Shaft Drive Bikes

Tosspot said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

I'm kind of intrigued by the idea of shaft drive bikes but as I
understand it, shaft drive is quite a bit less efficient that chain
drive. I have a feeling the two might be on par for tadpole and LWB
recumbents though.

Chris
--
Chris Eilbeck

Tosspot wrote on 08/12/2006 18:25 +0100:

Quoted message said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

No. AUSHTA http://sheldonbrown.com/gloss_sa-o.html

"Shaft drive
An alternative drive system, replacing the chain and sprockets with
right-angle bevel gears and a shaft running inside the right hand
"chainstay."

Shaft drive was briefly popular around 1900, and occasional
attempts are made to revive the design. Unfortunately, shaft drive turns
out to have more problems than advantages.

A shaft drive requres heavier frame construction around the bevel
gears to maintain their precise alignment under load. The drive system
is heavier and less efficient than a good chain drive.

For reasons of clearance, the bevel gears of a shaft drive bicycle
must be considerably smaller than the typical sprockets used with a
chain drive. The smaller size of the gears causes an increase in the
stresses on the whole support system for the shaft. This problem is
exacerbated by the fact that the stresses from the shaft drive are not
well resisted by the triangulated structure of a bicycle frame, because
the stresses are perpendicular to the triangle.

Most of the advantages touted by proponents of shaft drive are only
advantages compared with open-chain, derailer gear systems. Many
proponents of shaft drive use specious (if not dishonest) arguments
"comparing" shaft drive systems with derailer gear systems. Any such
comparisons are meaningless, it's like comparing apples and locomotives.

A valid comparison of shaft vs. chain drives can only be made if
both bikes use the same type of gearing, whether singles-speed or with
an internal gear system.

These same advantages can be obtained with chain drive using a
fully-enclosing chain case, as with old English roadsters and many
current Dutch bikes.

Shaft drive proponents also often compare sealed, enclosed shaft
drive systems with open, exposed chain drive systems. This is also a
misleading comparison. All of the advantages claimed for shaft drive can
be realized by the use of a chain case."

--
Tony

"...has many omissions and contains much that is apocryphal, or at least
wildly inaccurate..."
Douglas Adams; The Hitchhiker's Guide to the Galaxy

in message <[email hidden]>, Tosspot

(') said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

Benefits: clean.

Disbenefits: less good efficiency, mechanically fragile, difficult to
change rear tyre.

A monoblade rear end with a properly engineered prop shaft would get around
the fragility and tyre problems, but then a monoblade rear end with a
properly designed enclosed chain with oil bath would also solve both of
those without the efficiency penalty. On the other hand a monoblade which
encloses a chain is necessarily something of a plank, and is not going to
look visually appealing; a monoblade which has only to incorporate a shaft
can be smaller and less visually obtrusive. In either case the sensible
place to put the variable ratio mechanism is at the pedal end of the
transmission, for weight distribution reasons.

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

See one nuclear war, you've seen them all.

Quoted message said:

I'm kind of intrigued by the idea of shaft drive bikes but as I
understand it, shaft drive is quite a bit less efficient that chain
drive. I have a feeling the two might be on par for tadpole and LWB
recumbents though.

The website quotes 94% Vs 97% for a well maintained chain-driven bike.

I'd prolly buy one if I was in the market for a good commuter, but I'd
definately only buy after a long test ride where I really put the bike
through its paces. I'd also compare it to the shops similarly specced
regular bikes too - not sure if that drop in efficiency would be enough to
annoy at higher speeds.

Simon Brooke said:

A monoblade rear end with a properly engineered prop shaft would get
around the fragility and tyre problems, but then a monoblade rear end
with a properly designed enclosed chain with oil bath would also solve
both of those without the efficiency penalty. On the other hand a
monoblade which encloses a chain is necessarily something of a plank,
and is not going to look visually appealing; a monoblade which has
only to incorporate a shaft can be smaller and less visually
obtrusive.

Well, the Green machine does not look too bad:
<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Quoted message said:

In either case the sensible place to put the variable ratio
mechanism is at the pedal end of the transmission, for weight
distribution reasons.

In this specific case it might put too much weight on the front end :-)

Günther

Tosspot said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

Ok, my tuppence worth. No. You can't change the gearing by simple
replacement of the rear cog/chain ring. Next, it's a custom frame, not
suited to anything else.

Otoh, it's bling, and clean bling at that. But better than an enclosed
chain? No, I don't reckon so.

Chris Eilbeck said:

I'm kind of intrigued by the idea of shaft drive bikes but as I
understand it, shaft drive is quite a bit less efficient that chain
drive.

Shaft drive itself is fine - the trick is to wrap it in a torque tube
carrier and to use that as the reaction member. With moderately modern
materials, this works fine and doesn't require anymore from the frame.

Gearing is still awkward. Straight bevels are ugly, hypoid are still a
little less efficient than a chain. However we now have cheap moulded
self-lubricating hypoids that are almost as good. If not as good as a
clean well-maintained chain, they're certainly as good as some nasty
old Clifton suspension bridge of a chain with a hooked chainring.

I don't think shaft drive will replace desirable bikes. But it
certainly has a niche opening up as the zero-input commuter.

Chris Eilbeck said:

I'm kind of intrigued by the idea of shaft drive bikes but as I
understand it, shaft drive is quite a bit less efficient that chain
drive.

Shaft drive itself is fine - the trick is to wrap it in a torque tube
carrier and to use that as the reaction member. With moderately modern
materials, this works fine and doesn't require anymore from the frame.

Gearing is still awkward. Straight bevels are ugly, hypoid are still a
little less efficient than a chain. However we now have cheap moulded
self-lubricating hypoids that are almost as good. If not as good as a
clean well-maintained chain, they're certainly as good as some nasty
old Clifton suspension bridge of a chain with a hooked chainring.

I don't think shaft drive will replace desirable bikes. But it
certainly has a niche opening up as the zero-input commuter.

Chris Eilbeck said:

I'm kind of intrigued by the idea of shaft drive bikes but as I
understand it, shaft drive is quite a bit less efficient that chain
drive.

Shaft drive itself is fine - the trick is to wrap it in a torque tube
carrier and to use that as the reaction member. With moderately modern
materials, this works fine and doesn't require anymore from the frame.

Gearing is still awkward. Straight bevels are ugly, hypoid are still a
little less efficient than a chain. However we now have cheap moulded
self-lubricating hypoids that are almost as good. If not as good as a
clean well-maintained chain, they're certainly as good as some nasty
old Clifton suspension bridge of a chain with a hooked chainring.

I don't think shaft drive will replace desirable bikes. But it
certainly has a niche opening up as the zero-input commuter.

in message <[email hidden]>, Günther Schwarz

(') said:

Simon Brooke said:

A monoblade rear end with a properly engineered prop shaft would get
around the fragility and tyre problems, but then a monoblade rear end
with a properly designed enclosed chain with oil bath would also solve
both of those without the efficiency penalty. On the other hand a
monoblade which encloses a chain is necessarily something of a plank,
and is not going to look visually appealing; a monoblade which has
only to incorporate a shaft can be smaller and less visually
obtrusive.

Well, the Green machine does not look too bad:

<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Now that ticks so many of my boxes about how a bike for the twenty-first
century ought to be designed! Fully enclosed drivetrain, gearbox near the
centre of gravity, monoblades both ends... Excellent, congratulations to
Flevobike. It's bit heavy, although that probably isn't a problem in its
home market. Any idea what this will cost? What are the hubs like? Can you
remove the wheels from the bike leaving the hubs and brakes on, and if so
are the wheels themselves identical and interchangeable?

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

;; Semper in faecibus sumus, sole profundum variat.

Tosspot said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

see Velovision Issue 23 for one purchaser's review of a Zero - he likes
it

Simon Brooke said:

in message <[email hidden]>, Günther Schwarz
([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

Well, the Green machine does not look too bad:

<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Quoted message said:

Now that ticks so many of my boxes about how a bike for the
twenty-first century ought to be designed! Fully enclosed drivetrain,
gearbox near the centre of gravity, monoblades both ends... Excellent,
congratulations to Flevobike. It's bit heavy, although that probably
isn't a problem in its home market.

At 15,5 kg without fenders and such it is not really light but also not
heavy.

Quoted message said:

Any idea what this will cost?

Tempelman sells them for 3420,-, which is not excessive if compared to
other SWB recumbents with a Rohloff hub.

Quoted message said:

What
are the hubs like? Can you remove the wheels from the bike leaving the
hubs and brakes on, and if so are the wheels themselves identical and
interchangeable?

I don't know as I did not have to occasion to test one yet. But as long
as one does not want to carry a spare wheel I can see no benefits in
this. The possible benefits of the rear swingarm for diamond framed
bicycles are obvious.

Günther

Günther Schwarz wrote on 08/12/2006 23:13 +0100:

Quoted message said:

Well, the Green machine does not look too bad:
<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

But is chain, not shaft, drive:
"The closed “Box” construction keeps all water, mud, debris and brine
out and fully protects the chain drive train"

--
Tony

"...has many omissions and contains much that is apocryphal, or at least
wildly inaccurate..."
Douglas Adams; The Hitchhiker's Guide to the Galaxy

Tony Raven said:

Günther Schwarz wrote on 08/12/2006 23:13 +0100:

Quoted message said:

Well, the Green machine does not look too bad:

Quoted message said:

But is chain, not shaft, drive:
"The closed ?Box? construction keeps all water, mud, debris and brine
out and fully protects the chain drive train"

Yes, shure. You did cut off the part of Simon's posting to which I
replied:

| On the other hand a monoblade which encloses a chain is necessarily
| something of a plank, and is not going to look visually appealing

As others have already pointed out a single 'chainstay' enclosing a
shaft drive like e.g. found on BMW motorcycles will not likely being
smaller or lighter than the arm of the Green Machine.

Günther

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

Quoted message said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

Nearly $1200 .. including $299 shipping to Europe? Halfords is cheaper....

in message <[email hidden]>, Tony Raven

(') said:

Günther Schwarz wrote on 08/12/2006 23:13 +0100:

Quoted message said:

Well, the Green machine does not look too bad:

<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Quoted message said:

But is chain, not shaft, drive:
"The closed “Box” construction keeps all water, mud, debris and brine
out and fully protects the chain drive train"

But seeing we're all agreed that an enclosed chain is better than a shaft,
how is this a problem?

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

Do not sail on uphill water.
- Bill Lee

in message <[email hidden]>, Günther Schwarz

(') said:

Simon Brooke said:

in message <[email hidden]>, Günther Schwarz
([email hidden]'😉 wrote:

Quoted message said:

Quoted message said:

Well, the Green machine does not look too bad:

<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Quoted message said:

Quoted message said:

Now that ticks so many of my boxes about how a bike for the
twenty-first century ought to be designed! Fully enclosed drivetrain,
gearbox near the centre of gravity, monoblades both ends... Excellent,
congratulations to Flevobike. It's bit heavy, although that probably
isn't a problem in its home market.

At 15,5 kg without fenders and such it is not really light but also not
heavy.

Competitive with conventional recumbents of similar geometry, certainly.

Quoted message said:

Quoted message said:

Any idea what this will cost?

Tempelman sells them for 3420,-, which is not excessive if compared to
other SWB recumbents with a Rohloff hub.

About UKP 2,300, then. No, not excessive, given the apparent quality and
the Rohloff.

Quoted message said:

Quoted message said:

What
are the hubs like? Can you remove the wheels from the bike leaving the
hubs and brakes on, and if so are the wheels themselves identical and
interchangeable?

I don't know as I did not have to occasion to test one yet. But as long
as one does not want to carry a spare wheel I can see no benefits in
this. The possible benefits of the rear swingarm for diamond framed
bicycles are obvious.

Absolutely. The reason I'm thinking about interchangeable wheel systems is
for racing, because it reduces the number of spare wheels one would have
to carry; if not racing, of course, no special benefit.

It's a very interesting bike.

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

;; I can't work yanks out......
;; Why do they frown upon sex yet relish violence?
;; Deep Fried Lettuce

Simon Brooke said:

in message <[email hidden]>, Günther Schwarz

(') said:

Simon Brooke said:

in message <[email hidden]>, Günther Schwarz
([email hidden]'😉 wrote:

Quoted message said:

> Well, the Green machine does not look too bad:

<http://www.flevobike.nl/images/stories/producten/greenmachine/600px/gm-zijaanzicht06.jpg>

Quoted message said:

Quoted message said:

Quoted message said:

What
are the hubs like? Can you remove the wheels from the bike leaving
the hubs and brakes on, and if so are the wheels themselves
identical and interchangeable?

I don't know as I did not have to occasion to test one yet. But as
long as one does not want to carry a spare wheel I can see no
benefits in this. The possible benefits of the rear swingarm for
diamond framed bicycles are obvious.

Absolutely. The reason I'm thinking about interchangeable wheel
systems is for racing, because it reduces the number of spare wheels
one would have to carry; if not racing, of course, no special benefit.

Well, taking one or two bags with spare wheels to a racing event does
not really make a difference. The more interesting question regarding
the wheels of this bike is whether the fork will accept the new Schmidt
hub for trikes. A low maintenance commuter bike without lights might be
considered as kind of strange.

Günther

ian henden said:

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

Quoted message said:

Shamelessly stolen from r.b.t and a Google

http://www.dynamicbicycles.com/

Would you buy one? If so why? If not why?

Nearly $1200 .. including $299 shipping to Europe? Halfords is cheaper....

Muji used to sell one for less than that, but I can't see it on their
website.

I recall visiting a guy in Lowestoft, about 30 years ago, who had built
a hydraulic transmission bicycle. I have no idea what the efficiency
would be, but it allows the possibility of continuously variable gears.
(Granted that doesn't sound like much of an advantage, but it avoids those
jarring changes when you're unexpectedly presented with a steep hill.)
Hmm, if you had a continuously variable hydraulic transmission, would it
work 'in reverse' like a fixed wheel bicycle and allow you to lose
speed in any gear by pedal pressure? That would be nice!

How about avoiding the torque and friction problems of a shaft drive by
using conrods to transmit power to the rear wheel? Ball bearings and
twin conrods so that the driven side is always in tension. The axle
would need to rotate and drive the rear wheel via a hub gear. It's bound to
have been invented in the 19th century!

--
Jan