New Shifters that Shift When You're Still

[Elisa Francesca Roselli]

I'm looking around now at some upmarket bikes for when I grow up. I will
be needing a comfort or utility style bike that can be ridden in a
skirt, carry lots of shopping, and tackle very steep hills (i.e. it
should have a fairy gear and rock-hard brakes).

Looking on the Web site of the firm Giant, I see that the new comfort
bikes for 2003-4 have a 7 speed Nexus gear shifter that advertizes that
it can be shifted even when the bike is stationary. If this works, it's
a really cool innovation, as I often find myself compromised for gear at
traffic lights or failing to make a judgement sufficiently ahead of time
to shift over several gears when terrain changes abrupty. (I live in a
roller-coaster suburb to the South of Paris.)

Does anyone have experience with these shifters? Do they really work and
are they reliable? Can one shift over several gears when standing still,
like from second to fifth, or only over one step? And is the smallest
gear on a seven-speeder a true fairy gear, or does one really need
chainwheel gears on the front wheel as well to access such mountain-bike
capacity?

Many thanks,

Elisa francesca Roselli
Ile de France

[James Thomson]

"Elisa Francesca Roselli" >
wrote:

> Looking on the Web site of the firm Giant, I see that the
> new comfort bikes for 2003-4 have a 7 speed Nexus gear
> shifter that advertizes that it can be shifted even when the
> bike is stationary. If this works, it's a really cool innovation,
> as I often find myself compromised for gear at traffic lights
> or failing to make a judgement sufficiently ahead of time to
> shift over several gears when terrain changes abrupty. (I live
> in a roller-coaster suburb to the South of Paris.)

> Does anyone have experience with these shifters? Do they
> really work and are they reliable? Can one shift over several
> gears when standing still, like from second to fifth, or only
> over one step? And is the smallest gear on a seven-speeder
> a true fairy gear, or does one really need chainwheel gears
> on the front wheel as well to access such mountain-bike
> capacity?

This is a property of epicyclic hub gears, not of the shifters used.
Sturmey Archer hubs have been shiftable when stationary since 1902. You can
select any gear you like while at a standstill - from one end of the range
to the other. The drawback is that they tend to shift less reliably under
load than modern derailleur gears, so you may need to ease off to shift
down while climbing, which can result in a loss of momentum.

Most hub gears have limits on the input torque, which are generally
expressed as a minimum ratio of chainring to sprocket - often 2:1. This can
limit the lowest gear available. Hub gears tend to have a narrower overall
range than derailleur gears, and larger gaps between ratios. Some riders
like to hybridise them with derailleurs to extend the overall range or
reduce the gaps.

To my mind, the biggest advantage of hub gears is that they require so
little maintenance whaen compared with derailleur gears.

Sheldon Brown has a number of pages on hub gears, including information on
the Nexus 7.

http://www.sheldonbrown.com/seven_speed.html

http://www.sheldonbrown.com/internal-gears.html

http://www.sheldonbrown.org/gears/internal.html

Both Shimano and Sturmey Archer are due to introduce 8-speed gears shortly.

James Thomson

[Chalo]

Elisa Francesca Roselli
> wrote:

> Looking on the Web site of the firm Giant, I see that the new comfort
> bikes for 2003-4 have a 7 speed Nexus gear shifter that advertizes that
> it can be shifted even when the bike is stationary.
....
> Does anyone have experience with these shifters? Do they really work and
> are they reliable?

Yes, they really work and are reliable. Internal-gear hubs descend
from the Sturmey Archer 3-speed, marketed at least since the early
'30s. Sturmey Archer, SRAM (formerly Sachs), Rohloff, and Shimano all
make multi-speed hubs. All of them shift as you describe.

> Can one shift over several gears when standing still,
> like from second to fifth, or only over one step?

With such a hub you can shift between opposite extremes at once if you
so choose.

> And is the smallest
> gear on a seven-speeder a true fairy gear, or does one really need
> chainwheel gears on the front wheel as well to access such mountain-bike
> capacity?

The overall (high gear:low gear) ratio varies according to
manufacturer. Shimano's 7-speed overall ratio is 2.44:1, while SRAM's
is 3.03:1. Rohloff's hub, which is offered only in 14-speed, has a
5.26:1 spread, and is the only one of them that offers true MTB
overall range.

How low your low gear is, though, is dependent on the ratio built into
your primary drive (chainring and rear sprocket). If you can stand to
sacrifice top end gears, you can have a "true fairy gear" at the low
end. I have set up my sweetheart's bike this way; using a 44/28
primary on a Sachs 5-speed hub, she has a very low bottom gear, a
modest top gear, and three in between. She'll not be breaking any
speed records with gears like that, but then that was never her
intention....

The best solution from a technical standpoint is to use the Rohloff
hub, but it costs a fortune. I find that a very good compromise is to
use a SRAM 7-speed hub set up to deliver a range of 30 to 91 gear
inches (2.4 to 7.4 meters development). In practice I find it quite
easy to live with a top gear of only 6.5 meters, which would lower the
bottom gears accordingly if you chose to do so.

The same can be done with the Shimano hub, though its smaller overall
range makes it a bit less capable in this respect.

Chalo Colina

[Ed Kirstein]

I recently got a Schwinn Voyageur GSX (USA Model). It uses the SRAM
DualDrive which gives you an 8 speed rear derailleur and a 3 speed hub. It
has all the range of a 3 gear front derailleur without the fuss of one. I'm
very impressed with it. No matter what gear I am in on the rear derailleur,
if I come to a stop, I can just shift to the lowest gear on the internal hub
and have no trouble getting going. Its a beautiful system. I notice that
Canondale also has a line of bikes using the same SRAM DualDrive system.

Ed


"Elisa Francesca Roselli" >
wrote in message ...
> I'm looking around now at some upmarket bikes for when I grow up. I will
> be needing a comfort or utility style bike that can be ridden in a
> skirt, carry lots of shopping, and tackle very steep hills (i.e. it
> should have a fairy gear and rock-hard brakes).
>
> Looking on the Web site of the firm Giant, I see that the new comfort
> bikes for 2003-4 have a 7 speed Nexus gear shifter that advertizes that
> it can be shifted even when the bike is stationary. If this works, it's
> a really cool innovation, as I often find myself compromised for gear at
> traffic lights or failing to make a judgement sufficiently ahead of time
> to shift over several gears when terrain changes abrupty. (I live in a
> roller-coaster suburb to the South of Paris.)
>
> Does anyone have experience with these shifters? Do they really work and
> are they reliable? Can one shift over several gears when standing still,
> like from second to fifth, or only over one step? And is the smallest
> gear on a seven-speeder a true fairy gear, or does one really need
> chainwheel gears on the front wheel as well to access such mountain-bike
> capacity?
>
> Many thanks,
>
> Elisa francesca Roselli
> Ile de France
>

[Elisa Francesca Roselli]

Ed Kirstein wrote:

> I recently got a Schwinn Voyageur GSX (USA Model). It uses the SRAM
> DualDrive which gives you an 8 speed rear derailleur and a 3 speed hub. It
> has all the range of a 3 gear front derailleur without the fuss of one. I'm
> very impressed with it. No matter what gear I am in on the rear derailleur,
> if I come to a stop, I can just shift to the lowest gear on the internal hub
> and have no trouble getting going. Its a beautiful system. I notice that
> Canondale also has a line of bikes using the same SRAM DualDrive system.

Do you mean a traditional derailleur on the back wheel and a 3 -speed Sturmey
Archer style shifter on the front wheel, offering a total of 24 usable speeds?
How does that work for gear-shifting? What happens with cross-shifting? Are you
saying that you can move to any of the front speeds with any of the back speeds
activated in one shift at a standstill?

It sounds very interesting. Presumably you still have to phase-shift on the back
derailleur but the modulation of the front shifter would change the "tone" of
the speed from flat to hilly even before you need to shift the back gear?

I'll look into this. The World Fair of Two-Wheelers is on in Paris this coming
weekend and you've given me a lot to ask about.

EFR
Ile de France

[Elisa Francesca Roselli]

Chalo wrote:

> The best solution from a technical standpoint is to use the Rohloff
> hub, but it costs a fortune. I find that a very good compromise is to
> use a SRAM 7-speed hub set up to deliver a range of 30 to 91 gear
> inches (2.4 to 7.4 meters development). In practice I find it quite
> easy to live with a top gear of only 6.5 meters, which would lower the
> bottom gears accordingly if you chose to do so.
>
> The same can be done with the Shimano hub, though its smaller overall
> range makes it a bit less capable in this respect.

As you probably gathered I'm much more interested in the minimum development
than in the maximum. I'm not a speed freak at all and have never felt the
impulse to exceed 35 kph even on a clean downhill run. 2.4 meters sounds
viable, although I have no idea what I currently have - gotta get round to
counting those teeth!

The way Forrester, and some of the more advanced cyclists in this forum, talk,
it sounds as though a "build your own bicycle" approach is almost feasible...
Do people here decide on their components - such and such a frame, with these
brakes, this shifter with this number of cogs each having a specific number of
teeth - and pull it together the way one could build a computer from its
individual parts? I mean, is that common or is it advanced geekery? Do you buy
a bike with most of the features you want and then diddle-and-tweak the
remaining ones? Does that come out very expensive?

Admittedly that's a whole other thread.

Elisa Francesca Roselli
Ile de France

[James Thomson]

"Elisa Francesca Roselli" >
wrote:

> Do you mean a traditional derailleur on the back wheel and a
> 3-speed Sturmey Archer style shifter on the front wheel, offering
> a total of 24 usable speeds?

It's all in the rear wheel. The rear hub is similar to a Sturmey Archer
3-speed, but carries a cluster of 7, 8 or 9 sprockets rather than a single
one. My wife has a SRAM 3x7 hub on her Moulton Landrover.

> How does that work for gear-shifting?

One control switches between the three speeds of the epicyclic gear, and
another operates the rear derailleur.

> What happens with cross-shifting? Are you saying that you can
> move to any of the front speeds with any of the back speeds
> activated in one shift at a standstill?

Any of the rear sprockets can be used with the single front chainring. The
epicyclic (3-speed) gear can be shifted into any gear when stationary.

A hybrid system like this has some of the advantages and disadvantages of
each type. The hub gear can be shifted when stopped. The derailleur shifts
well under load, has fairly small steps between gears, and allows the rider
to customize gear ratios by changing the sprockets. On the downside, the
system requires more maintenance than an epicyclic gear alone, and is
slightly less efficient in some gears that a derailleur-only system.

It's a particularly good choice for small-wheeled bikes, as the gear
multiplication in the rear hub allows normal-sized chainrings to be used
with normal-sized cassettes.

> It sounds very interesting. Presumably you still have to phase-shift
> on the back derailleur but the modulation of the front shifter would
> change the "tone" of the speed from flat to hilly even before you
> need to shift the back gear?

In terms of shifting patterns, it's much like a conventional triple
chainring set-up used with a wide range cassette. The three epicyclic gears
give three overlapping ranges. Finer tuning is done by shifting the
derailleur.

SRAM has a somewhat gimmicky web page on the Dual Drive at:
http://www.dualdrive.com

James Thomson

[David L. Johnson]

On Tue, 23 Sep 2003 11:27:18 +0200, Elisa Francesca Roselli wrote:

> The way Forrester, and some of the more advanced cyclists in this forum,
> talk, it sounds as though a "build your own bicycle" approach is almost
> feasible...

It is feasable.

> Do people here decide on their components - such and such a
> frame, with these brakes, this shifter with this number of cogs each
> having a specific number of teeth - and pull it together the way one could
> build a computer from its individual parts?

It's been a long time since I bought a complete computer, and longer since
I've bought a complete bike.

> I mean, is that common or is
> it advanced geekery?

yes....

> Do you buy a bike with most of the features you want
> and then diddle-and-tweak the remaining ones? Does that come out very
> expensive?

For me, it sort of evolves. I replace what breaks, or what I can no
longer find parts for. Usually I aim for components that are no longer
the hot thing, and pick them up cheaply at swap meets. With boutique
wheels being de rigeur for lots of folks, high-quality hubs and rims can
be had for a song.

--

David L. Johnson

__o | A foolish consistency is the hobgoblin of little minds, adored
_`\(,_ | by little statesmen and philosophers and divines. --Ralph Waldo
(_)/ (_) | Emerson

[Drew Eckhardt]

In article >,
Elisa Francesca Roselli > wrote:
>The way Forrester, and some of the more advanced cyclists in this forum, talk,
>it sounds as though a "build your own bicycle" approach is almost feasible...
>Do people here decide on their components - such and such a frame, with these
>brakes, this shifter with this number of cogs each having a specific number of
>teeth - and pull it together the way one could build a computer from its
>individual parts?

I decided exactly what I wanted based on fit + taste (30-40-50 crankset,
13-14-15-16-17-18-19-21 cogs, Campagnolo Chorus ergopower shifters,
unanodized machined rims laced with 14-15 double butted spokes, deeper drops,
favorite saddle, favorite grip tape, etc) and had a local shop build it up.

>I mean, is that common or is it advanced geekery? Do you buy
>a bike with most of the features you want and then diddle-and-tweak the
>remaining ones? Does that come out very expensive?

It didn't cost any more than a similar off-the-shelf bike did (~$2200 US
in 1995). Plus the cost of consumables (tires, chains, cogs, bar tape)
and a necessary upgrade to 9 speeds (My favorite 8-speed cassette was
discontinued), the total divided into eight years is a small fraction of
what insurance alone cost on my motor vehicles.

--
<a href="http://www.poohsticks.org/drew/">Home Page</a>
Life is a terminal sexually transmitted disease.

[Bill Davidson]

Elisa Francesca Roselli wrote:
> The way Forrester, and some of the more advanced cyclists in this forum, talk,
> it sounds as though a "build your own bicycle" approach is almost feasible...

Actually, it's quite feasible. Many of us have done it. It's sort of a natural progression
from doing maintenance, to replacing parts, to building or rebuilding. For me, it was
made easier by the fact that I had a college roommate who was a racer and already
knew how to make/fix everything on a bike and was happy to teach me. It's harder if
you don't have help.

> Do people here decide on their components - such and such a frame, with these
> brakes, this shifter with this number of cogs each having a specific number of
> teeth - and pull it together the way one could build a computer from its
> individual parts?

Yep. That's very common.

>I mean, is that common or is it advanced geekery?

Both.

> Do you buy
> a bike with most of the features you want and then diddle-and-tweak the
> remaining ones?

That happens. In my case I had a crappy bike and just replaced parts with nicer
used and sale parts on it as money allowed (I was in college). Two years later,
none of the original bike was left and I had a fairly decent racing bike.

> Does that come out very expensive?

It depends. Some parts are more expensive than others.

--Bill Davidson
--
Please remove ".nospam" from my address for email replies.

I'm a 17 year veteran of usenet -- you'd think I'd be over it by now

[Chalo]

Elisa Francesca Roselli
> wrote:

> As you probably gathered I'm much more interested in the minimum development
> than in the maximum. I'm not a speed freak at all and have never felt the
> impulse to exceed 35 kph even on a clean downhill run. 2.4 meters sounds
> viable, although I have no idea what I currently have - gotta get round to
> counting those teeth!

If you have the common MTB low gear of 22t on the crank and 28t on the
large rear sprocket, then that gives a nominal 1.63 meters
development. It is also a more difficult way to climb a hill (for
this fat guy) than to gear a little higher and pedal a little slower.
I run out of breath easily, and pedaling a lower gear faster hurts
more than it helps.

> The way Forrester, and some of the more advanced cyclists in this forum, talk,
> it sounds as though a "build your own bicycle" approach is almost feasible...

Feasible, yes; preferable, yes; but it is more expensive to buy a bike
in this way.

> Do people here decide on their components - such and such a frame, with these
> brakes, this shifter with this number of cogs each having a specific number of
> teeth - and pull it together the way one could build a computer from its
> individual parts? I mean, is that common or is it advanced geekery?

This approach is very common among bike shop employees, long-time
enthusiasts, and others who for whatever reason already have many
necessary parts at their disposal. Some such riders can also obtain
wholesale pricing, which makes the cost difference between a complete
bike and individual parts much less.

> Do you buy
> a bike with most of the features you want and then diddle-and-tweak the
> remaining ones? Does that come out very expensive?

The optimum approach for most riders is to buy a bike (at a fair
price) that most closely represents all the things that rider wants in
his or her bike. Then it is relatively simple to "trade up" and
install just those few components necessary to fit his or her
particular requirements vis-a-vis gearing, rider fit, etc. This is
most cost-effective, because the components that come equipped on a
bike often cost double that amount or more when purchased piecemeal.
The amount you pay for a complete bike is usually less than just the
cost of the individual components without the frame and fork!

Chalo Colina

[Elisa Francesca Roselli]

Chalo wrote:

> The optimum approach for most riders is to buy a bike (at a fair
> price) that most closely represents all the things that rider wants in
> his or her bike. Then it is relatively simple to "trade up" and
> install just those few components necessary to fit his or her
> particular requirements vis-a-vis gearing, rider fit, etc.

Then this too would be an argument for a "nice bike". Supermarket bikes like my
current one tend to be "non-modular", i.e. you can't easily mix and match parts.

Elisa Francesca Roselli
Ile de France