front fender question

[Jim Bianchi]

Many years ago, the Italian firm of MotoGuzzi (among others)
experimented with what came to be called 'dustbin fairings' for the front
wheels of their roadracing motorcycles. These would fully enclose the entire
wheel, leaving only a small bit open at the bottom where the wheel touched
the ground, and also completely covered the sides. While fairly successful,
they were also prone to sidewinds blowing the machine off course with the
resulting accident potential. As a result, these full coverage front fenders
were (and are still) banned by all motorcycle roadracing organisations.

My question: Obviously, this would be more than a hinderance than a
help in any kind of off road riding, but do aerodynamics count for enough
that such a scheme (extremely lightweight of course) might be of help on a
roadracing bicycle?

--
[email protected]

"There are only 10 kinds of people in the world;
those who understand binary, and those who don't."

 

[Ron Hardin]

Jim Bianchi wrote:
>
> Many years ago, the Italian firm of MotoGuzzi (among others)
> experimented with what came to be called 'dustbin fairings' for the front
> wheels of their roadracing motorcycles. These would fully enclose the entire
> wheel, leaving only a small bit open at the bottom where the wheel touched
> the ground, and also completely covered the sides. While fairly successful,
> they were also prone to sidewinds blowing the machine off course with the
> resulting accident potential. As a result, these full coverage front fenders
> were (and are still) banned by all motorcycle roadracing organisations.
>
> My question: Obviously, this would be more than a hinderance than a
> help in any kind of off road riding, but do aerodynamics count for enough
> that such a scheme (extremely lightweight of course) might be of help on a
> roadracing bicycle?
>
> --
> [email protected]
>
> "There are only 10 kinds of people in the world;
> those who understand binary, and those who don't."

The drag from spokes advancing (at twice the speed of the bicycle) into a
quartering headwind must be pretty big. A fairing avoids that (but there's
no reason to fair the bottom half. At the very bottom the spokes are standing
still and the fairing is not, so the fairing increases drag! Below the
midline the spokes are going slower than the fairing.

There's some drag too from the air trapped between wheel and fairing. Perhaps
that's only viscous drag, which is not square-law.
--
Ron Hardin
[email protected]

On the internet, nobody knows you're a jerk.

 

[John Forrest Tomlinson]

On Tue, 18 Oct 2005 21:31:34 GMT, [email protected] (Jim Bianchi) wrote:

>
>but do aerodynamics count for enough
>that such a scheme (extremely lightweight of course) might be of help on a
>roadracing bicycle?

There are front disk wheels that allow the rider to go faster. But
they are rarely used on the road due to handling issue.

JT


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[Werehatrack]

On Tue, 18 Oct 2005 21:31:34 GMT, [email protected] (Jim Bianchi) wrote:

> Many years ago, the Italian firm of MotoGuzzi (among others)
>experimented with what came to be called 'dustbin fairings' for the front
>wheels of their roadracing motorcycles. These would fully enclose the entire
>wheel, leaving only a small bit open at the bottom where the wheel touched
>the ground, and also completely covered the sides. While fairly successful,
>they were also prone to sidewinds blowing the machine off course with the
>resulting accident potential. As a result, these full coverage front fenders
>were (and are still) banned by all motorcycle roadracing organisations.
>
> My question: Obviously, this would be more than a hinderance than a
>help in any kind of off road riding, but do aerodynamics count for enough
>that such a scheme (extremely lightweight of course) might be of help on a
>roadracing bicycle?

Any fender or fairing increases the weight and frontal area; this is
generally viewed as a Very Bad Thing. To allow enough space for
normal wheel flex, such a fairing could easily double and possibly
triple the aspect of the wheel it enclosed. Noting that the closest
approximation to this in aerodynamic effects is a disc wheel, I will
observe that disc wheels are typically used only on the rear in road
racing, and are not particularly common even there.

Do not allow this to dissuade you from sinking large amounts of money
into developing a similar product and marketing it widely. Some of us
are desperate for fresh amusements.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Jim Bianchi]

On Wed, 19 Oct 2005 02:05:44 GMT, Werehatrack wrote:
>On Tue, 18 Oct 2005 21:31:34 GMT, [email protected] (Jim Bianchi) wrote:
>
>> Many years ago, the Italian firm of MotoGuzzi (among others)
>>experimented with what came to be called 'dustbin fairings' for the front
>>wheels of their roadracing motorcycles. These would fully enclose the entire
>>wheel, leaving only a small bit open at the bottom where the wheel touched
>>the ground, and also completely covered the sides. While fairly successful,
>>they were also prone to sidewinds blowing the machine off course with the
>>resulting accident potential. As a result, these full coverage front fenders
>>were (and are still) banned by all motorcycle roadracing organisations.
>>
>> My question: Obviously, this would be more than a hinderance than a
>>help in any kind of off road riding, but do aerodynamics count for enough
>>that such a scheme (extremely lightweight of course) might be of help on a
>>roadracing bicycle?
>
>Any fender or fairing increases the weight and frontal area; this is
>generally viewed as a Very Bad Thing. To allow enough space for
>normal wheel flex, such a fairing could easily double and possibly
>triple the aspect of the wheel it enclosed. Noting that the closest
>approximation to this in aerodynamic effects is a disc wheel, I will
>observe that disc wheels are typically used only on the rear in road
>racing, and are not particularly common even there.
>
>Do not allow this to dissuade you from sinking large amounts of money
>into developing a similar product and marketing it widely. Some of us
>are desperate for fresh amusements.

Heh. No thanks, really. This was just an arrant thought that I threw
out. Your (and others') reaction answered me very well. Thank you.

However, if I did do this, I certainly have the name for it. [grin]

--
[email protected]

"There are only 10 kinds of people in the world;
those who understand binary, and those who don't."

 

[Jasper Janssen]

On Tue, 18 Oct 2005 21:31:34 GMT, [email protected] (Jim Bianchi) wrote:

> Many years ago, the Italian firm of MotoGuzzi (among others)
>experimented with what came to be called 'dustbin fairings' for the front
>wheels of their roadracing motorcycles. These would fully enclose the entire
>wheel, leaving only a small bit open at the bottom where the wheel touched
>the ground, and also completely covered the sides. While fairly successful,
>they were also prone to sidewinds blowing the machine off course with the
>resulting accident potential. As a result, these full coverage front fenders
>were (and are still) banned by all motorcycle roadracing organisations.
>
> My question: Obviously, this would be more than a hinderance than a
>help in any kind of off road riding, but do aerodynamics count for enough
>that such a scheme (extremely lightweight of course) might be of help on a
>roadracing bicycle?

Ya gotta finish before you can win. Being blown directly off the mountain
rather than following the road doesn't help in that regard.

The World Solar Challenge cars have full fairings on all three (usually)
wheels, and I rather suspect they use bike wheels and tyres. They're the
right sort of size, and the weight loads and limitations agree fairly well
with (heavy-duty) bike wheels.

Jasper

 

[JeffWills]

Jim Bianchi wrote:
> Many years ago, the Italian firm of MotoGuzzi (among others)
> experimented with what came to be called 'dustbin fairings' for the front
> wheels of their roadracing motorcycles. These would fully enclose the entire
> wheel, leaving only a small bit open at the bottom where the wheel touched
> the ground, and also completely covered the sides. While fairly successful,
> they were also prone to sidewinds blowing the machine off course with the
> resulting accident potential. As a result, these full coverage front fenders
> were (and are still) banned by all motorcycle roadracing organisations.
>
> My question: Obviously, this would be more than a hinderance than a
> help in any kind of off road riding, but do aerodynamics count for enough
> that such a scheme (extremely lightweight of course) might be of help on a
> roadracing bicycle?
>

Hmmm... horses for courses. On a hilly, curvy course, the weight and
manuverability penalty could be more than the advantage the fairing
provides. On a flat course, the advantage goes to aerodynamics. One
version of an "upright" fairing was used at this year's WHPSC by Mike
Mowett:
http://www.recumbents.com/wisil/whpsc2005/resultsthursday.htm
It's a basic windshield with a fabric body sock.

For most bicycle road races, pack tactics and strategy could overwhelm
any advantage aerodynamic device- or they might not. It's a moot point
anyway, since purely aerodynamic devices are banned by the UCI.

Full-coverage fairings on upright bikes were tried back in the '70's.
Not only were these wind-sensitive, they developed quite a bit of lift
in a cross wind. A rider falling to his side at speed might discover
that he and his faired bicycle took flight. This caused several
spectacular crashes at the early IHPSC races. Full-fairing recumbents
are still quite wind-sensitive, but they don't fly as far.

Another example: at the last Race Across Oregon (a RAAM qualifier), a
team of recumbent riders was entered. They used several different
styles of bikes and trikes i.e. lightweight bikes for climbing, stable
trikes for twisty descents, and a faired, 70-pound trike for long
straight runs. They held their own on the climbs (occasionally passing
upright riders) and gained time by using the faired trike on the flats.


The recumbent team won the event outright- and it ain't flat out there.
The course includes 38,000 feet of climbing in 528 miles and finishes
at 6,000 feet altitude.

The trike is owned by John Williams, who holds a couple course records
for 40K time trials: http://www.emeraldvelo.org/state_tt.html , so he's
not a slow rider. However, the fairing turns him into Superman.

Jeff

 

[Jim Bianchi]

On 19 Oct 2005 14:36:17 -0700, JeffWills wrote:
>Jim Bianchi wrote:
>> Many years ago, the Italian firm of MotoGuzzi (among others)
>> experimented with what came to be called 'dustbin fairings' for the front
>> wheels of their roadracing motorcycles. These would fully enclose the entire
>> wheel, leaving only a small bit open at the bottom where the wheel touched
>> the ground, and also completely covered the sides. While fairly successful,
>> they were also prone to sidewinds blowing the machine off course with the
>> resulting accident potential. As a result, these full coverage front fenders
>> were (and are still) banned by all motorcycle roadracing organisations.
>>
>> My question: Obviously, this would be more than a hinderance than a
>> help in any kind of off road riding, but do aerodynamics count for enough
>> that such a scheme (extremely lightweight of course) might be of help on a
>> roadracing bicycle?
>>
>
>Hmmm... horses for courses. On a hilly, curvy course, the weight and
>manuverability penalty could be more than the advantage the fairing
>provides. On a flat course, the advantage goes to aerodynamics. One
>version of an "upright" fairing was used at this year's WHPSC by Mike
>Mowett:
>http://www.recumbents.com/wisil/whpsc2005/resultsthursday.htm
>It's a basic windshield with a fabric body sock.
>
>For most bicycle road races, pack tactics and strategy could overwhelm
>any advantage aerodynamic device- or they might not. It's a moot point
>anyway, since purely aerodynamic devices are banned by the UCI.

Details, details. [grin] This and other responses have been most
enlightning. Thanks muchly..

--
[email protected]

"There are only 10 kinds of people in the world;
those who understand binary, and those who don't."

 

[Tomek Li]

"Jim Bianchi" <[email protected]> wrote in message
news:[email protected]...

> My question: Obviously, this would be more than a hinderance than a
> help in any kind of off road riding, but do aerodynamics count for enough
> that such a scheme (extremely lightweight of course) might be of help on a
> roadracing bicycle?
>

The aerodynamic drag caused by spokes moving forward has been already
reduced pretty much with introduction of wheels with smaller number of
spokes. While durability of 8 spoked wheels can be questioned, they are
definitely superior in terms od weight and drag. Installation of
aerodynamical enclosure for the front wheel would be IMHO solving a
nonexisting problem.

Cheers,

Tomek Li

 

[Jim Bianchi]

On Thu, 20 Oct 2005 16:39:48 +0100, Tomek Li wrote:
>"Jim Bianchi" <[email protected]> wrote in message
>news:[email protected]...
>> My question: Obviously, this would be more than a hinderance than a help
>> in any kind of off road riding, but do aerodynamics count for enough that
>> such a scheme (extremely lightweight of course) might be of help on a
>> roadracing bicycle?
>>
>The aerodynamic drag caused by spokes moving forward has been already
>reduced pretty much with introduction of wheels with smaller number of
>spokes. While durability of 8 spoked wheels can be questioned, they are
>definitely superior in terms od weight and drag. Installation of
>aerodynamical enclosure for the front wheel would be IMHO solving a
>nonexisting problem.

Interesting point, one that suggests a (probably) weird question:
How big would a spoke need to be in order to be able to have only three?
Could this be done using sooper high tech material, and would the result
still be small and light enough so as to not present problems of their own?

Disc wheels have already been mentioned, as have the adverse
problems they present -- so I'm not thinking of them.

Further thought: Has any research been done about the use of one
piece wheels? (NOT disc wheels -- one piece wheels with pseudospokes.) As
sports car roadracers found, they look kewl, and provide cooling to the
brakes, but they do flex, they are heavy (when compared to a one piece cast
wheel), and require a lot of maintenance. So why not 'mag' wheels for racing
bicycles?

Or has this been investigated already and the idea shown to be the
product of a disordered mind?

--
[email protected]

"There are only 10 kinds of people in the world;
those who understand binary, and those who don't."

 

[Ryan Cousineau]

In article <[email protected]>,
[email protected] (Jim Bianchi) wrote:

> Many years ago, the Italian firm of MotoGuzzi (among others)
> experimented with what came to be called 'dustbin fairings' for the front
> wheels of their roadracing motorcycles. These would fully enclose the entire
> wheel, leaving only a small bit open at the bottom where the wheel touched
> the ground, and also completely covered the sides. While fairly successful,
> they were also prone to sidewinds blowing the machine off course with the
> resulting accident potential. As a result, these full coverage front fenders
> were (and are still) banned by all motorcycle roadracing organisations.
>
> My question: Obviously, this would be more than a hinderance than a
> help in any kind of off road riding, but do aerodynamics count for enough
> that such a scheme (extremely lightweight of course) might be of help on a
> roadracing bicycle?

The short answer is that it doesn't matter, because any sort of fairing
of this type is banned in UCI road races, which is to say just about
every bicycle road race of any consequence.

Human-powered vehicle (HPV) racing, however, is another story. The main
event in HPV racing is the 200m flying trial, which is the de facto HPV
land speed record.

http://www.ihpva.org/hpva/hpvarec7.html#nom01

The Varna Diablo II, designed by George Georgiev, is the current
record-holder at 81 mph, ridden by Sam Whittingham

The vehicles used for HPV records are fully enclosed recumbent bicycles
with very aerodynamic shells.

I found an account by Whittingham of his ride in the Diablo while
setting the hour record: he notes that his sustained power output while
riding in this thing is measurably less than when riding an upright bike
or an open HPV, a combination of the constrained position and heat
issues.

What it looks like:

http://www.popsci.com/popsci/how20/7ccf7f1727cb6010vgnvcm1000004eecbccdrc
rd/2.html

Aerodynamics are hugely important for any bicycle. But sidewinds are
also a problem.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

 

[Jasper Janssen]

On Thu, 20 Oct 2005 20:10:39 GMT, [email protected] (Jim Bianchi) wrote:

>So why not 'mag' wheels for racing bicycles?

Downgroup a bit, there's a question from someone who was using bike mag
wheels on his horse-racing chariot (and murdered the bearings, but
whatever). He says the brand was popular in the late 90s.

Jasper

 

[Ryan Cousineau]

In article <[email protected]>,
[email protected] (Jim Bianchi) wrote:

> On Thu, 20 Oct 2005 16:39:48 +0100, Tomek Li wrote:
> >"Jim Bianchi" <[email protected]> wrote in message
> >news:[email protected]...
> >> My question: Obviously, this would be more than a hinderance than a help
> >> in any kind of off road riding, but do aerodynamics count for enough that
> >> such a scheme (extremely lightweight of course) might be of help on a
> >> roadracing bicycle?
> >>
> >The aerodynamic drag caused by spokes moving forward has been already
> >reduced pretty much with introduction of wheels with smaller number of
> >spokes. While durability of 8 spoked wheels can be questioned, they are
> >definitely superior in terms od weight and drag. Installation of
> >aerodynamical enclosure for the front wheel would be IMHO solving a
> >nonexisting problem.
>
> Interesting point, one that suggests a (probably) weird question:
> How big would a spoke need to be in order to be able to have only three?
> Could this be done using sooper high tech material, and would the result
> still be small and light enough so as to not present problems of their own?

I believe the sooper high tech material of choice is carbon fibre, but
plastic works too:

http://www.cyclingnews.com/teamtech04.php?id=tech/2004/probikes/webcor_le
mond2

The gist is that tri-spoke wheels and deep section aero wheels (think
Zipp 808s) are very fast, but have "sail" problems similar to those of
disc wheels (though less dramatic).

http://www.cbike.com/zipp_wheels.htm#808

> Disc wheels have already been mentioned, as have the adverse
> problems they present -- so I'm not thinking of them.
>
> Further thought: Has any research been done about the use of one
> piece wheels? (NOT disc wheels -- one piece wheels with pseudospokes.) As
> sports car roadracers found, they look kewl, and provide cooling to the
> brakes, but they do flex, they are heavy (when compared to a one piece cast
> wheel), and require a lot of maintenance. So why not 'mag' wheels for racing
> bicycles?

one-piece wheels are heavy. They had a brief stint of popularity in BMX,
mainly I think because the plastic 5-spoke wheels couldn't be knocked
out of true, and looked cool.

> Or has this been investigated already and the idea shown to be the
> product of a disordered mind?

Broadly speaking, yes.

In TT events, a variety of funky front wheels are used, but they can
basically be described as several varieties of composite wheel with 3-5
solid spokes; a bunch of deep-section wheels with aero spokes, and
everything else, which isn't much.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos