TerraTrikes use a sizing measurement called an X-Seam. This measurement helps us to determine which size will best fit you. Here is how we you determine your X-Seam size.

Wear shoes you would typically use for riding. Sit very tight against the bottom of the board, lean back, and stretch your legs out straight with the soles of your shoes perpendicular to the floor. Measure the distance in inches from the front of board to the bottom of your shoe. This is an important measurement so have an assistant help you get an accurate number. Use an ironing board, a piece of plywood or whatever you can find. Lean it against a wall at the recommended angle or as close to it as you can eyeball.

The boom tube is the front part of the frame that holds the bottom bracket, crankset and pedals. It attaches to the frame where the outrigger tubes meet the main tube(or where the arms of the frame meet the body). All models have adjustable booms so one size fits all per the charts below. The Tandem Pro has a detachable boom tubes of different lengths but they are not a sliding adjustable piece.

The boom tube length guidelines listed below are merely suggestions, this is by no means an exact science. For those of you who are on the fence, here are some guidelines. If you’re the serious racing type who likes to recline the seat all the way back and go fast, add an inch to your x-seam measurement. If you’re more inclined (no pun) to sit very upright and just cruise around town and be cool, you might need to subtract an inch.

Maverick Rover Traveler Rambler Sportster Gran Tourismo
38″ – 47″ 32″ – 47″ 38″ – 47″ 38″ – 47″ 37″ – 50″ 36″ – 45″


Frame Size Tandem Pro Front
Captain X-Seam
Tandem Pro Back
Stoker X-Seam
Short 37.5″ – 39.5″ 35.5″ – 42″ One Size fits both short and medium
Medium 39.5″ – 41.5″
Long 41.5″ – 43.5″ **
Frame Size Rover Tandem Front
Captain X-Seam
Rover Tandem Back
Stoker X-Seam
Short 32″ – 37″ 31″ – 43″ One Size fits both short and medium
Medium 37″ – 42″
Long 42″ – 47″ **
** There is no long option in the rear. The larger rider should captain the Tandem for optimum handling.