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Electric Eco-Tad SX

  • $ 2,052.00

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  • Economical Tadpole Trike
  • 26 mph Top Speed / 10-44 Mile Range*
  • Comfort High Seat for Easy Mounting
$250 flat-rate to Contiguous USA Only
What is this?

How to Measure Your X-Seam

At we like to use the X-Seam Measurement to fit riders on recumbent trikes, and inseam to fit riders on upright trikes (like the sun traditional).

We use this measurement to adjust your trike to fit you out-of-the-box, but it's simple to adjust your trike later to suit your preferences. This is just a rough measurement to make things easier for you.

You can see how to take the measurement in our video here.


Or you can read about how to measure it in-depth here:

To measure your X-seam, you'll need a tape measure, a sturdy board (like a piece of plywood or an ironing board), and an assistant to help you. If you currently ride a recumbent bike, you can use that to take the measurement instead of the board.


Start by placing the board against a wall at 60*. You can use a protractor (or print this one out) to measure the angle, or just measure the length of your board, divide that length by 2 and place the end of the board that distance from the wall. Example: a 36" long board will be placed 18" away from the wall to get a 60* angle.


Now, measure the length from the end of the board to the end of your feet. This is your X-Seam.


If you're having trouble with the measurement or want to size your bike a different way, feel free to choose "I'm not sure" from the drop-down menu and we can discuss your needs after you place your order.




The Eco-Tad SX is the most affordable SUN tadpole trike and it's full of features. It has a fully adjustable mesh-back saddle with a padded bottom that keeps you cool and comfortable. There are spare bottle mounts on the handlebar and seat frame.

Setting this electric trike apart from others is its under seat steering with high horizontal handlebars and bottom bracket positioned slightly below the seat for more casual riding. This e-trike utilizes the compact yet powerful 1000w performance electric drive system paired with a 48 volt Li-ion battery pack for 26 mph top speeds and plenty of torque.

Model Weight Range Mount Style Cost
48v 9ah 5.8lbs 10-22 Battery bag with velcro straps Base Cost
48v 10ah 9.7lbs 12-26 Sliding plate with lock +$286
48v 20ah 14lbs  20-44 Battery bag with velcro straps +$366


Videos, written instructions and links related to the electrical system and the conversion process that was performed on this tricycle. Specific tasks and additional parts needed to convert this trike in the best possible way.

Conversion Points:




          • Most affordable tadpole
          • Under seat steering
          • Horizontal handlebars
          • Mesh padded seat
          • Simple 1x7 gearing
          • 4 x water bottle mounts

            Tricycle Specifications:

            • 20" x 1.5" Tires
            • Wheel Base: 37.5" (95cm)
            • Overall Length: 70.5"-78.75" (179-199cm)
            • Width: 31" (78.7cm)
            • Seat Height: 17"-18" (42-45cm)
            • Weight: 46lbs
            • Weight Limit: 300lbs
            • X-Seam: 31"-53" (31-79cm)


            • 80" x 40" x 44" x 190lbs


            • 1000w peak power
            • 26 mph top speed
            • 12-26 mile range
            • 48v10ah Li-ion Battery
            • USA hand-built wheel
            • 5-level top speed control


              Watts (Nominal/Peak): 500-1000w
              Top Speed: Approx. 26mph
              Range: 10-26 Miles
              Charge Time: 3hrs (0-100%)
              Weight: 21lbs (9.5kgs)


              Brand: Electric Bike Technologies
              Type: Internally Geared (brush less)
              Power: 500w nominal / >1000 @48v
              Max Torque: 84N-m @48v
              Max RPM: 320 @48v
              Cable: 8" axle exit, 3-phase / 5 hall effect
              Connector: Round 8-pin 13/32" (10.4mm)
              Weight: 9.4lbs (4.26kg)


              Nominal Voltage: 48v
              Nominal Capacity: (depends on choice - 9 - 20ah)
              Battery Energy: (depends on choice - 490 - 1092wh)
              Dimensions: (depends on choice)
              Total Weight: <= (depends on choice)
              Cell Assembly: 18650-3.6v-13S
              Life Cycles: >=80% Dod = 500 cycles
              Max. Continuous Discharge: 22.5A
              BMS Protection Current: 30A
              Discharge Cut-Off Voltage: 37.5v
              Max. Charge Voltage: 54.6v
              Inner Resistance: < 50mΩ
              Charge Time: <= 3.3 hours
              Operation Temperature Range: Charge: 0’C---45’C / Discharge: -20’C---60’C
              Storage Temperature: 0’C---40’C (Extended Storage: 15’C-25’C;)
              Battery Box Material: (depends on choice - aluminum or vinyl w/ canvas bag)
              Assembled Pack Certificates: UL; UN38.3; MSDS; RoHS; SGS
              Manufacturer: Electric Bike Technologies

              UN 38.3 Certified E-Bike Battery



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