The best replacement for trike is motorcycle.

The best alternatives to trike are rated as following:
★★★★★  motorcycle
★★★  sidecar
★★★  spyder
★★  recumbent
★★  trikke
★★  can am
★  ultralight
★  taildragger
★  balance bike
★  powered parachute
★  trike
★  tricycle
★  reverse trike
★  recumbent bike
★  little miss twist trike
★  radio flyer 4 in 1 trike
★  goldwing trike
  can am spyder
  harley trike
  big wheel
  outrigger kit for motorcycle
  little tikes
  roadsmith
  eurotrike
  tail dragger

Your alternative for trike is not listed? Suggest!
Speaking about trike, one probably shouldn't forget about 2 wheels in front.

Other search terms related to trike and their ratings are:
★★★★★ 2 wheels in front
You have in mind a companion for trike and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of trike in all years. Click on graph for more.
trike
motorcycle
sidecar