering three distinct bulb types: the 1816, 1893, and 1891.
• The 1893 and 1891 are both T5 miniature wedge bulbs rated at 12V and 2W under the ANSI standard for the US and Canada, making them electrically identical despite carrying different part numbers.
• Although the 1893 and 1891 share the same voltage, wattage, and T5 envelope designation, they are listed as separate part numbers, which indicates a physical or base difference that affects direct interchangeability.
• The 1891 is specified for the Chevrolet Biscayne across the 1958-1963 model years, while the 1893 takes over for the 1964-1971 range, representing a shift in radio display bulb fitment at the 1964 model year.
• The 1816 is a T3.25 miniature wedge bulb rated at 12V and 4W under the ANSI standard, making it the highest-wattage bulb in this specification set and the only one with a T3.25 envelope.
• The 1816 is specified exclusively for the 1972 model year, the final year of the Biscayne, and its higher 4W rating distinguishes it from the 2W bulbs used in all prior model years.
• The T3.25 envelope of the 1816 is physically smaller than the T5 envelope of the 1891 and 1893, meaning these bulb types are not interchangeable despite all three using a wedge base format.
• All three bulb types carry ANSI designations valid for both the US and Canadian markets, indicating standardized availability across North America.