The best replacement for training wheels is balance bike.

The best alternatives to training wheels are rated as following:
★★★★★  balance bike
★  strider bike
★  no training wheels
  tricycle
  balance bikes

Your alternative for training wheels is not listed? Suggest!
Speaking about training wheels, one probably shouldn't forget about bike.

Other search terms related to training wheels and their ratings are:
★★★★★ bike
★ bicycle
★ tequila
You have in mind a companion for training wheels and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of training wheels in all years. Click on graph for more.
training wheels
balance bike
strider bike