S3tr prototype provides fold-up answer to the Segway


November 20, 2013

S3tr: lean machine

S3tr: lean machine

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At first glance, you might think the S3tr (which is apparently pronounced Streeter) is a knockdown answer to the Segway PT. Like the PT, the S3tr is a compact one-person vehicle driven by a standing rider who balances on a wheeled base and steers with the aid of an upright column. The S3tr has three wheels to the PT's two, but its main advantage is that it folds up, in theory making it more easy to take aboard public transport, or stowing under a desk at work.

The other main difference to the Segway PT, which you might see as either an advantage or disadvantage, is that motion is controlled by a thumb-controller rather than by leaning forwards or back. Steering, though, can be controlled by leaning, or by turning the control column when the vehicle is in so-called fixed mode.

The big front wheel contains the hub motor which gets the S3tr moving while the smaller rear wheels handle steering. This configuration brings about one performance compromise: though the S3tr's turning circle appears to be impressively small, it can't hope to match the PT's ability to turn on the spot.

At the moment, it seems that the S3tr is at the prototype stage. The current model uses a standard electric bicycle kit from Golden Motor which grants a range of 15 km (9.3 miles) from one charge, though it sounds as though an optional upgrade from a sealed lead acid battery to a lithium iron phosphate battery will double this. Its makers are hoping to have a product-ready design finalized within 8 months. We've asked if they have a target price in mind for the S3tr, and will let you know if we find out.

Here's a list of the specs we've seen:

  • Length: 105 cm (41 in)
  • Height: 135 cm (53 in) (60 cm/24 in without control column)
  • Width: 65 cm (26 in)
  • Folded dimensons LxHxW: 72 x 60 x 30 cm (28 x 24 x 12 in)
  • Front wheel: 508 mm (20 in)
  • Aft wheels: 200 mm (8 in)
  • Weight: 38.8 kg (86 lb) (without battery: 26.5 kg/58 lb)
  • Drive: electric motor (by Golden Motor)
  • Model: SmartPie
  • Power: 200 – 400 W
  • Battery: 48 V, 9 Ah
  • Features: integral controller, reverse, cruise control, regenerative braking.
  • Battery type:: SLA
  • Battery weight: 12.3 kg (27 lb)
  • Max. range: 15 km (9.3 miles)
  • Max. speed: 28 km/h (17 mph) (varies with controller setup and voltage)
  • You can see the S3tr in action in the video below.

    Update Nov. 21 2013: S3tr's Vladimir Bosnjak tells Gizmag that the prototype cost US$1,300 to develop, and the target price for the first production S3trs is between $2,000 and $2,500.

    Source: S3tr

About the Author
James Holloway James lives in East London where he punctuates endless tea drinking with freelance writing and meteorological angst. Unlocking Every Extend Extra Extreme’s “Master of Extreme” achievement was the fourth proudest moment of his life. All articles by James Holloway

It would have been helpful to see an illustration of what you say is the product's main advantage: folding up!


This is an electric trike scooter, not a self balancing vehicle.

It is an answer to the Segway in the same way that a motorcycle is an "answer" to a car.

Marcus Dyson

Nice design and lots of appeal here but it's very heavy - 26kg without battery. There must be some weight savings to be made here. Front wheel looks unnecessarily chunky for a start...

Richard Guy

A cross between a standard Trikke and a GoPet. But the electric Trikke does the same thing. And something in Europe has already had its debut on Gizmag (can't find the link) that is similar as well. Nothing new here but the joystick.

Bruce H. Anderson

Hey, they just reinvented the wheel! Poorly. Segway - 26 miles, not 9.3. Segway - designed from the start to interact with people. Take this on an elevator, NOT. Special non marking silicone based tires? No. The Segway costs a lot more. And is worth every penny. Oh yeah and is more than 10 years old and reliable. Not a pie in the sky prototype. And as mentioned by others, where is its primary feature? Folding. Do you want to carry it from the door of your building into the elevator and up to your desk? Sorry.

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