ON YA CYCLES - Steering geometry optimizer
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GNARLY MATH: (Above) The
tie rods and steering arms of
Griffith’s cargo trike extend
standard Ackerman steering
into three dimensions. This lets
the trike’s two front wheels
lean as well as turn at different
angles as they follow their own
arcs, minimizing side-slippage
and other sources of friction.
(Left) Graph generated by the
7,000-line computer program
that Griffith wrote to find the
optimal geometry for his tilt-steering system.
and angles, and found the optimal combination,
assuming a typical range of steering radii.
The result, converted from MATLAB to metal, is
a tricycle that feels uncannily like a bicycle, with a
one-minute learning curve that teaches riders to
ignore the sight of a big cargo basket swaying side-to-side in front of them and to just ride normally.
Such a system would knit communities together,
rather than drive them apart. The able-bodied
could transport cargo and other people around,
and everyone could live, breathe, and congregate
in safety, moving around without a wall of armor
surrounding them.
Many people seem to be yearning for a new
kind of transportation system, and whatever the
future holds, the freight-carrying bicycle will be an
important part of it. It’s cheaper, more fun, healthier, simpler, more elegant, and more conducive to
community than the alternatives. And designing,
making, and pedaling new variations of cargo bikes
around our cities and towns should keep us busy
for many years to come.
Photography by Saul Griffith
Cargobiketopia Rising
As a transit planner and bike activist, I’m thrilled
about what Muir and Griffith are doing, as well as
many others who are designing not just new bikes
but also local bike-sharing systems, maintenance
collectives, and plans for reclaiming bike-friendly
roadway and path infrastructure (often located
along old rail rights-of-way, canals, or rivers).
Building level, regional bike routes has so far
been carried out piecemeal, and mostly in the
name of recreation. But bike routes could also
become an arterial network for transporting people
and cargo throughout re-localized communities.
Combine this with “intermodal” connections to
express buses and trains, and you’ve got a sustainable transportation system with quality of life as
the driving force.
Thanks to Stephen Bilenky and Erik Zo for helpful
background information.
Joshua Hart (
joshuanoahhart@gmail.com) is a Bay Area
resident with 15 years’ experience advocating for self-propelled transportation. His master’s thesis, “Driven to
Excess,” was covered by more than 100 media outlets
worldwide. He maintains a blog about transportation and
climate issues at
onthelevelblog.com.
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