Rear steer 2 wheeler

Bill Patterson <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Today I saw an amazing sight. One of the engineering design students rode a front drive/rear steer
bike. He then loaned it to a friend who wobbled a little and rode away.

Amazing happenings at the CALPOLY Bike design class demo day parade.

Zowee... but how fast did they go? IIRC, the problem with rear steer is that control forces drop
with greater speed, unlike conventional steering where they increase with speed.

Jeff

Nobody went fast. Just staying up was the miracle.
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Quoted post said:

Originally posted by Bill Patterson
Today I saw an amazing sight. One of the engineering design students rode a front drive/rear steer
bike. He then loaned it to a friend who wobbled a little and rode away.

Amazing happenings at the CALPOLY Bike design class demo day parade.
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Professor:

Can you give some details on the fwd/rear steer design?
Particularly the trail/rake?
Or will there be pics after the show?
Was the design one in which several riders were able to master the ride?
Anything else particularly unusual.

BTW: your personal FWD lowracer is reported as having suspension. That’s not apparent from the pics you posted. Is there a head shock or some other implementation? Are the feet sprung?

Bill,

Quoted message said:

Today I saw an amazing sight. One of the engineering design students rode a front drive/rear steer
bike. He then loaned it to a friend who wobbled a little and rode away.

Can you post some pictures of this bike?

Warren

"Bill Patterson" <[email hidden]> wrote in message
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Quoted message said:

Today I saw an amazing sight. One of the engineering design students rode a front drive/rear steer
bike. He then loaned it to a friend who wobbled a little and rode away.

Given that you have often said that this combination doesn't produce a ridable bike, what's unique
about this one? What trick of geometry, rake, wheelbase, etc. makes this one ridable when so many
haven't been?

It has often been discussed that an FWD/RWS bike is inherently unridable, but it has also been noted
that it is not uncommon to see accomplished track bike riders mount the bike backwards and pedal
away backwards. I have yet to hear an explanation why FWD/RWS in unridable when there are so many
contrary examples on uprights.

Inquiring minds (with little else to do) would like to know

<Chas> Can't ride so I have to ask stupid questions on ARBR

My front drive low racer has a "Lord" machine mount on a trailing link suspension system. The
elastomeric mount costs 9 dollars and gives a very nice ride.

The front fork/suspension units for the front and the rear are the same.
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Rear wheel drive geometry----

I don't have the particulars at this time. I hope to get all the data after Christmas. The bike
rider is setting in a normal upright position and is quite high.

I always told the students to try riding a track bike backward. It seems easy for some. A trackie
riding backward is in fact a rear steer front drive equivalent. He just built an upright with a
front drive and a rear steer.

IMHO a high bike will be slower to react and give the rider time to make the proper corrections. We
still don't have a good recumbent configuration.

I'll try and get a photo on my web site this afternoon.
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Quoted message said:

It has often been discussed that an FWD/RWS bike is inherently unridable, but it has also been
noted that it is not uncommon to see accomplished track bike riders mount the bike backwards and
pedal away backwards. I have yet to hear an explanation why FWD/RWS in unridable when there are so
many contrary examples on uprights.

Ahem. Err.. were you going to mention some of the contrary examples? I don't know how a rear-steer
bike would work. I guess they do, but it beats me.

Riding on a bicycle backwards is not difficult. I am a over-weight middle-aged balding office-worker
guy and I can do this easily. But a little further reflection will show that this has nothing to do
with the bicycle ITSELF going backwards. Note that the bicycle and its dynamics do not care which
way you are facing.

"GeoB" skrev ...

Quoted message said:

Riding on a bicycle backwards is not difficult. I am a over-weight middle-aged balding office-
worker guy and I can do this easily. But a little further reflection will show that this has
nothing to do with the bicycle ITSELF going backwards. Note that the bicycle and its dynamics do
not care which way you are facing.

If you are riding a fixie the bike will be going backwards.

M.

The rider doesn't turn around on the bike. He sets normally and moves his feet in the opposite
direction. Voila, the bike and rider are going backwards, the front wheel is now behind the rear
(driving) wheel.
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"Bill Patterson" <[email hidden]> wrote in message
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Quoted message said:

The rider doesn't turn around on the bike. He sets normally and moves his feet in the opposite
direction. Voila, the bike and rider are going backwards, the front wheel is now behind the rear
(driving) wheel.

I've also seen it done the other way 'round wherein the rider sits or stands astride the top tube
facing the rear of the bike. Makes the handlebars the equivalent of USS (sorta). In fact this was
the first way I ever saw a bike ridden backwards.

<Chas

Quoted post said:

Originally posted by GeoB
> But a little further reflection will show that this has nothing to do
with the bicycle ITSELF going backwards. Note that the bicycle and its dynamics do not care which
way you are facing.

One huge vehicle dynamic difference.

In rws, your steered wheel is going in the opposite direction as the lean.
If fws, your steered wheel is going in the same direction as the lean.

The dynamics of vehicle balance correction are different.

In fws, while in a right turn you are leaning right with your wheel turned right.
If you turn the wheel sharper, you have more forces try to upright you from the lean.

In rws, while in a right turn, you are leaning right with your wheel turned left.
If you turn the wheel sharper, you have more forces trying to accentuate the lean.

Also, sometimes, there is an implementation specific human factors issue: Unless you have complicated linkages, steering is counterintuitive.

Chas said:

I've also seen it done the other way 'round wherein the rider sits or stands astride the top tube
facing the rear of the bike. Makes the handlebars the equivalent of USS (sorta). In fact this was
the first way I ever saw a bike ridden backwards.

Somewhere in the depths of Newsletter Central is an old cycling comic with a double-page item on
Wrong Way Wootton, a man possibly the wrong side of certifiable. He rode a bike thus; a bike fitted
with more luggage than most people would think humanly possible, with a Several of mirrors to permit
forward visibility and with - wait for it - a portable TV where the saddle would be on a more
orthodox bicycle.

I also have a picture of the late Patrick Depailler riding a BMX bike while sitting on the bars
facing backwards, while it was by actions of one Jamie Tatlow doing this in a pub car park that we
discovered that if one clips into SPD pedals backwards, release can only be effected by poking the
internals of the pedals with a screwdriver. The second time he did this, he was left propped against
the wall while the assembled faithless went back in for another pint...

In all these cases, though, the bike was travelling forwards. You haven't been overdoing the
Christmas Spirit, have you Bill? ;-)

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Quoted message said:

One huge vehicle dynamic difference.

Of course. This is what I was trying to say.

Quoted message said:

[RIDING ON A BICYCLE BACKWARDS] is not difficult. I am an over-weight middle-aged balding office-
worker guy and I can do this easily. But a little further reflection will show that [THIS] has
nothing to do with the bicycle ITSELF going backwards. Note that the bicycle and its dynamics do
not care which way you are facing.

Dave,

I have been hitting the Christmas spirit. However, After forward facing rear facing bikes going
forward and backward, Me and the Martini are confused.

It's like Nuclear Power. I believe whoever talks to me last.
===================
Quote:

In all these cases, though, the bike was traveling forwards. You haven't been overdoing the
Christmas Spirit, have you Bill? ;-)

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Bill Patterson said:

Today I saw an amazing sight. One of the engineering design students rode a front drive/rear steer
bike. He then loaned it to a friend who wobbled a little and rode away.

I and many others have ridden a VSWB [1] recumbent that is FWD and both FWS and RWS. [2]

[1] Very Short Wheelbase
[2] <http://www.wisil.recumbents.com/wisil/bbike1.jpg> and
<http://www.wisil.recumbents.com/wisil/hpvbikes97.htm>.

Tom Sherman - Planet Earth

2 wheel steer, quite a feat. Hats off to you.

Bill Patterson (out of town.)