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#21
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Shimano Nexus 8-speed Hubs
Sheldon Brown wrote:
Chalo wrote: Confound it. True to clueless form, Shimano have dished up a heaping helping of asymmetrical flange offset on a hub that didn't need to have any. 2.7 mm is a "heaping helping" of asymmetry? Most non-flip-flop hubs have at least this much asymmetry. Ah, I looked at your photo of the hub without the roller brake or its fixing nut, and I saw a bunch of offset. But as installed, the offset is pretty reasonable. It does make me wonder why they wouldn't make it genuinely symmetrical for ease of wheelbuilding, though. I continue to be completely vexed by the Sturmey Archer gearhubs that build into dished wheels. I reckoned Shimano had given us another such abomination, but I was wrong. Another nugget on the towering mountain of reasons not to buy their crap-- like I really needed another one. "Crap?" This is the best multi-speed hub you can buy for less than $700! Sounds like predjudice to me. I beg to differ-- I have owned both Sachs/SRAM 7 speed hubs and Shimano 7-speed hubs, and the difference is astounding. SRAM S7 hubs give a wider range of gears and a *much* smaller amount of drag, while seeming generally more rugged. I have never heard of someone wearing out or overloading a Sachs or SRAM 7-speed hub, but I have heard direct accounts of Nexus hub failures (requiring gear body replacement) from local shop mechanics. My two Nexus 7 hubs are on small-wheeled art bikes that doesn't get very many miles, so I've not laid waste to them yet. When I ride my Nexus-7-hubbed bikes, I feel like I'm losing a whole gear ratio to system inefficiency. Admittedly this is a tough thing to quantify, but I don't find my SRAM hubs to display any more noticeable drag than my derailleur bikes. They seem to drive at least as freely as my Rohloff hub. The Nexus 8 hub is going to have to be a *whole lot better* than the Nexus 7 before it can be considered equal to or better than the SRAM S7. It doesn't have a wider overall range than the SRAM S7, and it obviously uses more sets of plantaries. The presence of a true 1:1 ratio in the new Nexus hub bodes well, but I suspect that in the field it will prove to be a lesser product than the SRAM. Chalo Colina |
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#22
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Shimano Nexus 8-speed Hubs
Chalo wrote:
Sheldon Brown wrote: Chalo wrote: Confound it. True to clueless form, Shimano have dished up a heaping helping of asymmetrical flange offset on a hub that didn't need to have any. 2.7 mm is a "heaping helping" of asymmetry? Most non-flip-flop hubs have at least this much asymmetry. Ah, I looked at your photo of the hub without the roller brake or its fixing nut, and I saw a bunch of offset. But as installed, the offset is pretty reasonable. It does make me wonder why they wouldn't make it genuinely symmetrical for ease of wheelbuilding, though. I continue to be completely vexed by the Sturmey Archer gearhubs that build into dished wheels. I reckoned Shimano had given us another such abomination, but I was wrong. Another nugget on the towering mountain of reasons not to buy their crap-- like I really needed another one. "Crap?" This is the best multi-speed hub you can buy for less than $700! Sounds like predjudice to me. I beg to differ-- I have owned both Sachs/SRAM 7 speed hubs and Shimano 7-speed hubs, and the difference is astounding. SRAM S7 hubs give a wider range of gears A bike with an Alivio group will have a wider range than a bike with Dura-Ace. Does that mean Alivio is better than Dura-Ace? The Sram 7-speed and the Nexus 8 speed have the same range. Sram 39/16 gives 37.5 - 114.5 inches Nexus 8 42/16 gives 37.4 - 114.5 inches with the same wheel size. See: http://sheldonbrown.com/gears/internal.html The Sram is afflicted with some excessively large jumps in the middle of its range. 4 - 5 is a whopping 24% jump, 65.8 to 81.6 inches in the example shown. 3 - 4 isn't much better, 23.5% (53.3 to 65.8 inches) The jumps on the Sram 7-speed, from bottom to top a 19.3%, 19.1%, 23.5%, 24.0%, 19.4%, 17.6% The worst jump on the Shimano is 5 - 6, 22.3% (70.0 - 86.7 in the example listed.) The jumps in the Nexus 8 a 22.2%, 16.1%, 13.8%, 17.5% 22.3% 16.0% and 13.8% These seem a lot friendlier to me. and a *much* smaller amount of drag, That is not a universally held opinion. In any case, the 8-speed Nexus is touted to be rather more efficient than the 7-speed. I do own a Nexus 7, replaced a Sturmey-Archer FM 4 speed, and the Nexus seemed noticeably easier rolling than the Sturmey. while seeming generally more rugged. Some parts are, some parts aren't. Shimano's sheltered shift linkage is very much less prone to damage than Sram's "clickbox" hanging off the end of the axle. I personally see no clear winner between the two 7-speed models, but 8 trumps 7. I have never heard of someone wearing out or overloading a Sachs or SRAM 7-speed hub, but I have heard direct accounts of Nexus hub failures (requiring gear body replacement) from local shop mechanics. My two Nexus 7 hubs are on small-wheeled art bikes that doesn't get very many miles, so I've not laid waste to them yet. When I ride my Nexus-7-hubbed bikes, I feel like I'm losing a whole gear ratio to system inefficiency. On the "small wheeled art bikes?" Doesn't sound to me like a particularly valid basis for comparison. Admittedly this is a tough thing to quantify, but I don't find my SRAM hubs to display any more noticeable drag than my derailleur bikes. They seem to drive at least as freely as my Rohloff hub. The Nexus 8 hub is going to have to be a *whole lot better* than the Nexus 7 before it can be considered equal to or better than the SRAM S7. From what I hear, it is. Not only more efficient, but with better shifting under load, and combining the nice gear spacing of the Shimano 7 with the overall range of the Sram 7. It doesn't have a wider overall range than the SRAM S7, and it obviously uses more sets of plantaries. The presence of a true 1:1 ratio in the new Nexus hub bodes well, but I suspect that in the field it will prove to be a lesser product than the SRAM. There are actually quite a few of them in the field...what's new is the availability of loose hubs. The ones on the road came on complete bikes...we sell several models with this hub. Everybody I've spoken to who has bought one loves it. I think you're a bit too quick to condemn a product that you evidently haven't even tried, just on the basis of what you "suspect." Sheldon "Hope To Get Mine On The Road Soon" Brown +--------------------------------------------+ | Opinions founded on prejudice are always | | sustained with the greatest violence. | | --Hebrew Proverb | +--------------------------------------------+ 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 |
#23
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Shimano Nexus 8-speed Hubs
"Sheldon Brown" wrote in message ... Pete Biggs wrote: Besides the extra gear, and the silent clutch, are there any differences in terms of perfomance, durabilty and weight between it and the Nexus 7 hub? The Nexus 8 is supposedly more efficent and durable, and better able to withstand shifting under load. It is also heavier, about 1.8 kg. I do not follow this segment of the market. Why do people want an internal geared hub? It seems incredibly complicated. -- Jay Beattie. |
#24
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Shimano Nexus 8-speed Hubs
Jay Beattie wrote:
I do not follow this segment of the market. Why do people want an internal geared hub? It seems incredibly complicated. Perhaps you would be in the market for a car with an external derailleur system then? On one hand, such a car would be simpler, possibly more efficient, and probably lighter than one with a gearbox. On the other, it would throw its chain at inopportune times and wear out quickly, all the while making a disgusting mess, demanding constant maintenance, and likely posing a operating hazard. This correlates nicely to my opinion of derailleur bikes as compared to gearhub bikes. Subtract the hazardous operation, and substitute a structurally flawed rear wheel. Chalo Colina |
#25
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Shimano Nexus 8-speed Hubs
Sheldon Brown wrote:
The jumps on the Sram 7-speed, from bottom to top a 19.3%, 19.1%, 23.5%, 24.0%, 19.4%, 17.6% The jumps in the Nexus 8 a 22.2%, 16.1%, 13.8%, 17.5% 22.3% 16.0% and 13.8% While I've never had any objection to the gear distribution of any of my gearhubs, it's true that the Nexus 8 looks better in that regard. Shimano's sheltered shift linkage is very much less prone to damage than Sram's "clickbox" hanging off the end of the axle. That's true. It's also a lot more vexing to connect and disconnect when you get a flat. I remember fidgeting with the shift cable on my cargo bike for about 30 minutes one night before giving up and riding in the few gears I could get. Back at home, with decent lighting and all my tools, it was not too big an ordeal to get the thing working properly-- but it still took more of a procedure than the other gearhubs I've used. I have been wondering: whatever became of the Sturmey Archer 8-speed hub? It looked like it had a cable attachment that was inboard of the dropout, but simpler than that of the Nexus. I personally see no clear winner between the two 7-speed models, but 8 trumps 7. I can't see how you could have ridden both the SRAM S7 and the Nexus 7 and found them comparable. I am glad that I bought my Nexus 7 hubs below dealer cost on eBay, because I was disappointed with them after having ridden only the SRAM. If not for that, I suppose I would have found the Nexus OK. The favorable impressions I have had of my Nexus 7s are these: The axles have not bent or broken (nor have any of my gearhubs' axles). There have been no shifting problems that I could not adjust away. They have never left me stranded or stuck in only one gear. --That's not too bad, considering the possibilities. Better than derailleurs, in any case. When I ride my Nexus-7-hubbed bikes, I feel like I'm losing a whole gear ratio to system inefficiency. On the "small wheeled art bikes?" Doesn't sound to me like a particularly valid basis for comparison. Not all choppers are as efficient as normal bikes, but mine is. Here's an early revision of my Nexus 7 equipped chopper that has accumulated the most mileage: http://deadbabybikes.org/bikes/choppa.htm At this time I use a Tioga Comp Pool in the front and a Primo Comet 2.1 in the back, with about 65 and 90 psi respectively. It think it warrants a direct efficiency comparison to my SRAM-hubbed Surly 1x1 with Ritchey Moby Bites. My other Nexus 7 equipped bike is a 3-wheeled load-carrying platform, and you'd be correct to assume that it doesn't constitute a fair comparison to a regular bike. Sheldon "Hope To Get Mine On The Road Soon" Brown I hope you are right that the Nexus 8 is a categorical improvement over the Nexus 7. +--------------------------------------------+ | Opinions founded on prejudice are always | | sustained with the greatest violence. | | --Hebrew Proverb | +--------------------------------------------+ Having been ripped off, let down, and seriously injured by Shimano products, I will no longer give Shimano the benefit of the doubt as to whether their junk is satisfactory. I will leave it to more credulous consumers to do the proof testing that Shimano evidently decline to do themselves. Chalo Colina |
#26
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Shimano Nexus 8-speed Hubs
Ah, things are so much better in the frozen north. We have had the 8
spd, in stock, for three or four months now. But, and that's in big letters, does anyone have any leads on 'alternative' shifting possibilities? The old Sachs 5-spd 2-cable, horrid plastic shifter (25000 km, before stolen) at least let you put the shifter where you wanted it. And I want the 8-spd on my Surly, with drops. In article , Sheldon Brown wrote: Pete Biggs wrote: Besides the extra gear, and the silent clutch, are there any differences in terms of perfomance, durabilty and weight between it and the Nexus 7 hub? The Nexus 8 is supposedly more efficent and durable, and better able to withstand shifting under load. It is also heavier, about 1.8 kg. Sheldon "Win Some, Lose Some" Brown +---------------------------------------------+ | Do not needlessly endanger your lives | | until I give you the signal. | | --Dwight D. Eisenhower | +---------------------------------------------+ 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 |
#27
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Shimano Nexus 8-speed Hubs
Chalo wrote:
-snip much. Yes, this is picayune- I continue to be completely vexed by the Sturmey Archer gearhubs that build into dished wheels. I reckoned Shimano had given us another such abomination, but I was wrong. Which product? Although the ubiquitous AW _can_ have dish it usually doesn't. Depends on left side axle spacing, which is quite variable. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
#28
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Shimano Nexus 8-speed Hubs
Pete Biggs wrote:
-snip- the Nexus 7 hub? The Nexus 8 "Sheldon Brown" wrote -snip- is supposedly more efficent and durable, and better able to withstand shifting under load. It is also heavier, about 1.8 kg. Jay Beattie wrote: I do not follow this segment of the market. Why do people want an internal geared hub? It seems incredibly complicated. -- Jay Mostly, no derailleur. Although I own both, there are riders who choose a gearbox to obviate chain falling off, to get a chain cover, to avoid bent/rusted/colicky derailleurs, for faster shifts ( click to low at stoplights, click to low at a near dead stop halfway up a hill), for quieter operation, for cleaner appearance, for longer drive train wear (can use fat $9.95 chain), and 'just because' (celebrate diversity). There are as many reasons as riders but we find that when there are several on the showroom floor, some are just drawn to them. Which is the whole idea, I think! And it isn't at all 'incredibly complicated' to the user. Quite the inverse. Internal hubs might as well have little robotic gerbils in there for all the average user knows. Or cares. I especially like the SRAM sevens because they've made more non-cyclists into cyclists here than any product in recent memory. Something derailleurs are just not all that good at. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
#29
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Shimano Nexus 8-speed Hubs
Jay Beattie wrote:
I do not follow this segment of the market. Why do people want an internal geared hub? It seems incredibly complicated. Ease of maintenence, for one. Secondly, it's less complicated *from the user point of view* by far. Simply hop on the bike and go. No derailleur to adjust, front or rear. Being able to shift while stopped at a stoplight is also a plus. IOW, it's great for city bikes. BTW, I've got a triple and a 7 speed cassette. I only use about 4 gears plus the granny gear to get up College Hill (Where Brown U is in Providence RI). An 8 speed internal hub would be plenty for me. -- BMO |
#30
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Shimano Nexus 8-speed Hubs
A Muzi wrote:
Chalo wrote: I continue to be completely vexed by the Sturmey Archer gearhubs that build into dished wheels. I reckoned Shimano had given us another such abomination, but I was wrong. Which product? Although the ubiquitous AW _can_ have dish it usually doesn't. Depends on left side axle spacing, which is quite variable. The Elite 5 was the last gearhub I built into a needlessly dished wheel. I think is was spaced 126mm or so. I don't remember the one before that, but it also had an aluminum shell. Chalo Colina |
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