Hi Tom,
Does it fall over? Of course it falls over. No matter how much or
little trail there is, it will eventually fall down.
How will these studies affect bike design?
One impact: This study has provided the theoretical underpinnings for a
branch of bicycle designs based on much lower trail numbers than we've
seen in the last 20 years. Normally, bicycle trail varies from 54mm for
"fast steering criterium bikes" to 75mm for 29ers. Championed by Jan
Heine of Bicycle Quarterly and Mike Kone, owner of the Rene Herse and
Boulder Bicycle brands, these bikes have low trails, exceptionally long
fork rakes and slack head angles - with trail numbers ranging from 30mm
on 26" wheels to the low 40's on 700C wheels. They've become popular
with randonneurs, who travel long distances at moderate speeds with
handlebar bags. This kind of design violates a lot of generation-old
design rules and yet has earned a growing following.
What they will do is help keep people's minds open about possibilities
and to help us incorporate more factors in engineering designs. I'm
dubious that predictive calculation will replace tinkering as our path
to innovation. It's relatively easy and cheap to tinker, and hard to
research through calculations alone. Their model involves at least 7
dimensions which will require considerable research in order to
establish reliable design rules.
Back in the Schwinn days, we used fancy calculations to help design the
perfect tandem, only to find out that pretty close to ideal designs had
already been in the market for years. What's more likely to happen is
that we will be able to understand more of the reasons that steering
works here and not there. Then we go on to the next experiment.
Thanks,
Richard
Trail and inertial force may not be required for a bicycle to at least
somewhat self correcting. That doesn't mean that trail and gyroscopic
force don't have an important impact on steering. While that
trail-less/mass-less wheeled showed some some self-correcting
capability, it sure didn't look "rock steady". Imagine how much harder
it would have been even on the outdoor pavement than on the precision
level conditions inside the test lab.
On 4/20/2011 10:43 AM, Tom Held wrote:
Richard, but at some point the bike does fall over, right. When it loses
momentum?
I interviewed Jim Papadopolous last week but couldn't get the story in my
head. I plan to write something later this week, though.
One element that I think is missing, maybe you could fill in:
What's the practical application for this? How will it change or help bike
designs / builders? Why is this important?
Tom
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Richard Schwinn
Sent: Wednesday, April 20, 2011 10:42 AM
To: Bikies
Subject: Re: [Bikies] Science Friday - self-steering bicycles
What a terrific video! We did some experiments on creating a bike that
wouldn't self steer, and the only way we could figure out how to make
the bike automatically fall over was to lock the fork so the bike
couldn't self-correct.
On 4/20/2011 10:09 AM, Robbie Webber wrote:
On Friday's segment of NPR's Science Friday . . .
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