New Shifters that Shift When You're Still

Elisa Francesca Roselli said:

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.)

Quoted message said:

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.

sheldonbrown.comseven speed.htmlOpen ↗

sheldonbrown.cominternal gears.htmlOpen ↗

sheldonbrown.orginternal.htmlOpen ↗

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

James Thomson

Elisa Francesca Roselli said:

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.

...

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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

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

Quoted message said:

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

Ed Kirstein said:

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

Chalo said:

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

Elisa Francesca Roselli said:

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.

Quoted message said:

How does that work for gear-shifting?

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

Quoted message said:

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.

Quoted message said:

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: dualdrive.comdualdrive.comOpen ↗

James Thomson

Elisa Francesca Roselli said:

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.

Quoted message said:

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.

Quoted message said:

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

yes....

Quoted message said:

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

In article <[email hidden]>, Elisa Francesca Roselli

Quoted message said:

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.

Quoted message said:

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="poohsticks.orgdrewOpen ↗">Home Page</a

Elisa Francesca Roselli said:

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.

Quoted message said:

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.

Quoted message said:

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

Both.

Quoted message said:

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.

Quoted message said:

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

Elisa Francesca Roselli said:

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.

Quoted message said:

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.

Quoted message said:

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.

Quoted message said:

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

Chalo said:

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