the burke series of titanium folding bikes are based on worldwide-patented designs by dr. mike f. yap, engineering professor, cycling enthusiast, and founder at the personal mobility solutions company ‘seattle cycles’. he is also the creative mind behind the award winning design of the airnimal folding bikes. this project presents ‘burke 20′, which  is the first full titanium folding bike made in the USA, by lynskey performance. 


the Burke 20 can be folded and packed into a suitcase in seconds, without complicated assembly or use of tools

 

 

david lynskey, the frame builder of burke 20, is a founder of the well-known litespeed bicycles company and one of the pioneers of titanium frame manufacturing. ‘the burke 20 is a high performance folding bike engineered to be light, fast, and tough. It packs into an airline compliant suitcase in seconds without special tools,” said mike yap. it is arguably the world’s most compact folder with 20-inch wheels — whereas most common folding bikes have a hinge on the frame that allows it to fold sideways to reduce its size.


david and mark lynskey, pioneers of titanium bicycle manufacture in the USA

 

 

 

the burke 20 uses a simple but novel gravity-assisted, double vertical folding design. the hinge positions and angles are precisely calculated to allow both front and rear wheels to fold vertically toward the central frame without interference. the process is naturally assisted by the weight of the bike itself, achieving a very quick and compact fold. commercial airlines impose a hefty fee for oversized baggage, and most folding bikes are not designed to fit into airline-compliant suitcases. If we look at the aspect ratio of folded bikes, we see that most are either too square or too long.

 

‘packing a folded bike into a suitcase, if at all possible, requires either tedious disassembly of bike parts, or the use of an expensive custom made case. as with many things around us (picture frames, TVs, smart phones), most suitcases have length and width aspect ratios that approximate more to the golden rectangle than the square’, mike yap continues. 


lynskey has been working with titanium for three generations

 

 

with the double vertical folding design, the burke 20 folds into a tidy rectangular package with no sharp protrusions. it packs neatly into a standard, airline-compliant suitcase in a matter of seconds. but why titanium? titanium is probably the best material for a folding bike — given how its high impact strength, corrosion resistance, and lifetime durability are ideal properties for a bike built to withstand the rigors of urban transportation and international travel.


all welding and machining work is done in chattanooga, tennessee

 

 

however, a disadvantage of this design is the predominantly vertical orientation of the axis of the frame hinge. natural forces at play during normal riding tend to put much bending stress on the main frame hinge and to unfasten the hinge; thus strong clamping means must be used to keep the hinge closed. over time, the hinge may also develop play in the joint due to the high bending forces on the pivot. another disadvantage is that folding requires effort to move the front wheel assembly sideways about the hinge, transversely through a wide angle of approximately 180 degrees. this is a rather unwieldy operation and compromises folding and unfolding time. 


argon gas is pumped onto the weld to create an oxygen-free environment


purposely built for exploring urban landscapes, but easily capable of long distance touring


titanium is ideal for folding bikes thanks to its high impact strength, corrosion resistance, and lifetime durability

 


anodized titanium logo: the colors from anodizing are not a dye or a pigment, and cannot fade


the patented design achieves amazing compactness in folding by using a minimal number of simple rotary hinges


20-inch wheels and 135 mm rear dropout spacing allow for a wide gear range, superior stability and handling 


unlike most folding bikes, the wheels and handlebar remain parallel to the frame after folding


a simple folding design, coupled with the best frame materials and state of the art components, makes it lightweight

 

 

designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

 

edited by: lea zeitoun | designboom

  • Thanks very much for publishing our project. Just want to point out that the last paragraph actually refers to most other folding bike designs (that fold sideways), not the Burke 20.

    “However, a disadvantage of this design is the predominantly vertical orientation of the axis of the frame hinge. natural forces at play during normal riding tend to put much bending stress on the main frame hinge and to unfasten the hinge; thus strong clamping means must be used to keep the hinge closed. over time, the hinge may also develop play in the joint due to the high bending forces on the pivot. another disadvantage is that folding requires effort to move the front wheel assembly sideways about the hinge, transversely through a wide angle of approximately 180 degrees. this is a rather unwieldy operation and compromises folding and unfolding time.”

    MikeYAP says:
  • Brompton still the best? I think so

    marc says:

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