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New Shifters that Shift When You're Still
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 |
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#2
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New Shifters that Shift When You're Still
"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 |
#3
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New Shifters that Shift When You're Still
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 |
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New Shifters that Shift When You're Still
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 |
#5
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New Shifters that Shift When You're Still
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 |
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New Shifters that Shift When You're Still
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 |
#7
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New Shifters that Shift When You're Still
"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 |
#8
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New Shifters that Shift When You're Still
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 |
#9
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New Shifters that Shift When You're Still
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. |
#10
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New Shifters that Shift When You're Still
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 |
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