Bikes and Trikes

Trikes or bikes, bikes or trikes? So which is best?

Well we have our favourite, but the honest answer is that they both have their benefits and downsides, so lets take a look at how they compare as cargo transport.

Trikes are often what people first imagine when you talk of cargo bikes; probably from seeing the ice cream vending trike at the local fete, or the hot dog stand in the town square. So what are the merits of this interesting vehicle?
First of all trikes can be Tadpole or Delta configured. A Tadpole trike has two wheels at the front and the Delta has the two wheels at the back.

A Delta trike is perhaps more traditional, Pashley make adult trikes to this design and tuk-tuks and rickshaws are made with the same wheel configuration. The front of these vehicles can be made of standard bicycle parts but the rear axle is a bit more specialised and may have a differential or a budget model might just be one-wheel drive.

A Tadpole trike has two steering wheels at the front. These might use clever Ackerman steering or more likely with just have a central pivot on which swings a rigid front axle. The Ackerman steering is nice and is well suited to fast recumbent, but cargo bikes usually have simple beam steering and as a consequence steering response is affected by weight of cargo in the box and how it is distributed.

Simple, Strong Cargo Trike

Some hi-tech tadpole trikes allow tilting of the riding frame for faster corners and we should look into these in more detail another time, but the majority of trikes with two front wheels have very simple beam steering which is what we will consider for this essay. Nonetheless, even a simple “beam steered” trike can benefit from an angled pivot which allows the rear of the frame to tilt into a corner. This helps make corning feel more natural and is worthwhile feature to consider if you are looking to purchase a trike.

All bicycles and in fact most wheel driven vehicles benefit from self centring steering which helps the vehicle travel straight when there is no steering input. In cars this is provided by the caster angle, in bikes by the mechanical trail and it is beneficial feature which provides a more relaxed ride. For this reason the steering pivot on a trike should be mounted ahead of the front wheel centreline so that the driven part of the trike (the back-end) is effectively pulling the front wheels to help them go straight. However once again this ability to track in a straight line is affected by the distribution of cargo in the box and the road camber.

Handling.
A fundamental issue with non-tilting trikes is their dynamic handling. First of all riding on any kind of road camber will mean the rider is not sitting centrally on the saddle. All riders will naturally sit upright on a saddle even when the trike is tipped and this can be uncomfortable. The trike will constantly pull towards the kerb side too, and this can be wearing after a while. There is also a potential to tip a trike. Turning too sharply or cornering too fast can topple a trike. Most transport vehicles will skid before they topple but this is not true of trikes (or sidecars or quad bikes for that matter), so riders must progress with this in mind. With tadpole trikes there is a cornering technique which involves the rider crossing their hands over so that they can lean into a bend to help reduce the tipping risk, this is a good idea and will come with a little practice. But it is unfortunate that with a simple trike with two wheels at the front the more you turn, the narrower the wheel track gets which is the opposite of what would be best.

Illustration of reduced wheel track turning a corner

What of two wheelers?

Well the two-wheeled cargo bike is almost the reciprocal of the trike. It is more sleek, faster, with better handling and we consider it safer because of this. It is not a perfect vehicle and of course when stationary the rider will have to balance the weight of the cargo whereas the trike is statically stable. Two wheeled bikes have to be lifted onto a sturdy stand to park them whereas trikes will just park up and apply a hand-brake. But the humble box bike is a very good compromise between capability and ridability. It holds cargo low down between the wheels which is fundamental to stability and handling. Standard bikes parts are used front and rear………

Capable Box BIke

Conclusion.
Our opinion is that for real work and transport of cargo the 2 wheeled bicycle outdoes the trike. This is because of sweeter handling characteristics, narrower overall width and a more intuitive riding style. The trike has a place, ideal for vending, and more stable when parked, but as a vehicle it is limited due to road cambers and tipping tendencies. The trike weight capacities are larger, often seen transporting 4 or 5 children they are very strong.

We also consider 2 wheel cargo bikes to be well suited to electric assist. They can run quite fast and, provided adequate brakes are specified, operate perfectly safely at speed. Trikes may feel like they need to be electrified because of their weight, but performance needs to be matched to their road holding capabilities.

 

George, he rode a tricycle,
He rode it to the shop,
But when he turned a corner,
He was forced to make a stop.

The steering was not optimum,
But george he had a plan,
He’d fit it with some better links,
From Rudolph Ackerman*.

*Actually Rudolph was the Patent agent, credit to the innovation should be given to Georg Lankensperger from Munich or Eramus Darwin (not that Darwin though).

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