"Liquid Drive" bike prototype at auction

In rec.bicycles.misc Carl Fogel wrote:

: Is the length of the chain-run a problem? That is,
: are longer chains less efficient, harder to shift,
: more prone to wear?

Triple the cost and weight of the chain...

Many recumbents use an idler wheel or two to manage the peculiar
chain routing. I would think this eats some efficiency, maybe a
percent or two? Then again some efficiency might be regained since
the chainline from chainring to cog is relatively straight.

All in all I'd consider it a minor issue in upright-to-recumebent
comparisons.

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html
varis at no spam please iki fi

"Dave Kahn" wrote in message
... Tandem sprinting is
spectacular. See
www2.ijs.si/~mleskovar/tandem1_2.jpg

I certainly feel sorry for the stoker on the Japanese team in this photo.
Shouldn't he have a little more ... headroom?

Carl Fogel wrote:

Ryan Cousineau wrote in message ...

[massive snip]

That's just the trick. Chain is so good, it defeats all other options.
You use belts or enclosures if the filth bothers you, but that's it.
Maybe some recumbents would benefit from a long, stiff shaft drive,
given their ludicrous chain issues.


Dear Ryan,

I love ludicrous issues.

I occasionally see recumbents wobbling along on
my local bicycle path, but have never inspected
a dead one's anatomy--possibly there is a secret
recumbent graveyard.

Is the length of the chain-run a problem? That is,
are longer chains less efficient, harder to shift,
more prone to wear?

Or is it the peculiar arrangements rather than the
mere length?

Are recumbent chain problems worse than tandem chain
problems?

Any concrete answers or even wild speculation will
be appreciated, since I'd hate to shoot such rare
creatures just to dissect their chain anatomies.
I can recall only a single tandem sighting in fifteen
years and fear that they may be extinct in these parts.

J.J. Audubon

Go for a ride in or outside Victoria BC on a beautiful day. You will
see tandems flying past in their miriad colours, in harmony with the
"single" bikes of greater number.
Bring your binoculars, and your bicycle watching experience will be
enhanced. - there are birds too, if you like watching them as well.
Bernie

Tom Sherman wrote in message ...
Carl Fogel wrote:

Ryan Cousineau wrote in message ...

[massive snip]

That's just the trick. Chain is so good, it defeats all other options.
You use belts or enclosures if the filth bothers you, but that's it.
Maybe some recumbents would benefit from a long, stiff shaft drive,
given their ludicrous chain issues.

Dear Ryan,

I love ludicrous issues.

I occasionally see recumbents wobbling along on
my local bicycle path, but have never inspected
a dead one's anatomy--possibly there is a secret
recumbent graveyard.

Recumbent owners keep their bikes forever.

There are no low quality/low price recumbents (equivalent to discount
store bikes) and the majority of commercially produced recumbents were
made in the last 10 years. Therefore, unlike upright bicycles, one is
unlikely to find recumbents in dumpsters, along the curb, at police
auctions of abandoned bikes, etc.

Is the length of the chain-run a problem? That is,
are longer chains less efficient, harder to shift,
more prone to wear?

Chain wear mainly occurs when the tension (power) side of the chain is
bent around the drive cog(s). Since recumbent chains are generally much
longer, they typically last much longer (assuming similar conditions of
use). I suspect that the cost per unit distance for recumbent chains
does not differ significantly from upright chains.

Shifting quality on a recumbent depends primarily on the quality of
derailleurs, shifters, cassettes and chainrings used. An advantage of
RWD recumbents is that the chain angle is lessened when the driven cog
does not line up with the driving chainring. One can get away with using
cross-gears much more so than on an upright. On the downside, recumbent
shifter cable runs are typically longer and more convoluted than those
of uprights are, and this can impact shifting in a negative manner.

Small drivewheel bicycles that use larger than normal chainrings
generally have poorer shifting quality - this is true of both recumbents
and small wheel uprights. I had 73/52 chainrings on a bike I used to own
[1] and front shifting was not the best. This is compounded by the lack
of large chainrings with ramps and pins. My current bike uses a clever
step-up jackshaft to avoid this problem and has excellent from shifting.
[2]

Or is it the peculiar arrangements rather than the
mere length?

For reasons of aerodynamics (reduced frontal area) and power production
(angle formed by the seatback, seat base and BB) unfaired performance
recumbents have the BB located higher than the seat. A direct chain run
from the BB to the rear sprocket(s) would pass through the rider.
Therefore, some combination of mid-drive, jackshaft, chain idlers, chain
tensioners and chain tubes is required for chain routing.

Any concrete answers or even wild speculation will
be appreciated, since I'd hate to shoot such rare
creatures just to dissect their chain anatomies.
I can recall only a single tandem sighting in fifteen
years and fear that they may be extinct in these parts.

J.J. Audubon

[1] http://www.ihpva.org/incoming/2001/wbone2.jpg
[2] http://www.ihpva.org/incoming/2002/sunset/Sunset001.jpg

Tom Sherman - Planet Earth

Dear Tom,

You know how to pander to my chain fantasies.
It's so much easier to ask than to think. I'd
never thought about how a longer chain should
last longer and cross-chain with less angle
between the front and rear sprockets.

Your two pictures delight me, though perhaps
not in the way that you intended. I feel like
someone who's never seen anything but labradors
stumbling over his first basset hound. Those
(no offense intended) are some weird-looking
bikes.

The recumbents that I see in my little backwater
in Pueblo, Colorado, must be the equivalent of
the inexpensive mountain bikes sold at WalMart.
The riders sit higher, their feet are lower, the
wheels are larger, and the chain runs seem much
more straightforward than that Rube Goldberg
contraption in your second--I mean your beloved
current bike, the one in your second picture.

If you'll pardon a somewhat personal question,
do the chains on the more complicated bike give
any trouble in terms of staying on? That is, do
you need some recumbent-specific chain-watchers
to tame the unruly beasts beyond the guide-wheels?

Thanks for a marvelous answer,

Carl Fogel

Carl Fogel wrote:
...
The recumbents that I see in my little backwater
in Pueblo, Colorado, must be the equivalent of
the inexpensive mountain bikes sold at WalMart.
The riders sit higher, their feet are lower, the
wheels are larger, and the chain runs seem much
more straightforward than that Rube Goldberg
contraption in your second--I mean your beloved
current bike, the one in your second picture.

This bike fits your verbal description.
http://www.easyracers.com/gold_rush.htm
It is one of the classic recumbent designs, but is hardly "x-Mart" in
quality or price (you can get a rather nice road bike for $3000 US).

Both my former and current bike are rare and unusual by even recumbent
standards - however they provide a good illustration of chain management
issues.

If you'll pardon a somewhat personal question,
do the chains on the more complicated bike give
any trouble in terms of staying on? That is, do
you need some recumbent-specific chain-watchers
to tame the unruly beasts beyond the guide-wheels?

The Wishbone (nickel-plated bike) had the worse chain management, as the
chain would fall off the idlers at a distressing frequency. This could
have been cured by a different idler design that included a "chain dog"
which is a pin or plate that forces the chain to stay in the idler
groove. Most regular production recumbents have these (this bike was
more of a prototype).

On the Sunset (red bike) the chain(s) can fall off the jackshaft cogs
http://www.ihpva.org/incoming/2002/sunset/Sunset005.jpg although that
is a rare occurrence. This is the one weak point in the bike's design as
far as I am concerned, and something I plan to have corrected at some
point.

Thanks for a marvelous answer,

You are welcome.

Tom Sherman - Planet Earth

Why are tandems more popular in some places while not in others?

This year I've spotted 2 recumbents, 3 upright trikes, 1 folding
bike in the wild (only counting sightings in Finland). Don't
recall seeing a tandem ever.

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html
varis at no spam please iki fi

In rec.bicycles.misc Carl Fogel wrote:

: The recumbents that I see in my little backwater
: in Pueblo, Colorado, must be the equivalent of
: the inexpensive mountain bikes sold at WalMart.
: The riders sit higher, their feet are lower, the
: wheels are larger, and the chain runs seem much
: more straightforward than that Rube Goldberg

Not necessarily, they sound more like touring bents by your
description. Go read some recumbent websites (there's plenty) for
info on all the designs out there :-)

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html
varis at no spam please iki fi

(Carl Fogel) wrote in message . com...

You know how to pander to my chain fantasies.
It's so much easier to ask than to think. I'd
never thought about how a longer chain should
last longer and cross-chain with less angle
between the front and rear sprockets.

Your two pictures delight me, though perhaps
not in the way that you intended. I feel like
someone who's never seen anything but labradors
stumbling over his first basset hound. Those
(no offense intended) are some weird-looking
bikes.

The recumbents that I see in my little backwater
in Pueblo, Colorado, must be the equivalent of
the inexpensive mountain bikes sold at WalMart.
The riders sit higher, their feet are lower, the
wheels are larger, and the chain runs seem much
more straightforward than that Rube Goldberg
contraption in your second--I mean your beloved
current bike, the one in your second picture.

If you'll pardon a somewhat personal question,
do the chains on the more complicated bike give
any trouble in terms of staying on? That is, do
you need some recumbent-specific chain-watchers
to tame the unruly beasts beyond the guide-wheels?

Thanks for a marvelous answer,

Carl, I'll entertain you with a few more pics.

http://www.biketcba.org/TRICORR/vrex2.jpg
http://www.biketcba.org/TRICORR/mgruizenga.jpg

The first one is of my slightly customized V-Rex. It has a pretty
straight chainline, with only one power side idler to prevent too much
chain slap. It's never come off, although it once jumped the return
idler by the fork. It has an ISO 507 (24") rear wheel and an ISO 451
(20") front wheel. This model is considered a 'sport' model, and it's
the equivalent to a mid-level road bike. Both of Tom's bikes would be
considered 'faster' bikes. The 30/44/56 chainrings shift a little
balkily, but as Tom wrote, larger rings do that; and it spends most of
its time in the big ring anyway. OBTW it takes about two and a half
chains , which seem to last about 10,000 miles.

By far the most common recumbent model in my club is the TourEasy. The
second pic is of one of the club members on his aluminum-framed model.
These bikes have the rider sitting more upright, but they are made to
be used in conjunction with the fairing you see. Keeping the rider
relatively close to the fairing helps aerodynamics, so the bike you
see is not slow. In fact, the speed demons of the club put body socks
on the bikes, in effect making lycra-bodied streamliners. They ride
with the 'A' riders in a swarm, like jet fighters protecting a bomber
squadron. The smell-the-roses riders like this model too, because the
low pedals make it easy to ride; so if you see one going slow,
consider the engine. TourEasys have no power side idlers, so chain
deflection, even in the extreme gears, is almost unnoticeable.

To relate back to the original subject, I for one would rather
continue to deal with chain routing than to lose efficiency or gain
too much extra weight with a hydraulic drive system.

wrote in message
...
Why are tandems more popular in some places while not in others?

This year I've spotted 2 recumbents, 3 upright trikes, 1 folding
bike in the wild (only counting sightings in Finland). Don't
recall seeing a tandem ever.

Darned if I know.
But I do know that the best bad-winter-weather tires seem to be made in
Finland (Nokians), and that tandems are, in general, a fair-weather bike.
Maybe there's the connection.

Tom Sherman wrote in message ...

On the Sunset (red bike) the chain(s) can fall off the jackshaft cogs
http://www.ihpva.org/incoming/2002/sunset/Sunset005.jpg although that
is a rare occurrence. This is the one weak point in the bike's design as
far as I am concerned, and something I plan to have corrected at some
point.

The rear chain on my Sunset falls off to the inside of the jackshaft
cog almost every time I coast on a rough, high speed descent while in
the smallest rear cassette cog. This is due to a combination of the
chain line and having the lowest chain tension when in the smallest
cog. I'm using a Dura-Ace short cage rear derailer. So once I stop
pedalling on a descent (usually 50-60 km/h range) I shift to a larger
cog towards the middle of the cassette and coast. When I want to pedal
again I start pedalling and simultaneously shift to the smallest rear
cog. The real solution is to put chain guard discs to each side of the
jackshaft cogs.

Interestingly when the chain falls off the jackshaft cog it sits on a
collar next to the cog and I'm able to reach down with my right hand
and put the chain back on the cog. I've done this at speed several
times, in fact twice on one descent last weekend when I was riding
with a tandem. I told them I lost the engine as I reached down and put
it back on the cog. I don't like taking a hand off the handlebars on a
rough descent though and it gets my glove dirty.

Normally for a hilly club ride I'd be riding my Bacchetta Aero which
has much better chain management along with lower weight, less rolling
resistance, superior aerodynamics, a smoother ride and a higher seat
height which makes it easier to talk with riders on conventional bikes
and also more traffic friendly on roads with poor sight lines and/or
lots of SUV's. I wasn't riding the Aero on the ride last weekend as it
wasn't one of the faster paced rides and I wanted to get a reasonable
workout plus I was expecting some wet roads and my Sunset has
mudguards while on the Aero there really isn't provisions for mounting
them, at least on the low clearance carbon fibre road bike fork. You
can see the Aero at www.bacchettabikes.com.

Zach Kaplan