Trail Cruiser
Well-Known Member
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Bicycle / stroller / grocery cart / delivery cart, 2018 Eurobike Gold award winner.
- Thread starter Trail Cruiser
- Start date
Nova Haibike
Well-Known Member
Amphibian Series? I was expecting it to also go in the water. 
Cool product though, and yes, it needs a motor option.
Cool product though, and yes, it needs a motor option.
Trail Cruiser
Well-Known Member
Right off the bat, I can see there's a problem with torsional rigidity that can cause speed wobble. The middle articulating frame (enclosed by violet color) is not very secure. Or if it needs be very rigid, it has to be really heavily built since the straight middle frame (hefty parallel double I-beams with king pins on both ends) doesn't have vertical extensions for mechanical advantage for rigidity.
If I am the engineer of this bike I would focus more on increased rigidity and light weight construction. From a 79 pound bike, I would shorten the whole length (red lines and red arrows above) and put a light weight single piece hollow middle frame with vertical extensions on both ends (secured by quick release pinch locks) to increase strength and torsional rigidity without sacrificing the overall weight (violet superimposition).
see the parallel double I-beam at 2:53 of the video below.
If I am the engineer of this bike I would focus more on increased rigidity and light weight construction. From a 79 pound bike, I would shorten the whole length (red lines and red arrows above) and put a light weight single piece hollow middle frame with vertical extensions on both ends (secured by quick release pinch locks) to increase strength and torsional rigidity without sacrificing the overall weight (violet superimposition).
see the parallel double I-beam at 2:53 of the video below.
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Trail Cruiser
Well-Known Member
Those articulating king pins on both ends of the middle frame can be major source of tolerance issues. Even one piece non articulating frames, like many step thru frames have speed wobble issues. And that even includes reputable manufacturers like Bulls.
https://electricbikereview.com/foru...help-on-bulls-lacuba-evo-e8-wave-frame.14247/
" A VERY LARGE ORANGE LABEL on the bike, stating something like:
This is a step-through bike. As per its inherent design, an extremely dangerous situation may develop leading to severe injuries or even death. Under ANY circumstances do not to exceed the speed limit of 20 mph (32 km/h) or extreme wobble of the front wheel, leading to the loss of control of the bicycle WILL occur.
KEEP both hands on the handlebars at ALL TIMES. "
https://electricbikereview.com/foru...help-on-bulls-lacuba-evo-e8-wave-frame.14247/
" A VERY LARGE ORANGE LABEL on the bike, stating something like:
This is a step-through bike. As per its inherent design, an extremely dangerous situation may develop leading to severe injuries or even death. Under ANY circumstances do not to exceed the speed limit of 20 mph (32 km/h) or extreme wobble of the front wheel, leading to the loss of control of the bicycle WILL occur.
KEEP both hands on the handlebars at ALL TIMES. "
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