Standard seatposts lengths have changed over the years. Thirty years ago TCO seatposts were considered long at a little over 300mm. Then 350mm took over the market about 15 years ago. Today frames are smaller, and seat posts are longer so 400mm seat posts are common on bikes. It will be difficult finding anything longer than 400mm.

Folding bikes need longer seatposts. For twenty years they have used 500mm seatposts. Recently some have made the jump to 550mm and even 600mm. The longer seatposts accommodate taller riders, however they create a long lever from the frame. this lever can crack, or break the frame. We have decided to use tall seat tubes and 500mm seat posts to minimize the risk to the frame and allow for taller riders.