ICB 4-wheeler

08-03-2016 14:47:02
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Intercitybike bouwt prototype 4 wieler

The fastest and lightest velomobile will always be a tricycle but Miles Kingsbury demonstrated by its Quattro velomobile that the 4-wheeler concept is definitely worthwhile to investigate.

Kingcycle Quattro 4x16"

We have visions of an accessible luggage compartment with room for a child, dog, luxury camping gear or luggage packed in a carton or a crate. In addition, a 4-wheeler at the same width has better cornering stability and better handling in the event of a tyre problem at the rear, our colleagues from Velomobiel.nl have been writing extensively. on this subject.

To test possibilities and ideas an ICB 4-wheeler prototype is now being built by Daniel Fenn. All designs are compromises but if our designer allows compromises on speed and weight we might as well grab those and explore further. Of course we keep in mind that we are skating on thin ice, too much compromise and we will loose it all and better tow a trailer.

We propose:
-4 identical wheels, these are a one bolt removable and interchangeable so you can use a spare wheel with in case of a flat tire
-20 "Wheels with rim diameter 451 mm have 28 the same circumference as 406 wheels with a 50mm tyre. So you can choose driving with narrow or wide tires while keeping a perfect fit into the wheel arch.

20" 406-50mm

20" 451-28mm

-all four wheels get a drum brake, we will test foot operation by a free wheel and lever on one crank
-the bike will have a left-chain along the frame, the chain will have maximum distance from your leg and torsional forces on the frame is reduced.

inside front wheel box with cut out for the Rohloff shaft

The chain is taken to the left side of the bike by a hub Rohloff 14v hub, after which it directly drives the left rear wheel with 10 speed cassette en short cage dérailleur. The drive losses of the hub are limited if you choose the ratio in a way that you normally drive in the direct driven 11 th gear. The bike will now have 140 gears, not that you need all that but you may like the 1000%++ range, especially if you meet some hills. And this hub gear enables you to shift gear at standstill. By driving 1 wheel there will be no shaft assembly which limits the luggage compartment. The suspension is designed in a way the wheels do not move sideways, which leaves again more luggage space because the wheel boxes can be very narrow. In order to get sufficient rear wheel pressure for traction the wheelbase will be shorter compared to the current three-wheelers, which is good for manoeuvrability.
-the 4th wheel may be driven by E-motor over a small chain and freehweel. The motor will not be integrated into the design makes it easy to add or remove.
-the rear is formed in a way the bike can stand upright on its tail.
The larger diameter wheel/tyre gives more ground clearance compared to the regular DF. The larger wheels needs deeper wheel wells not too enlarge the turning circle. It makes the bike slightly wider but furthermore we will preserve "DF DNA" as much as possible, stiff, light and fast, dense foot holes, ventilation via frame tube.

2 DF-XL Bodies will be cut into pieces

The prototype will be made out of two single DF-XL bodies. This prototype is designed to be as light as a possible production model. We need half a year for building and testing, and if we still like this bike we will have to make molds and other tools to produce it. So if you are interested you need some patience, we will show up with the prototype as soon as possible. If you are able to understand German you may follow the project also on the German velomobilforum..