Linking forward and rear suspension

I was looking at a picture of a Whyte PRST1 earlier today, and musing
as one does... The Whyte uses quite similar suspension units for both
front and rear suspesion:
URL: http://www.whytebikes.com/whyte-2004...1side72dpi.jpg

and what I was musing about was the Citroen Deux Chevaux and the
original Issigonis designed Austin Mini. The 2cv had a single
suspension unit on each side of the car which linked the front and
rear swing-arms; the original mini used 'hydrolastic' suspension units
where the oil reservoir in the forward suspension unit was linked with
a pipe to the oil reervoir in the rear unit on the same side. This was
a conscious imitation of the principle of the 2cv system while
avoiding the Citroen patents. The hydropneumatic Citroens - DS, GS,
SM, BX, CX, XM, Xantia and C5 - have of course more complex hydraulic
interconnection of the suspension units but that isn't what I'm
thinking of here.

The point is that on both the 2cv (a car I love - in my opinion the
world's most under-rated sportscar) and the early minis the scheme
worked extremely well to limit pitch, giving a perception of a much
smoother ride. When the front hit a bump and the front suspension
compressed the rear suspension would extend, keeping the body of the
vehicle relatively level.

It struck me that this principal, if applied to mountain bikes, would
possibly give a steadier and more controllable ride particularly over
fast rough sections, and that with modern air/oil suspension struts it
would not actually be that hard to rig up, and would add very little
in weight.

So the question is, who has tried it and what were the results? I've
done a quick web search but haven't come up with anything... but the
idea is so obvious _someone_ must have tried it, surely?

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

;; this is not a .sig

http://www.whytebikes.com/whyte-2004...1side72dpi.jpg
Is it just me, or is there something not right about the lacing on these
wheels?

"Simon Brooke" wrote in message
. uk...
I was looking at a picture of a Whyte PRST1 earlier today, and musing
as one does... The Whyte uses quite similar suspension units for both
front and rear suspesion:
URL: http://www.whytebikes.com/whyte-2004...1side72dpi.jpg


The Bimota Tesi D1 uses dual swingarms.

http://www.bikepics.com/pictures/042949/

--
Phil, Squid-in-Training

Stu Ted writes:

http://www.whytebikes.com/whyte-2004...1side72dpi.jpg

Is it just me, or is there something not right about the lacing on
these wheels?

It's just you. That's conventional 23 x 3. How about exposing your
doubts. What is it you find odd?

Jobst Brandt

Simon,

The original BMC mini used rubber for a suspension medium.
The later ones, IIRC 1965 and later used the Hydrolastic suspension
setup. In rallying and racing any hydrospastic minis I have seen were
converted to a dry suspension.

The interlinking of suspension does have some merit to contol roll, dive
and squat in the automotive world. Such active systems do add complexity
and to work well need microprocessor control and a host of sensors.

I really don't see it being much use with the light weight, relatively
short wheelbase and varying conditions faced by an offroad bicycle.

That being said I'm sure somebody with time on their hands and some
hose, double acting hydraulic cylinders and a couple of diaphramed
air/oil reservoirs could have hours of entertainment.

Marcus

In article , stu wrote:
http://www.whytebikes.com/whyte-2004...1side72dpi.jpg
Is it just me, or is there something not right about the lacing on these
wheels?

They're the new VariCross(tm) wheels from VariSpoke, scheduled to be
released in early April. Notice the hubs are 100% hidden in the
picture in accordance with the VariSpoke pre-release product rules.

Greg
--
Gregory S. Sutter "How do I read this file?"
"You uudecode it."
http://zer0.org/~gsutter/ "I I I decode it?"

It's just you. That's conventional 23 x 3. How about exposing your
doubts. What is it you find odd?

Jobst Brandt

Happy to take your word on it
What I was looking at was how, on one half of the wheel you 3 places where 4
spokes cross almost at the same spot, yet on the other half of the wheel it
looks nothing like that. I use 38 myself, so I guess I have just never
noticed this before.
thanks
stu

stu wrote:

It's just you. That's conventional 23 x 3. How about exposing your
doubts. What is it you find odd?

Jobst Brandt


Happy to take your word on it
What I was looking at was how, on one half of the wheel you 3 places where 4
spokes cross almost at the same spot, yet on the other half of the wheel it
looks nothing like that. I use 38 myself, so I guess I have just never
noticed this before.

I certainly find it odd that Jobst considers 23 spokes to be conventional
and that you use 38. I think the appearance that's bothering you is
just due to the perspective not being quite perpendicular to the wheel and
lining up some left-side and right-side spokes.

On Wed, 26 Nov 2003 11:04:10 +1100, "stu" wrote:
http://www.whytebikes.com/whyte-2004...1side72dpi.jpg
Is it just me, or is there something not right about the lacing on these
wheels?

Apart from there being something fundamentally wrong with the whole
bike? It appears that it could have been done better if they had
thought even _more_ outside the box. Although I can't visualize it
at the moment, I imagine there must be a _much_ simpler solution to
the idea of putting both shock absorbers on the frame, rather than
the front in the fork.

However, even so, doesn't the fork represent unsprung weight, which,
IIRC, should be minimized for better handling? Or is that not true
of bikes?

Okay, back to the question: I'm no wheel expert, but the spoke
lacing does appear a bit odd; I seem to see parallel spokes where I
shouldn't, and such pairs aren't evenly spaced from other such pairs
either.

It does appear to have very low gearing, though. I like that in a
gnarly off-road bike...especially if it also appears to weigh 50
pounds. (The site says "Weight 27.8lbs fully built!")
--
Rick Onanian

"
I certainly find it odd that Jobst considers 23 spokes to be conventional
and that you use 38.

lol oops I noticed Jobst's typo, lucky I didnt have a go at him about it hey
lol

I think the appearance that's bothering you is
just due to the perspective not being quite perpendicular to the wheel and
lining up some left-side and right-side spokes.


yes you are right, l went and had another look at my wheels and they do the
same thing. l had throught about that before l posted but l didnt find the
right angel.
thanks again
stu
(who must look more carefully next time)
and install his spell check