Engineering:Tikit
The tikit is a 16-inch wheel folding bicycle with an unusually fast folding mechanism that can be folded/unfolded in less than five seconds. The tikit was manufactured in the United States by Bike Friday from 2007 to 2016
Specifications
The tikit was available in three sizes: small, medium, and large. The effective top tube for the three sizes is 50 cm (19.69 in) (small), 55 cm (21.65 in) (medium), and 60 cm (23.62 in) (large). The size-Large tikit was built with a slightly thicker tubing to support larger riders. The weight for the small and medium sizes is about 24 pounds (10.9 kg). The large size is about 25 pounds (11.3 kg). When folded, the size-Small tikit fits into a 15×24×35-inch (38×61×89 cm) space.
The stock tikit came with an 8-speed SRAM rear cassette gear, in black or black/blue. Bike Friday also provided build-to-order versions, including 9-, 24-, and fixed 1-speed in a variety of colors.
Custom options were also available.[1]
Folding
The tikit folded in a unique manner.[2] A hard slap on the seatpost pushes it forward and disengages a pin held by spring steel connecting the seat mast to the rear of the bike. This enables the rear half of the tikit to rotate vertically under the bike. The seat post and handlebar stem then each fold down at slight angles to body.
A hole in an arm attached to the bottom bracket shell snaps onto a pin attached to the drive side of the lower seat tube (part of the main frame), locking the rear end in place. A pin attached to the side of the seatmast snaps into a hole in a piece attached to the non-drive side of the mainframe, locking it in place. Finally, a cap on the end of a screw attached to the stem slides into a slot on the drive side of the mainframe, securing it. This allows the bike to be picked up as one piece without unfolding and also allows the bike to wheel around by the front wheel, unlike the other Bike Fridays.
Unlike the Brompton or Birdy, this fold is not particularly compact; in fact, it is larger than many 20-and-16-inch (51 and 41 cm) wheel folding bicycles (such as those from Dahon). However, the tikit's claim to fame is the speed of the fold in its "Hyperfold" model. Here, the action of rotating the rear of the bike slackens an internal cable which enables the handlebar stem to be folded. As a result, no quick release clamps, latches, or locks are involved in the fold. This feature, unique among folding bicycles, enables the tikit to fold easily in under five seconds.
Model history
The tikit was introduced in 2007.[3] Early versions of the tikit employed a pair of brake cables in the hyperfold mechanism. This mechanism permitted excessive flex in the handlebar stem when ridden.
In 2008 a new version of the tikit replaced the pair of brake cables with a single, and much thicker, cable, plus other improvements to the handlebar stem and to the rear seat pin assembly. The resulting bike is much stiffer. Bike Friday provides an upgrade path for 2007 tikits which provides some of the 2008 features, notably the new cable assembly.
In 2008 a second version of the tikit was introduced known as the "Model T", which sports a Brompton-style "twiddly knob" on the handlebar stem rather than the cable mechanism. This extends the folding time to about ten seconds. The "Model T" is $250 cheaper than the "Hyperfold" version.
In 2009, Bike Friday announced a safety recall for the Tikit. The "aardvark"—the portion of the seatmast which folds down on its hinge—had developed a stress crack in many instances due to weight from the rider. Bike Friday sent out a special brace which completed a triangle in the aardvark and strengthened it, and also replacement aardvarks in some cases. In late 2009 Bike Friday introduced a new, stronger one-piece aardvark with the bike's handle integrated into a curved bar, replacing the brace.
In 2010, Bike Friday announced a second safety recall[4] for the Tikit, this one having to do with the stem. Geometric considerations force a small wheel bicycle to use a long stem, which is under considerable torque. Dahon Folding Bicycles also had a handlebar recall[5] in 2008.
The tikit was discontinued in 2016.[6][better source needed]
References
- ↑ "commuter & tikits". https://www.bikefriday.com/bicycles/commuter_and_itikitsi. Retrieved 15 August 2014.
- ↑ Epperson, Bruce D. (2018). The Moulton Bicycle: A History of the Innovative Compact Design. McFarland. p. 147. ISBN 978-1-4766-3240-7. https://books.google.com/books?id=fF5dDwAAQBAJ&pg=PT153.
- ↑ Glucklich, Elon (February 22, 2015). "Bike Friday gears up". https://www.registerguard.com/article/20150222/BUSINESS/302229955.
- ↑ second safety recall
- ↑ handlebar recall
- ↑ "Bike Friday discontinues the tikit". September 26, 2016. https://jnyyz.wordpress.com/2016/09/26/bike-friday-discontinues-the-tikit/.
External links
- Official Product Page
- Video Demo
- Review from The Folding Society
- Mechanical Engineering Article
- Tikit Review
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