Adam Hart-Davis (front fork)

soup said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

Don't know. BMW (amongst others) have done it for years
on the rear axle of (some of) their motor-cycles, but
I wouldn't risk /my/ life on a single-sided design !

** Phil.

"soup" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?
--

He talks about his bikes here:

http://www.gec.dircon.co.uk/holiday/sway_tower/adam_bikes.html

and on CH4 tomorrow night.

Simon M.

soup said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

Because Mr Burrows likes them that way :-)

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

soup said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

It's not that simple... For the same weight you can have as twice as
much material in the side of the fork you keep, so done right it can
actually be /stronger/ at the same weight, or as strong at less weight.
Note that cars and trucks have single sided wheel supports, and they
seem to do okay with them...

One of my bikes (the Burrows 8 Freight) has a single sided fork and a
single sided rear support too. It's a freight bike so it needs to be
strong, and it is. The Cannondale Lefty fork for their serious mountain
bikes is used because it's lighter at an acceptable level of stength
(which since it's a serious MTB, is pretty strong!).

But as with much engineering, doing it at all and doing it well are two
entirely different things (c.f. disc brakes and suspension). Doing it
well costs money.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Philip TAYLOR said:

Don't know. BMW (amongst others) have done it for years
on the rear axle of (some of) their motor-cycles, but
I wouldn't risk /my/ life on a single-sided design !

FUD. Mike Burrows has single sided supports as one of his common design
trademarks. My Burrows 8 Freight has shown no obvious signs of
weaknesses as it goes about with an extra 50kg (as well as me). MB
appears to know what he's doing, and it's well proven technology,
nothing to be scared of.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

in message <[email hidden]>, soup

(') said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

The strength of a tube (and many other types of strut) increases with
the square of its diameter. So if you double the diameter of a fork
blade you increase its strength by four times, but increase its weight
only twice[1]. So a single, thicker blade is stronger and lighter than
two thinner blades. This is why, for example, the lightest full
suspension mountain bikes in this years world cup series - the ones
which are currently leading the series - use monoblade forks:
<URL:http://www.cannondale.com/bikes/bikeword/MSE1643_165.html>
<URL:http://www.cannondale.com/bikes/04/ce/model-4VP4.html>.

Britain's best known bike designer, Mike Burrows, is also a believer in
monoblades, as can be seen in his 8freight and windcheetah designs:
<URL:http://www.bikefix.co.uk/i-8freight.html>
<URL:http://www.windcheetah.co.uk/>

The other benefit apart from being stronger and lighter is that it makes
it much easier to change tyres and inner tubes.

[1] assuming constant wall thickness; and of course if the wall
thickness is too thin the tube will buckle.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Das Internet is nicht fuer gefingerclicken und giffengrabben... Ist
nicht fuer gewerken bei das dumpkopfen. Das mausklicken sichtseeren
keepen das bandwit-spewin hans in das pockets muss; relaxen und
watchen das cursorblinken. -- quoted from the jargon file

"soup" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

Take a look:
http://www.cannondale.com/bikes/04/ce/model-4VN3.html

USE also make an mtb single bladed sus fork with a linkage that provides
anti-dive properties.

Rgds,
Pete

"Peter B" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

USE also make an mtb single bladed sus fork with a linkage that provides
anti-dive properties.

http://www.bikemagic.com/review/reviewproduct/mps/RGN/2/RCN/50/RPN/13825/v/2
/sp/

Philip TAYLOR said:

soup said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

Don't know. BMW (amongst others) have done it for years
on the rear axle of (some of) their motor-cycles, but
I wouldn't risk /my/ life on a single-sided design !

Like on all cars?

Quoted message said:

** Phil.

Peter Clinch [email hidden] opined the following...

Quoted message said:

FUD. Mike Burrows has single sided supports as one of his common design
trademarks. My Burrows 8 Freight has shown no obvious signs of
weaknesses as it goes about with an extra 50kg (as well as me). MB
appears to know what he's doing, and it's well proven technology,
nothing to be scared of.

Having (At your suggestion) harrassed the great Mr Burrows at the York
rally a few points;

1) The strength increase is fine for monoblade, but you also require a
stronger axle and the forces that can be exerted on the monoblade are
harder to quantify than those in a fork (There are rotational forces
that simply don't exist or are miniscule in a fork that are a serious
concern in a monoblade) - These are my observations.
2) The original (Lotus bike) was for aerodynamic reasons only and
apparently suffered from flex that was tolerable only because it was for
use in a velodrome. - MB
3) The lefty is strong and also removes a certain amount of stiction
because it is easier to line up two tubes than to line up four! - MB
4) The 8Freight and the London Transport bike both have them for
practical reasons (Ease of tyre change). -MB
5) The Ratcatcher has a single mount rear for simplicity of engineering
and a front monoblade because "It's my trademark and people would be
concerned if it wasn't there!" - MB
6) There is _no_ reason to put one on a road bike and several good
reasons not too. - MB

With regard to strength. I'm still not totally convinced since there are
additional forces to make use of that strength but Mr Burrows seems
happy and I'm sure that we'd know about it if the Lefty had failed!

Jon

in message <[email hidden]>, Peter B

(') said:

"soup" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

One of his bikes seems to have a single blade to the front fork
can see the wheel wouldn't have to be removed to change a
tube but an axle only supported at one end seems a lot weaker
than one supported at both ends, so why do it ?

Take a look:
http://www.cannondale.com/bikes/04/ce/model-4VN3.html

USE also make an mtb single bladed sus fork with a linkage that
provides anti-dive properties.

I know. I want one for my Mantra. But it is just a little bit expensive.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; in faecibus sapiens rheum propagabit

Ningi wrote:

[snip]

Quoted message said:

Quoted message said:

Don't know. BMW (amongst others) have done it for years
on the rear axle of (some of) their motor-cycles, but
I wouldn't risk /my/ life on a single-sided design !

Like on all cars?

If a wheel suddenly goes skew on my Saab, I have a
reasonable chance of remaining alive (D.v.); when the
same thing happens on my Suzuki, the chances diminish
to near zero ...

** Phil.

Philip TAYLOR said:

If a wheel suddenly goes skew on my Saab, I have a
reasonable chance of remaining alive (D.v.); when the
same thing happens on my Suzuki, the chances diminish
to near zero ...

But the point is you /are/ "risking your life" with single sided
supports on your Saab, despite the fact you said you'd never do such a
thing. A "reasonable chance" is not certainty, so there is risk. How
often do you see cars (and buses, and trucks, and tractors, and JCBs
etc.) where a wheel has just snapped off?

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch <[email hidden]> wrote in news:ce86h4$hi7$1
@dux.dundee.ac.uk:

Quoted message said:

How
often do you see cars (and buses, and trucks, and tractors, and JCBs
etc.) where a wheel has just snapped off?

I've seen it once, on a 2CV that was in front of us going through roadworks
approaching the Forth Road Bridge. I can't remember which wheel it was, but
it bounced off down the road. The passengers/load was so arranged that the
car remained upright on its three remaining wheels until it could pull over
at the side. Not something I expect to ever see again. Scarey to watch
though.

Graeme

On Wed, 28 Jul 2004 13:38:26 +0100, Peter Clinch <[email hidden]>

Quoted message said:

But the point is you /are/ "risking your life" with single sided
supports on your Saab, despite the fact you said you'd never do such a
thing. A "reasonable chance" is not certainty, so there is risk. How
often do you see cars (and buses, and trucks, and tractors, and JCBs
etc.) where a wheel has just snapped off?

Once. We were in a filling station and heard this clunk as a small flatbed
truck 'fell over' as its wheel rolled off into the road. Luckily the
driver was slowing for the roundabout when it happened.

Colin

Graeme said:

I've seen it once, on a 2CV that was in front of us going through roadworks
approaching the Forth Road Bridge. I can't remember which wheel it was, but
it bounced off down the road. The passengers/load was so arranged that the
car remained upright on its three remaining wheels until it could pull over
at the side. Not something I expect to ever see again. Scarey to watch
though.

Difficult to say whether that was actually a case of snapping off with a
broken axle, or just the wheel nuts not being done up. Probably the
latter though, as if it had the remains of the axle attached it wouldn't
have bounced so well...

I was sipping a mug of tea by a refreshment van in Llanberis Pass once
when a strange noise round the corner was followed by a wheel bouncing
along the road, itself preceding the Mini making said strange noise.
Driver got out with a bemused expression, "it went that way", we told
him, indicating. "What did?"; "Your front wheel", though this time we
indicated where the object missing from his car should go, that followed
by a sort of "[censored]!" expression replacing the bemused one. It
still appeared to have all the mounting paraphernalia except the wheel
nuts...

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Graeme said:

I've seen it once, on a 2CV that was in front of us going through roadworks
approaching the Forth Road Bridge.

I've never seen it done on a 2CV, but certain other Citroen models have
suspension that is designed to cope with the car being run on three wheels.

d.

davek said:

I've never seen it done on a 2CV, but certain other Citroen models have
suspension that is designed to cope with the car being run on three wheels.

All the hydraulic self levelling suspension ones, which would be the DS,
CX, GS, BX, Xantia, XM and probably the C5 and maybe one or two others.
Never done on the smaller models (Xsara or smaller) though IIRC.

M&D used to have a GS. We never ran it on 3 wheels, but nifty features
of the hydraulic suspension included the back never getting extra low
with heavy loads and the ability to raise the ground clearance from the
drivers seat by moving a lever, quite handy on rough tracks strewn with
sump-crackers.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch wrote:

[snip]

Quoted message said:

But the point is you /are/ "risking your life" with single sided
supports on your Saab, despite the fact you said you'd never do such a
thing. A "reasonable chance" is not certainty, so there is risk.

But I was answering in the context of cycling, of which
motor cyling is a variant. Driving a car is a very
different kettle of fish.

** Phil.