if you wanted maximum braking, where would you sit?

if you could position your center of gravity anywhere, to ensure
maximum braking power, where would it be?

obviously over the front wheel is no good, you would flip.

there is a point, leaning either ahead of the front wheel, or
behind the back wheel, that the opposite wheel is off the ground.

clearly those are 2 limits, the answer must lie between them.

if there were very little friction, it would hardly matter.

assume a level road, brakes that can cause a skid no matter what.

ok, so where do you sit?

state assumptions, like coefficient of friction between tire and road,
weight of bike and rider.

show your work.

now for extra credit, make it a function of road slope.

wle.

On 7 Jan 2004 16:33:02 -0800, (wle) wrote:
if you could position your center of gravity anywhere, to ensure
maximum braking power, where would it be?

On a flat piece of rubber in direct contact with the pavement.

wle.
--
Rick Onanian

(wle) wrote in
om:
there is a point, leaning either ahead of the front wheel, or
behind the back wheel, that the opposite wheel is off the ground.

Unless you're climbing a steep hill, you're going to have a real hard time
lifting the front wheel. If the hill is that steep, stopping shouldn't be a
problem.

On Thu, 08 Jan 2004 01:47:26 +0000, Ken wrote:

(wle) wrote in
. com:
there is a point, leaning either ahead of the front wheel, or
behind the back wheel, that the opposite wheel is off the ground.

Unless you're climbing a steep hill, you're going to have a real hard time
lifting the front wheel. If the hill is that steep, stopping shouldn't be a
problem.

Underground. ;-)

wle wrote:

if you could position your center of gravity anywhere, to ensure
maximum braking power, where would it be?

obviously over the front wheel is no good, you would flip.

there is a point, leaning either ahead of the front wheel, or
behind the back wheel, that the opposite wheel is off the ground.

clearly those are 2 limits, the answer must lie between them.

if there were very little friction, it would hardly matter.

assume a level road, brakes that can cause a skid no matter what.

ok, so where do you sit?

state assumptions, like coefficient of friction between tire and road,
weight of bike and rider.

I would sit near or below the level of the front axle to reduce or
elminate the tendency for the rear wheel to lift off of the ground, and
I would also be near the rear wheel for more favorable weight
distribution for braking. This describes a recumbent lowracer. Braking
can be improved by adding a second wheel in front (tadpole trike) as
weight transfers forward to two contact patches during braking, and
locking one or both front wheels under braking will not lead to a loss
of balance.

Tom Sherman - Quad Cities

On Wed, 07 Jan 2004 19:54:47 -0600, Tom Sherman
wrote:
I would sit near or below the level of the front axle to reduce or
elminate the tendency for the rear wheel to lift off of the ground, and
I would also be near the rear wheel for more favorable weight
distribution for braking. This describes a recumbent lowracer. Braking
can be improved by adding a second wheel in front (tadpole trike) as
weight transfers forward to two contact patches during braking, and
locking one or both front wheels under braking will not lead to a loss
of balance.

I imagine that all of those conditions would result in fishtailing
under very hard braking. Is that the case?

Tom Sherman - Quad Cities
--
Rick "Sounds like fun!" Onanian

Rick Onanian wrote:

On Wed, 07 Jan 2004 19:54:47 -0600, Tom Sherman
wrote:

I would sit near or below the level of the front axle to reduce or
elminate the tendency for the rear wheel to lift off of the ground, and
I would also be near the rear wheel for more favorable weight
distribution for braking. This describes a recumbent lowracer. Braking
can be improved by adding a second wheel in front (tadpole trike) as
weight transfers forward to two contact patches during braking, and
locking one or both front wheels under braking will not lead to a loss
of balance.


I imagine that all of those conditions would result in fishtailing
under very hard braking. Is that the case?

Fishtailing only happens on the recumbent lowracer [1] when the rear
wheel is locked up, and this takes considerably more braking force than
it does to lock up the rear wheel on an upright.

My trike [2] has two front brakes (Avid mechanical disc on each wheel -
one lever for each brake) and no rear brake. Stopping quickly takes as
much skill as stopping an automobile without ABS and the brakes biased
towards the front.

Subjectively, the stopping power does not feel as great as it is, since
the rider is naturally braced by his/her legs being on the pedals,
unlike an upright bike where bracing is done with the (much weaker) arms.

[1] This does not apply to all recumbent bikes. Some are poorly designed
with a high seat and too much weight on the front wheel, and may have
braking performance that is worse than an upright bicycle.
[2] http://home.mindspring.com/~kb7mxu/i...ragonFlyer.jpg This
is the same model as my trike.

Tom Sherman - Quad Cities

On Thu, 08 Jan 2004 19:34:05 -0600, Tom Sherman
wrote:
My trike [2] has two front brakes (Avid mechanical disc on each wheel -
one lever for each brake) and no rear brake. Stopping quickly takes as

Wow! Cool...fail-safe steering.

Tom Sherman - Quad Cities
--
Rick Onanian

On Fri, 09 Jan 2004 10:52:59 -0500, Rick Onanian
wrote:
wrote:
My trike [2] has two front brakes (Avid mechanical disc on each wheel -
one lever for each brake) and no rear brake. Stopping quickly takes as

Wow! Cool...fail-safe steering.

Nevermind; I just looked at the picture, and it was the ONLY
steering.

Okay...Wow! Cool...integrated steering.

Okay, on a second look, I think I see spindles and control arms. Do
you steer with the brakes, with the front wheels, or with the rear
wheel? What control do you operate to steer? Do you steer with the
handlebars, which then aim the front wheels through control arms?
--
Rick Onanian

Rick Onanian wrote:

On Wed, 07 Jan 2004 19:54:47 -0600, Tom Sherman
wrote:
I would sit near or below the level of the front axle to reduce or
elminate the tendency for the rear wheel to lift off of the ground, and
I would also be near the rear wheel for more favorable weight
distribution for braking. This describes a recumbent lowracer. Braking
can be improved by adding a second wheel in front (tadpole trike) as
weight transfers forward to two contact patches during braking, and
locking one or both front wheels under braking will not lead to a loss
of balance.

I imagine that all of those conditions would result in fishtailing
under very hard braking. Is that the case?


Rick "Sounds like fun!" Onanian

No, it isn't the case on any of my trikes. Yes, it is fun.

--
Ted Bennett
Portland OR