tridem

Blend of tri- +‎ tandem.

• IPA^(key): /ˈtɹaɪdəm/

tridem (plural tridems)

1. An arrangement of three objects arranged one behind the other.
   • 1990, Truck Weight Limits: Issues and Options‎, Washington, D.C.: Transportation Research Board, page 187:

     Four-axle trucks with a conventional 9-ft overall spacing for the tridem axle would have a maximum GVW of 64,000 lb (limited by 44,000 lb on the tridem).

   • 2015 May, “Appendix A: State Truck Size and Weight Laws”, in Anthony R. Foxx, editor, Compilation of Existing State Truck Size and Weight Limit Laws, Washington, D.C.: Federal Highway Administration, retrieved June 25, 2019:

     The State bridge formula allows 42,000 lbs. on a tridem axle on non-Interstate highways.

• triple

• tridem axle

• mitred