or Connect
Cycling Forums › Forums › Bikes › Cycling Equipment › Shaft Drive Bikes
New Posts  All Forums:Forum Nav:

Shaft Drive Bikes

post #1 of 14
Thread Starter 
What is the prevailing opinon of shaft drive for bicycles? I was
looking at one of the ads here on google for shaft drive bicycles and
the concept looks intreguing. Espcially for a commuter bike.
post #2 of 14

Re: Shaft Drive Bikes

On 1 Aug 2006 11:12:19 -0700, "Cobben Sence" <jlucci@houston.rr.com>
wrote:

>What is the prevailing opinon of shaft drive for bicycles? I was
>looking at one of the ads here on google for shaft drive bicycles and
>the concept looks intreguing. Espcially for a commuter bike.


Dear Common,

A shaft drive avoids an oily chain, but no other advantages come to
mind.

They were first tried over a century ago.

Examples of shaft drive bicycles are usually mechanically elegant, but
pointless from a practical point of view.

Shaft drives are heavier, harder to manufacture, and less efficient at
transmitting power than chains. Providing more than one gear is
tricky.

For truly prevailing views, simply count the number of shaft drive
bicycles that you see on the road and compare that to the number of
chain drive bicycles.

Street motorcycles don't mind the extra weight or power loss, and
they're already doing much trickier things with gearboxes and
manufacture than anything with pedals, so shaft drives do hold a fair
amount of the market for gasoline-powered bicycles.

Cheers,

Carl Fogel
post #3 of 14

Re: Shaft Drive Bikes

Cobben Sence wrote:
> What is the prevailing opinon of shaft drive for bicycles? I was
> looking at one of the ads here on google for shaft drive bicycles and
> the concept looks intreguing. Espcially for a commuter bike.


I wish it were as cool as it sounds on paper, but currently chains are
the way to go. Chains are very efficient and the status quo, good luck
finding parts if your shaft breaks.

The best balance is found with a bike that has an internally geared
hub, with a nickel plated heavy duty chain to drive it. Such a chain
can be lightly lubed once per month or so with the exterior wiped
completely dry--or you can just replace it when it gets unbearably
noisy.
post #4 of 14

Re: Shaft Drive Bikes

Werehatrack wrote:
> A pair of right-angle gear drives are inherently less mechanically
> efficient than a chain drive, and are much more costly to make. Shaft
> drives preclude the use of an inexpensive derailleur system for gear
> ratio variation on demand. Is it any wonder, then, that shaft drive,
> despite having been around for at least a century, is a rare system?


The Taiwanese say you got it all backwards:

http://www.sussex.com.tw/se5-1.htm

The real problem seems to be sheer mass. Ergo, "one of the
lightest chainless bikes on the market" tips in at 27 lbs:

http://www.dynamicbicycles.com/pdf/Sprint.pdf

--Blair
post #5 of 14

Re: Shaft Drive Bikes

On 1 Aug 2006 11:12:19 -0700, "Cobben Sence" <jlucci@houston.rr.com>
wrote:

>What is the prevailing opinon of shaft drive for bicycles? I was
>looking at one of the ads here on google for shaft drive bicycles and
>the concept looks intreguing. Espcially for a commuter bike.


Dear Common,

Here are some current shaft-drive bicycles:

http://www.niagarabicycles.com/bikes.html

You can buy the first bike ($739 Canadian) for the cost of renting it
for three weeks (21 x $35/day = $735 Canadian).

It gets around the gearing problem with a 7-speed Nexus hub.

The mathematically improbable "17-gear range" may mean that the high
and low gears are as wide apart as 17 gears on some derailleur system.

Models with a Nexus 8-speed hub claim a "20-gear range."

Internal hub gears and shaft drive tend to be heavy, which may be why
the otherwise detailed specifications that give even the stem angle in
degrees coyly fail to mention weight.

The shyness may be paranoid. The weight increases may be trivial in
terms of practical bicycling. When a hub with internal gears replaces
a derailleur system, the weight increase of a pound or two really
doesn't matter much for ordinary pavement riding.

Still, it looks like the chief advantage of the shaft drive is that
people might pay $35 per day ($25 for a half day, $18 for the minimum
2 hours) to rent an odd bicycle.

Cheers,

Carl Fogel
post #6 of 14

Re: Shaft Drive Bikes

On 2 Aug 2006 22:30:34 -0700, "Blair P. Houghton"
<blair.houghton@gmail.com> wrote:

>
>Werehatrack wrote:
>> A pair of right-angle gear drives are inherently less mechanically
>> efficient than a chain drive, and are much more costly to make. Shaft
>> drives preclude the use of an inexpensive derailleur system for gear
>> ratio variation on demand. Is it any wonder, then, that shaft drive,
>> despite having been around for at least a century, is a rare system?

>
>The Taiwanese say you got it all backwards:
>
>http://www.sussex.com.tw/se5-1.htm
>
>The real problem seems to be sheer mass. Ergo, "one of the
>lightest chainless bikes on the market" tips in at 27 lbs:
>
>http://www.dynamicbicycles.com/pdf/Sprint.pdf
>
>--Blair


Dear Blair,

Yes, that Taiwanese site does claim that its shaft and internal hub
transmission is more efficient than a chain drive.

But the claim is simply not true.

They claim a 1% transmission loss for a shaft drive connected to an
internal hub, while chains lose 2% "under special conditions."

Here's a test of just the loss when a chain is connected not to a
cassette but a variety of internal hubs:

http://www.ihpva.org/pubs/HP52.pdf

Kyle and Berto's testing showed that a 3x9 derailleur Shimano Ultegra
averaged 93% efficiency (see figure 11).

Four hub gear systems from Sachs, Shimano, and Sturmey averaged 88% to
92% (see figure 12).

The Browning 4 did better than the normal derailleur, but it and the
poorly performing Browning 12 speeds are weird derailleur-type
designs.

Replacing the chain with a shaft drive would only make the internal
hubs even less efficient.

Cheers,

Carl Fogel
post #7 of 14

Re: Shaft Drive Bikes

carlfogel@comcast.net wrote:
> Replacing the chain with a shaft drive would only make the internal
> hubs even less efficient.


What in the data you linked leads you to claim that?

There's a name for that fallacy.

--Blair
post #8 of 14

Re: Shaft Drive Bikes

carlfogel@comcast.net wrote:
> Still, it looks like the chief advantage of the shaft drive is that
> people might pay $35 per day ($25 for a half day, $18 for the minimum
> 2 hours) to rent an odd bicycle.


I'd want one to have a sealed drive train in muddy conditions.

Or to keep the grease off my pants, if I was commuting.

Or to increase my athletic ability by lugging an extra ten
pounds of bike around everywhere I go...

--Blair
post #9 of 14

Re: Shaft Drive Bikes

On 2 Aug 2006 23:08:59 -0700, "Blair P. Houghton"
<blair.houghton@gmail.com> wrote:

>
>carlfogel@comcast.net wrote:
>> Replacing the chain with a shaft drive would only make the internal
>> hubs even less efficient.

>
>What in the data you linked leads you to claim that?
>
>There's a name for that fallacy.
>
>--Blair


Dear Blair,

You're right. I skipped a step.

I should have added that in typical motorcycle primary transmissions,
dynometer testing showed long ago that chains lose about 3% of the
engine power, while gears lose about 5%.

Or quoted something familiar to gear-vs-chain debates, like this Wiki
entry:

"Shaft-driven bikes have a large bevel gear where a conventional bike
would have its chainring. This would mesh to another bevel gear
mounted on the driveshaft. The use of bevel gears allows drive from
the pedals to be turned through 90 degrees. The driveshaft then has
another bevel gear near the rear wheel hub which mesh to a bevel gear
on the hub where the rear sprocket would be on a conventional bike.
The 90-degree change of plane, for the drive, that occurs at the
bottom bracket and again at the rear hub requires the use of bevel
gears. Bevel gears are notorious for their lack of efficiency as much
power is lost to friction. However, bevel gears are more efficient
than the alternative methods of turning drive through 90 degrees, like
worm gears or crossed helical gears."

http://en.wikipedia.org/wiki/Shaft-driven_bicycle

Two pairs of gears at 90 degrees are just not efficient compared to
chains running in line.

With that in mind, the argument a fortiori ensues:

Replacing a chain with 2 pairs of inefficient bevel gears and then
running the power through another set of bevel gears in a hub will
decrease efficiency.

Cheers,

Carl Fogel
post #10 of 14

Re: Shaft Drive Bikes

Sheldon Brown wrote:
> 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.


Isn't that last paragraph redundant with the previous three?

I'd keep the last one. It's simpler and doesn't belabor the lack of
examples.

--Blair
post #11 of 14

Re: Shaft Drive Bikes


> Sheldon Brown wrote:


>> 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.


except looks, which is soooo important in some circles
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl
post #12 of 14

Re: Shaft Drive Bikes

In article <44D23904.3020301@sheldonbrown.com>,
Sheldon Brown <captbike@sheldonbrown.com> wrote:


>

snip

> 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.
> ------------------------------------------------
>
> http://sheldonbrown.com/gloss_sa-o.html#shaft
>
> Sheldon "An Idea Whose Time Has Gone" Brown
> +-------------------------------------------+
> | If Stupidity got us into this mess, |
> | then why can't it get us out? |
> | -- Will Rogers |
> +-------------------------------------------+
> Harris Cyclery, West Newton, Massachusetts
> Phone 617-244-9772 FAX 617-244-1041
> http://harriscyclery.com
> Hard-to-find parts shipped Worldwide
> http://captainbike.com http://sheldonbrown.com


It appears that you and Will Rogers have explained why shaft drive will
make a "comeback" as the latest and greatest!

Along with 16 geared internal hubs.....

HAND

Hope your foot/leg problem has been healed.
post #13 of 14

Re: Shaft Drive Bikes

Yes, they are cool. A real eye catcher. Bikers always want to look at
it. Unlike all the other "experts" that have replied, I bought one!
Got a Newport Incline 3 speed model on ebay a couple of years ago for a
great price. The intended use was a all season commuter for my wife
and this bike fits that purpose better than any other. Upright riding
position for city use. No chain to bother with. Aluminum frame, power
coated. All components are aluminum, stainless steel, rubber or
plastic. Nothing to rust. Okay after 2 years, we found the two screws
that hold the rear plastic bevel gear cover rusty. My wife is a slow
twitch fiber sort of rider so I have no concerns about her over
torquing the drive shaft or gears.

complaints? it's geared to high. My wife's commute includes a bit of
a hill and her primary complaint was low gear wasn't low enough. The
drive shaft kit from Sun has a fixed reduction ratio (2:1?) and you
can't change that. Similar to a 42/21 drive. Looking at the gearing
on the other hub options shows the lowest gear ratio on the Sturmey
Archer 3 speed hub is similar to the lowest gear on the Nexus 4 & 7
speed hubs. More gears seems to mean closer spacing in ratios, not
lower gears.

Complaint 2. No reply from my repeated emails to SUN/Sturmey Archer of
USA. Maybe someone can knock on the doors next time they pass thru
Napa , CA to see if there is anyone inside.

The drive shaft is offered as a oem kit to bike manufacturers by Sun of
Tawian. That's the company that bought the remains of Sturmey Archer a
few years ago. I've seen quite a few different models and brands
offering the drive shaft. And with 3, 4, or 7 speed hubs. Many of the
bikes are priced high. I've seen some listed over $1,200.

to answer 1 question in advance, no you can't retro fit it to an
existing bike. It has to be put on a frame built just for it. I
suppose you could go to a custom frame builder.

The reality of the weight issue is no manufacture has put one on a
light weight bike yet so the bike is heavy. I guess I could lighten
this bike 5-10 pounds by changing out several components. It came with
a shock seat post, thickly padded and coil sprung seat, steel handle
bars, steel adjustable stem, fat heavy tires, wide boxy aluminum rims.
The frame is aluminum but is big tubed and certainly not a thin wall
tubing.

Someone did the math and figured a human can put more torque on the
drive shaft than a car puts on it's drive shaft. Looking at how
slender the shaft is and how small the gears are I can certainly see
the concern. Two years and it's running fine.
Humm, my body weight all on 1 pedal via a 7 inch crank arm. 150 X 7/12
= 87 foot pounds. That is more than my first VW bug could put out.

Would I pay more than $300 for one? No. Would I buy another? No.
Best use for this bike is a all season commuter in a relatively flat
city.

Rick


Cobben Sence wrote:
> What is the prevailing opinon of shaft drive for bicycles? I was
> looking at one of the ads here on google for shaft drive bicycles and
> the concept looks intreguing. Espcially for a commuter bike.
post #14 of 14

Re: Shaft Drive Bikes

1: the price. i got a great deal on the one I bought. MSRP is way
high for what you get on all the current models.

2: the nagging worry that If I pedal too hard, it will break. And be
unrepairable since my attempts at contacting SUN have all gone
unanswered.

3: I rarely have to ride in poor weather. I just don't need an all
weather bike anymore.

I would suggest the bike for an all weather commuter if you are easy on
bikes and don't have any serious hills.

Rick


Andrew Price wrote:
> On 4 Aug 2006 15:00:04 -0700, "rick-paulos@uiowa.edu"
> <rick-paulos@uiowa.edu> wrote:
>
> [---]
>
> >Would I buy another? No.

>
> Why not?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Cycling Equipment
Cycling Forums › Forums › Bikes › Cycling Equipment › Shaft Drive Bikes