On Mon, 21 Jun 2004 22:04:55 +0100, Danny Colyer wrote:

I never used to notice it, but now I often notice myself starting a turn
by countersteering. For some reason it's much more noticeable on the
Street Machine that it used to be on my ATB. Perhaps it's more
necessary on a bent than on a wedgie.

Perhaps it's more noticable because of the lack of weight on the hands &
arms?


Last week, after reading the explanation of bicycle steering in the 3rd
edition of "Bicycling Science" I did some experimenting. First on the
Speed Ross swb recumbent. I took it to a local industrial estate with a
reasonable area of concrete to play on. The bike would turn _either_
with a very gentle movement of the bars _into_ the turn or with a
positive push _out of_ the turn. A sharp push out of turn generated
a real feeling of instability as it first went in the direction of the
bars then reversed -- with the rear tyre protesting. I didn't go too far
with this, falling off onto dirty concrete is not fun. Once in the
turn the bars were turned very noticably into the turn, but had to held
with a force out of turn. Letting go of the bars instantly dropped it
into turn, and to straighten up the bars had to be pushed out of turn.
At higher speed corners on the road, I believe that the out of turn
force needed for constant cornering reduces, but haven't found a
suitable place the test.

Now on the wedgie (a Moulton AM). I really could not detect what
movements or forces were involved in getting it to turn. Possibly
because I was doing through weight shift, but I think it was because the
forces are so light and considerably less than the loads due to body
weight. However, to keep a turn going it needs into turn bar position.


Lastly a couple of motorbike experiments from some time ago. To start
the turn takes a definite push _out_ of turn -- the classic
countersteer. Push harder and the 'bike drops into the turn faster. To
straighten up push _into_ turn. However the two 'bikes behaved
differently mid-turn, one needed slight into turn bar position and the
other needed slight out of turn. Initiating a turn by weight-shifting
works, but slowly.


I am far from convinced that anyone (D G Wilson included) has yet fully
worked out all the factors involved in bicycle steering...




Mike