Fairings for upright bikes?

[Rob Morley]

In article <[email protected]>
<[email protected]> wrote:
> Rob Morley wrote:
> > In article <[email protected]>
> > <[email protected]> wrote:
> > <snip>
> > > Jobst brought up the braking, not me. I was talking about stability
> > > concerns and tires breaking loose when reaching limits of traction in
> > > cornering.
> >
> > Perhaps you should have said that then, rather than expecting us to be
> > psychic.
>
> To further the discussion both you and Jobst could've said that I was
> including two kinds of skidding under one description, one which fit
> the other which didn't. Jobst was funny in disavowing an important part
> of one of his own major essays to go after my overly broad remark.
>
You said "For instance, some people think they can control sliding rear
and/or front wheels but in general once they break loose all bikes GO
DOWN promptly." Maybe you ride differently than I do, but in general if
one of my wheels slides it's because I'm braking, not because I'm
exceeding the cornering limit. I think the only times I've had a wheel
break away uncontrollably have been when there was diesel on the road or
a wet manhole cover that I didn't see, otherwise I tend to ride within
the limits of the bike and the road conditions.

 

[[email protected]]

Rob Morley wrote:
> In article <[email protected]>
> <[email protected]> wrote:
> > Rob Morley wrote:
> > > In article <[email protected]>
> > > <[email protected]> wrote:
> > > <snip>
> > > > Jobst brought up the braking, not me. I was talking about stability
> > > > concerns and tires breaking loose when reaching limits of traction in
> > > > cornering.
> > >
> > > Perhaps you should have said that then, rather than expecting us to be
> > > psychic.
> >
> > To further the discussion both you and Jobst could've said that I was
> > including two kinds of skidding under one description, one which fit
> > the other which didn't. Jobst was funny in disavowing an important part
> > of one of his own major essays to go after my overly broad remark.
> >
> You said "For instance, some people think they can control sliding rear
> and/or front wheels but in general once they break loose all bikes GO
> DOWN promptly." Maybe you ride differently than I do, but in general if
> one of my wheels slides it's because I'm braking, not because I'm
> exceeding the cornering limit. I think the only times I've had a wheel
> break away uncontrollably have been when there was diesel on the road or
> a wet manhole cover that I didn't see, otherwise I tend to ride within
> the limits of the bike and the road conditions.

So how are you advancing the thread? I was talking about bike
stability. I said at the limits of stability it doesn't matter what
bike you're riding. There are two limits: braking and cornering. My
Jobst quote applied to one.

My point stands that bike stability is multifaceted. Your point is?

---JP

 

[Bill Bushnell]

In article <[email protected]>,
[email protected] wrote:
> For most of the length, the surface is not "improved." It started life
> as a path for mules pulling boats, and it's never been graded. It's
> often just a rough double track through the forest. Personally, I
> really enjoyed it. But my wife and daughter were pretty displeased at
> the surface.

I don't know too many road bikers (or recumbent riders) who are
comfortable riding their steeds on dirt roads. Those who do enjoy it
manage to look beyond the technical challenges such as they may be and
enjoy the variety and other benefits of getting off the main highways,
even if they have to walk some sections or ride slowly.

> BTW, when you talk about climbing 2000 feet with a recumbent - or any
> bike - you should state something about the percent grade. As I said,
> Appalachian grades are extreme. Western grades are usually much, much
> gentler, IME. We climbed grades in Maryland and Pennsylvania that had
> us standing and groaning to move uphill in our 20 inch low gears!
> Those roads were paved. If they weren't, we'd have been off the bikes
> and pushing.

You may be thinking of the gentle grades of the main highways through
the Rockies. Not all western grades are gentle. One such notorious
grade (The Wall) is on Mattole Rd. near Cape Mendocino in Northern
California. Not only is it steep (20% grade), but winds are strong and
unpredictable along this unsheltered part of the coast. Winter storms
off the Pacific Ocean often make landfall here. This picture (and
others in the album) show this area during uncommonly good weather.

http://tinyurl.com/pdu9k

The climb up Clear Creek Rd. in the Diablo Range of central California
west of Coalinga isn't particularly steep, except for a couple of short
steep uphill sections (~15% grade) where a loose surface had us walking.
The rest of the climb near the top of the ridge reaches about a 10%
grade, maximum, which was all rideable for us.

http://tinyurl.com/pa8uo

The descent on the north side of the ridge has grades exceeding 20% in
places. This was all rideable on our bikes (LWB recumbents).

http://tinyurl.com/qsawy
http://tinyurl.com/lxnzw

--
Bill Bushnell
http://pobox.com/~bushnell/

 

[[email protected]]

PS: Something not brought up here (in addition to the subject, most of
the time) is the idea of partial fairings which I mention. (One of the
hijackings of this thread involved full fairings.)

A recumbent is a good format for full fairing and max speeds.

That's not what this thread is about. It's about convenient speed
boosts (and other added function) for upright bikes thanks to simple
partial fairings.

One thing worth noting in this respect is that the world of partial
fairings is a complex one.

Furthermore, modern bikes with aerobars and aero-bladed-deep-section
wheels are darn aero.

Roughly speaking, here are some CdA to consider:

loaded touring bike CdA = probably 2
standard citybike = 1
upright race bike on tops CdA = .5
upright racer in the drops = .3
short wheelbase recumbent unfaired = .3
tribike with disks = .3-.2
lowracer recumbent = .2
tailfaired lowracer = .15
fully faired HPV = .03

So that in the range of street legal sport bikes, we're talking a good
CdA of .2 for both uprights and 'bents. When unfaired a fast upright
bike isn't all that far behind a fast recumbent. (The Obree superman
position is very close to lowracer CdA, but superman isn't street
safe.)

What happens if an already aero upright is partially faired with
quality shapes front and rear that integrate with an aero? With aero
helmet, batwing jersey and aeropedals? I've NEVER seen a number for
something like that. A full fairing on an upright is .1 CdA. Other
fairings tested are primitive.

Basically the direction I suggest could maybe bring a
commuting/loaded-touring rig from a CdA of 2 down to .2. The average
rider could really notice that! Or it could bring a sport bike of .5-.3
down to .15---also probably a nice improvement. But I don't really know
what kind of MPH gains we're talking. Once again: this is all in the
area of partial fairings which is much murkier than the full fairing
sector.

JP

 

[[email protected]]

[email protected] wrote:
>
>
> What happens if an already aero upright is partially faired with
> quality shapes front and rear that integrate with an aero? With aero
> helmet, batwing jersey and aeropedals? I've NEVER seen a number for
> something like that. A full fairing on an upright is .1 CdA. Other
> fairings tested are primitive.
>
> Basically the direction I suggest could maybe bring a
> commuting/loaded-touring rig from a CdA of 2 down to .2. The average
> rider could really notice that! Or it could bring a sport bike of .5-.3
> down to .15---also probably a nice improvement. But I don't really know
> what kind of MPH gains we're talking. Once again: this is all in the
> area of partial fairings which is much murkier than the full fairing
> sector.

Have you considered experimenting to find out?

Hot wire foam cutters are simple devices. I built one once in less
than an hour.

ISTM you could laminate some cheap beadboard to get suitably thick
blocks, sculpt it into shape with a hot wire, duct tape it to a bike,
and get come quick and dirty data by measuring your terminal velocity
on a long 5% grade. Do this with the original bike, to compare results
with different partial fairings.

With stryofoam, the weight increase would be negligible, but if you
thought it a problem, you could add a few pounds to the "original" bike
to compensate. Do the test in early morning, for calm winds.

If you don't detect a significant difference on a 5% grade, it's
probably a negligible effect and not worth the trouble.

If you found a significant difference, you could either report your
results here, or keep quiet, mold the device in some composite, and get
marketing!

- Frank Krygowski

 

[[email protected]]

[email protected] wrote:
> [email protected] wrote:
> >
> > What happens if an already aero upright is partially faired with
> > quality shapes front and rear that integrate with an aero? With aero
[ ]
>
> Have you considered experimenting to find out?
[ ]
> If you found a significant difference, you could either report your
> results here, or keep quiet, mold the device in some composite, and get
> marketing!
>
> - Frank Krygowski

Well, sure, and I posted my results article in this thread a few times
already: http://www.outyourbackdoor.com/OYB8/bikes/bikeaerobag.html .

I found plenty of gains. But my set-up was darn crude. Anyone with a
real shop and real molding fiber/carbon skills could do far better.

I still have my old test pannier-fairing items. Maybe when I get some
time someday I can use them as molds and make my own.

I'm already running a small biz (bike book publishing) and I can tell
you that a product launch is superhard. And that it's smart to not
reinvent the wheel---I do books. Dozens of other folks out there do
carbon/fiber molding R&D. But ya never know. It's just hard to believe
that out of the millions of hard-fast sport miles being ridden that I'm
the only one in the past 10 years who has tried to help uprighters
boost their speed (and utility) in this way. If I could get a clone,
I'd be happy to have him launch a new product line, though. : )

My main first thread query was: What's been done lately? I've had my
article-report online for 10 years. There should've been huge gains
made since then. So much more is being done now in carbon, for
instance.

--JP

 

[David Damerell]

Quoting Call me Bob <[email protected]>:
>Here in the UK we have a series of national and local routes set up by
>a group called Sustrans, which are notorious for (amongst other
>things) surprising cyclists with poor surfaces.

I was unpleasantly surprised on NCN #1 between Scarborough and Whitby -
not merely generally by the surface, which means it is slower to go up 20
miles of disused railway line than 18 miles of Cornwall-grade terrain -
but, at one point, to come over a crest to find a sudden patch of mud and
potholes. Pure luck not to pancake there, really.
--
OPTIONS=name:Kirsty,menustyle:C,female,lit_corridor,standout,time,showexp,hilit
e_pet,catname:Akane,dogname:Ryoga,fruitkonomiyaki,pickup_types:"!$?=/,scores:
5 top/2 around,color,boulder:0,autoquiver,autodig,disclose:yiyayvygyc,pickup_bu
rden:burdened,!cmdassist,msg_window:reversed,!sparkle,horsename:Rumiko,showrace

 

[David Damerell]

Quoting <[email protected]>:
>Them highwheels were oh so stable, huh?

Well, sideways, yes. They're prone to forwards tipover because of the
position of the centre of gravity, but a penny-farthing can crawl forward
at well below walking pace where a conventional upright would be twisting
the front wheel desperately to stay upright.
--
OPTIONS=name:Kirsty,menustyle:C,female,lit_corridor,standout,time,showexp,hilit
e_pet,catname:Akane,dogname:Ryoga,fruitkonomiyaki,pickup_types:"!$?=/,scores:
5 top/2 around,color,boulder:0,autoquiver,autodig,disclose:yiyayvygyc,pickup_bu
rden:burdened,!cmdassist,msg_window:reversed,!sparkle,horsename:Rumiko,showrace

 

[Peter Clinch]

[email protected] wrote:

> I think you're understimating the broad range of design exploration in
> the 1860s through 1900s. There were enough variations in design to
> allow plenty of testing the effect of crank-to-saddle fore-aft
> postions, including some early models with cranks far forward of the
> axle. We gradually evolved to the "knee over pedal spindle" rule of
> thumb because it worked, not because we were imitating horses.

But "worked" in the context of a big pile of compromises. Trying to sit
on something while moving your legs either side of it requires
compromises to start with, it isn't optimised for anatomy.

> For about 99% of the biking population, the only advantage of a
> recumbent would be comfort.

And the market for "comfort bikes" is a clear demonstration that
recumbents could have a bigger market share if things like costs and
awareness were equal.

> That's balanced by lower stability on
> rough surfaces

That's like saying that a road bike or classic tourer is basically not
much use because it's less stable than alternatives on rough ground! I
live next to a rough lane so if it were a /problem/ I'd always have to
walk the last 100m home, and I'd sell the 'bent. But it isn't, and I don't.

> more difficulty climbing hills,

This is overstated. I can get up hills fine and I live in a hilly
place. It's trickier if the bike is heavier, and they often are, but
that is /not/ a given.

> less visibility in traffic

Your "less visibility in traffic" is my "WTF factor, get given lots more
space in traffic". Recumbents not only get seen, but they don't get
ignored. Mine has the seat at car driver eye level, which gives me
better eye contact than my uprights.

> more difficulty storing & transporting by car, bus, train etc,
> more difficulty carrying up stairs

True.

> or just walking the bike

Mine is just as easy to walk as any of my uprights. All 'bents are not
created equal. It is a common misconception that they're all alike, but
that's even less true than assuming all uprights are.

> more
> difficulty finding certain repair parts, and of course cost.

Cost, yes, but repair parts is overstated. Aside from the frame and the
seat, which typically don't go wrong, they tend to use the same parts as
uprights. A lot of the reason they're not more popular is FUD.

> Recumbents are really interesting, from a "design challenge"
> standpoint. They're fun to ride, as a change of pace. But the overall
> balance of advantages & disadvantages clearly goes to the upright bike.

The /perception/ is as above, the realities, assuming you have the
capital cost to outlay (and I grant you many don't) is much closer than
most people imagine. To me they're just bikes, to a lot of people
they're "obviously" completely different and they can't imagine why
anyone would want to ride one. They have rather small imaginations...

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 protected] http://www.dundee.ac.uk/~pjclinch/

 

[Peter Clinch]

RonSonic wrote:

> Balance a stick on the end of your finger, a longer stick will be easier.

It will be, but if the shorter stick is easy /enough/ then it's
irrelevant. Or should everyone move to tallbikes for more visibility
and stability?

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 protected] http://www.dundee.ac.uk/~pjclinch/

 

[RonSonic]

On Wed, 21 Jun 2006 09:04:08 +0100, Peter Clinch <[email protected]>
wrote:

>RonSonic wrote:
>
>> Balance a stick on the end of your finger, a longer stick will be easier.
>
>It will be, but if the shorter stick is easy /enough/ then it's
>irrelevant. Or should everyone move to tallbikes for more visibility
>and stability?

Depends on where and how you like to ride.

Tallbikes are obviously great fun for the guys who've got them. I'm all for
people having fun on bikes.

But, like those fellows on recumbents they are mostly limited to pavement. Where
I live that's an outpost of hell. True Satan himself does not exactly own the
paved areas of Tampa, Florida, but he's got a real sweet timeshare deal. So for
me much bike fun is riding trails. Can't do much of that on either a recumbent
or a tallbike.

Then, the bottom line is: I don't think "everyone" should ride any one
particular type of bike.

Ron

 

[Peter Clinch]

RonSonic wrote:

> But, like those fellows on recumbents they are mostly limited to pavement. Where
> I live that's an outpost of hell. True Satan himself does not exactly own the
> paved areas of Tampa, Florida, but he's got a real sweet timeshare deal. So for
> me much bike fun is riding trails. Can't do much of that on either a recumbent
> or a tallbike.

Have you ever tried on a 'bent? While I don't pretend my particular
'bent is the last word for serious technical off-road, I've done plenty
of miles on it with no tarmac involved and it's basically a non-issue on
typical trails. I live next to a rough track, but I don't male a habit
of wheeling the 'bent to the door.

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 protected] http://www.dundee.ac.uk/~pjclinch/

 

[Colin]

In article <[email protected]>,
[email protected] says...

>
> No. People I've discussed this with don't like the idea of having their
> heads closer to the ground (i.e. being both unable to see as much,
> and being less visible to drivers), having less manoeuverability and
> having a larger, more cumbersome bike to store.

I read from this (correct me if I'm wrong) that the people you've
discussed this with haven't necessarily ridden a recumbent. Let's not
forget that not all recumbents are "lay horizontal, 6 inches off the
ground" bikes, in the same way not all uprights are high-wheeled
"ordinarys". My bike, a Pashley PDQ
(http://www.pashley.co.uk/pashley/products/pages/pdq_page.htm) is a
fairly "upright" recumbent, and puts me at a similar height to car
drivers, and sitting only mildly reclined. I don't find its
maneuverability to be a limiting factor, and whilst it might take up
slightly more room that a drop-handled road bike in the shed, it
nonetheless still fits in there.

>
> It's important to me to be able to see a lot on the road, be seen
> easily by everyone else and be able to hop on and off the footpath
> quickly in tight spots and thread my way between cars in queues.

I find I see more on the road on my recumbent than I did on my old road
bike, simply because my head is always up and looking ahead, without
having to lift it up from staring at the front wheel, a position that is
difficult to avoid when your backside is higher than your handlebars. As
has already been said, not only is my bike visible to everyone else, but
I often get a "double take" from people not believing their initial
glance, thus making me more visible. Personally I see no limitations in
not being able to hop on and off the footpath, because aside from being
illegal, I find I make perfectly good, and safe, progress by putting
myself where drivers expect to see traffic and riding as part of that
traffic. Suddenly appearing from the pavement tends to negate that
somewhat.

>
> ISTM that all of these would be harder on a recumbent. Can you stand
> up on it to get an even better look at the traffic ahead or put on a
> quick sprint to get out of trouble?

Certainly on my recumbent I can lean forward (and thus be more upright)
in the seat to get a better view. Granted, it won't be as high as
standing on the pedals of an upright, but it's never caused any issues
with visibility. As for putting on a quick sprint, I'd wager I can push
harder on the pedals by bracing my back against the seat than can an
upright rider before that muscle power lifts the rider from their
saddle.

At the end of the day, it's horses for courses, and if you like what you
ride, then that's great, but don't dismiss an entire range of bikes
because of the perceived limitations of a small subset.


--
Colin

Coincidence is the alibi of the Gods

 

[Dave Larrington]

In article <[email protected]>,
[email protected] says...
> In article <[email protected]>,
> [email protected] says...
>
> >
> > No. People I've discussed this with don't like the idea of having their
> > heads closer to the ground (i.e. being both unable to see as much,
> > and being less visible to drivers), having less manoeuverability and
> > having a larger, more cumbersome bike to store.
>
> I read from this (correct me if I'm wrong) that the people you've
> discussed this with haven't necessarily ridden a recumbent. Let's not
> forget that not all recumbents are "lay horizontal, 6 inches off the
> ground" bikes, in the same way not all uprights are high-wheeled
> "ordinarys". My bike, a Pashley PDQ
> (http://www.pashley.co.uk/pashley/products/pages/pdq_page.htm) is a
> fairly "upright" recumbent, and puts me at a similar height to car
> drivers, and sitting only mildly reclined. I don't find its
> maneuverability to be a limiting factor, and whilst it might take up
> slightly more room that a drop-handled road bike in the shed, it
> nonetheless still fits in there.

Wot Colin said. My Kingcycle - and I'm a long-legged 6'3" or
thereabouts - actually took up /less/ space than TWFKAML's Trek MTB.
Well, once the nosecone had disintegrated from years of abuse, anyway.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
Life - loathe it or ignore it, you can't like it.

 

[timtak]

Thanks to Jeff Potter (and Thomas David Kehoe) for this thread.

There is a lot of useful information on this thread, and postings that I agree with, so I take the liberty of rekindling the thread after a break of 4 years.

Lately I became aware of what I termed the UCI-industrial complex which seems to control cycling by presenting images of super fast pro riders riding branded bikes, that everyone is encouraged to emulate, when in fact the vast majority of non-racing cyclists could ride much faster if we ignored the pros, by using things like lowered handlebars, fairings and or recumbents that the UCI does not allow, or UCI riders do not need. It is amazing the extent to which cyclists are thrall to the lure of this UCI industrial complex straight-jacket. The tail is wagging the dog indeed. I guess there is a lot of money in it.

All I have done is lowered my bars, and I nearly bought a Zzipper but at 375 USD delivered it seemed a bit pricey, so I put a Kawasaki motorcycle windshield which cost $10 delivered, on the front of my bike. I think I can notice a difference when at top speed in my drops. I have only had it on the bike a couple of days.

I may get a Zzipper or I may bolt on some more or bigger motorcycle fairing. I am making covers for my rear wheel. I am wondering about aero-panniers. At the moment I wear a non aero backpack. I also want to make a fairing for the light on my helmet. Currently I have a light attached to the top of my helmet with cable ties.