Recumbents

Does anyone make a FWD / rear steer recumbent? Seems to me you'd save a lot
of chain length. Perhaps they'd struggle for grip up hills?

Doki wrote:
Does anyone make a FWD / rear steer recumbent?

FWD, certainly. Zox and Flevo are the obvious examples, plus the Very
Serious Speed machinery used at the likes of Battle Mountain is
sometimes FWD (well, it's not like they have to go round hairpin bends...).

Rear steer is a different matter. I think it was in C+ that someone
asked this and Mike Burrows answered it. IIRC he basically said that
what's fine in theory doesn't work quite so well in practice and rear
steer bikes tend to be patronised by people called Koko with large red
noses...

The Flevo is an interesting exception to the usual rules: it doesn't
steer at either wheel but has a hinge in the middle of the bike, and can
be ridden completely no hands as far as steering goes (though bars are
provided to mount brake and gear levers)

Seems to me you'd save a lot
of chain length. Perhaps they'd struggle for grip up hills?

I believe that is an issue with some, though not bad enough to render
the concept useless. I think it's combining the steering with the drive
that causes more headaches.

OTOH, long chains aren't as bad as you might think: less wear when used
on derailleurs, for example, as the angles aren't so bad as you move
across the cassette.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On 21/6/04 3:56 pm, in article , "Peter Clinch"
wrote:

Rear steer is a different matter. I think it was in C+ that someone
asked this and Mike Burrows answered it. IIRC he basically said that
what's fine in theory doesn't work quite so well in practice and rear
steer bikes tend to be patronised by people called Koko with large red
noses...

I was just thinking about this and considering what pushing a rear steer
trolley is like. There is only one word I can think of to desribe the
thought of rear wheel steering on a fast downhill and that is SCARY
(followed by lots of road rash and a stay in hospital).

There is a reason the back wheels follow the front and that is stability.
Rear steering involves the back going it's own way. Interesting...

...d

David Martin wrote:

I was just thinking about this and considering what pushing a rear
steer trolley is like. There is only one word I can think of to
desribe the thought of rear wheel steering on a fast downhill and
that is SCARY (followed by lots of road rash and a stay in hospital).

ISTR that Thrust SSC was rear-steer.

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

On 21/6/04 4:34 pm, in article , "Just zis Guy,
you know?" wrote:

David Martin wrote:

I was just thinking about this and considering what pushing a rear
steer trolley is like. There is only one word I can think of to
desribe the thought of rear wheel steering on a fast downhill and
that is SCARY (followed by lots of road rash and a stay in hospital).

ISTR that Thrust SSC was rear-steer.

For limited values of steer, yes. To get sufficient turning circle you would
need a reasonable degree of rotation on the steered wheel. Thrust type
steering would be fine if there were no corners.

...d

Just zis Guy, you know? typed:
David Martin wrote:

I was just thinking about this and considering what pushing a rear
steer trolley is like. There is only one word I can think of to
desribe the thought of rear wheel steering on a fast downhill and
that is SCARY (followed by lots of road rash and a stay in hospital).

ISTR that Thrust SSC was rear-steer.

But Thrust doesn't have 'steering' as such, it's really just an aid to
staying in a straight line at st00pid speeds ...

--
Paul ...

(8(|) ... Homer Rocks

On Mon, 21 Jun, Just zis Guy, you know? wrote:
David Martin wrote:

I was just thinking about this and considering what pushing a rear
steer trolley is like. There is only one word I can think of to
desribe the thought of rear wheel steering on a fast downhill and
that is SCARY (followed by lots of road rash and a stay in hospital).

ISTR that Thrust SSC was rear-steer.

It was, and when teh engineers proposed it as teh solution to various
problems it was mightily poo-pooed. It'll never work, inherently
unstable, blaah blaah. In fact, read on in the thread for the sort of
comments heaped on teh rear-steer proposal.

They built a steering prototype by taking a mini, locking teh front
wheels straight, detaching teh back axle and substituting a long pylon
with steering wheels on teh back, such that the geometry was a
scaled-down version of the Thrust proposal.

Apparently it steered beautifully, no problem at all, as long all teh
linkages were fully 100% ok and there was no slop in anything.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Just zis Guy, you know? wrote:

ISTR that Thrust SSC was rear-steer.

It was, and afterwards S/L Green is on record as saying that such steering
should in future be confined to forklifts.

There /have/ been some more or less successful FWD/RWS recumbent trikes,
though. The Sturmey-Archer Flying Five and Simon Sanderson's exquisitely
mis-named Panzer were both successful racers in the early 80's, and there
have been production machines from the Jouta brothers in The Netherlands.
However, get it wrong and it will bite - I have the scars to prove it.

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
================================================== =========
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
================================================== =========

On Tue, 22 Jun 2004 13:11:52 +0100, Dave Larrington wrote:

There /have/ been some more or less successful FWD/RWS recumbent trikes,
though.

I would love to try one.

The Sturmey-Archer Flying Five and Simon Sanderson's exquisitely
mis-named Panzer were both successful racers in the early 80's, and there
have been production machines from the Jouta brothers in The Netherlands.
However, get it wrong and it will bite - I have the scars to prove it.

If rear-steering can work, would I be able to ride a bike backwards
downhill? I've been trying (why not?!) and I might practice harder if I
knew that it was possible.

AC

David Martin wrote:
On 21/6/04 3:56 pm, in article , "Peter
Clinch" wrote:

Rear steer is a different matter. I think it was in C+ that someone
asked this and Mike Burrows answered it. IIRC he basically said that
what's fine in theory doesn't work quite so well in practice and rear
steer bikes tend to be patronised by people called Koko with large
red noses...

I was just thinking about this and considering what pushing a rear
steer trolley is like.

Just a case of practice, IME of pushing trolleys with the steering wheels at
the back.

There is only one word I can think of to
desribe the thought of rear wheel steering on a fast downhill and
that is SCARY (followed by lots of road rash and a stay in hospital).

There is a reason the back wheels follow the front and that is
stability. Rear steering involves the back going it's own way.
Interesting...

It wouldn't be difficult to castor the rear wheels so that they return to
straight ahead of their own accord. The opposite occurs in a car when you
reverse, so it gives you the impression that rear steer is much more
unstable than it has to be.