|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
Edward Dolan wrote:
"Tom Sherman" wrote in message ... Andre Jute wrote: A concurrent thread on a big gear range made me wonder what width one could achieve in hub gears by ignoring the recommended chainring/ sprocket ratio, which for Rohloff appears to be a fraction under 2.5 and for the Shimano Nexus 8-speed hub is specifically given as from 2.0 to 2.1. I have no idea how long the hubs would survive under abusive handling as in some of the examples below. All numbers in gear inches. With a 37-622 tyre and 46-16 gears, the Rohloff Speed Hub would give a range from a notch or two below many mountain bikes to pretty well beyond what most people could manage on the flat. Fourteen gears in gear inches developed: 22 25 28 32 37 42 47 54 61 70 79 90 102 116 Just for comparison, here are the gear inches for the 14 gears of the Rohloff with a more reasonable, and possibly permitted (I've seen it several times), 42-16 setup. Still a very respectable spread, and probably more pleasurable to use: 20 23 26 29 33 38 43 49 56 64 72 82 93 106 Adding the Schlumpf Speed Drive to a Rohloff Speed Hub seems unnecessary: it will add only four useful gears at most, the rest being duplicated. Why not consider the Schlumpf High Speed Drive [1] that offers a 2.5:1 step-up, as compared to the 1.65:1 step-up of the Speed Drive? Okay, let's look at the Shimano Nexus 8-speed hub. With a 37-622 tyre and the same 46-16 gears as inour first example, but in this case even more abusive, the Shimano Nexus 8-speed hub combined with the Schlumpf Mountain Drive would give an even wider useful spread, 14 unique gears out of 16 covering from a Himalayan low gear to 127in to pose with in cafe society. (This covers the entirely unreasonable 18 to 123in someone asked for in a concurrent thread, and a bit more.) Unreasonable for an upright bicycle, yes. However, for a recumbent bicycle, that wide gearing range is not at all unreasonable, but nearer to a necessity. The proper climbing technique on a recumbent bicycle is unlike that for an upright bicycle, where the preferred climbing technique of many is to stand and pedal at a relatively low cadence, while pulling on the handlebars to increase one's "effective" weight. Conversely, the proper climbing technique on a recumbent is to use a very high cadence (e.g. 120 RPM) and to pull back [2] as much as possible. Trying to use the upright climbing technique will result in excess lactic acid buildup with the rider then needing to stop or slow severely to recover. The (performance oriented) recumbent will also descend faster (where tight corners or rough surfaces do not limit speed too severely) than the upright. In particular, on a frontally or fully faired recumbent, the rider can pedal without increasing drag, so a very high gear can be used while going downhill. I have a couple of lowracer bicycles with gear inch range of 19-120 (achieved with a step-up jack-shaft) and a "bodysock" faired long wheel base recumbent with a range of 15-125 gear inches (achieved with a triple crank and 3x7 hub). I have found both the lowest and highest gear ratios on these bicycles useful. Gear Direct SMD 1 42 17 2 51 20 3 59 24 4 67 27 5 79 32 6 97 39 7 112 45 8 127 51 I was speaking to a guy in the parts department at Volvo in Gothenburg a few years ago, and when he heard I planted a Chevy mouse motor in one of their estates and was now supercharging it and looking to use a few gennie Volvo parts, he said thickly, "Doncha tell Warranty. Inna flash Warranty turn your ash to grash." (On a tip from this colourful fellow I ordered the parts I wanted a lot cheaper from Rolls-Royce than from Volvo; they bought them the same place but the Volvo markup was higher...) I imagine Shimano will turn one's warranty, and one's ass, to grass in a flash if they hear about a 46-16 FR tooth ratio on one of their Nexus hubs, when they went to the trouble of printing the ratio warning on the cover of the spec sheet. So let's try 38-18, which at 2.11 recurring is arguably within the permitted ratio, and can be built with Shimano's goodlooking and reasonably priced own-brand parts intended for the hub gear bikes. With the Schlumpf Mountain Drive, that gives 14 unique gears that covers everything from loaded goatherding to pretty fast touring: 31 12 37 15 43 17 49 20 58 23 71 28 82 33 94 37 It does look like iconoclasm and scoffjawing the warranty is unnecessary. With either the Rohloff or the Nexus/Schlumpf combination you can get nicely spaced gear ratios over a very wide operating band. The designers of those hubs and geared bottom bracket got it right. In fact, riding daily in the low rolling hills of West Cork, I find 38-19 sets of teeth just right on the Nexus gear hub without the need for the Schlumpf geared bottom bracket; it gives me the following gear inch development for the 8 gears, perfect for day rides on my particular countryside without ever having to push: 29 35 41 47 55 67 78 89 Would not a higher gear be useful when drafting trucks downhill? Sprockets with any number of teeth you can want are readily available, so for another use, say loaded alpine touring, I would not hesitate to change the sprocket to give a ratio that is not permitted. I think the Nexus hub is a lot sturdier than Shimano lets on, and it is widely known that the Rohloff hub is panzer. Of course, one can obtain very low gearing when the Rohloff is used in a small drive wheel, without violating Rohloff's restrictions. Lacing the large flange Rohloff hub into an ISO 349-mm hub would be challenging, if one were to use it on a bicycle such as the Tri-Sled Nitro [3]. [1] http://www.schlumpf.ch/hsd_engl.htm. [2] Clipless pedals with good retention are mandatory. [3] http://www.trisled.com.au/nitro.html. I find that I cannot comment on the above due to insufficient information posted by the two correspondents. If you wish to know what the Great Ed Dolan thinks, you will have to provide much more detail, especially more numbers if you please. My God, how do you expect anyone to determine anything from the paucity of information posted here! Ed Dolan is losing it, since he commented on the above only 28 minutes prior to this post. All this **** about hubs and gears has got my head reeling! I used to think this kind of stuff was important, but now I know better. Only nerds, jerks and dorks care about this ****, let alone post messages to newsgroups about it. But that is RBT for you - an asylum of nerds, jerks and dorks. It is the true home of Tom Sherman. He should stay there and not bother us sane and sensible types here on ARBR. Some on rec.bicycles.tech would beg to differ. -- Tom Sherman - Holstein-Friesland Bovinia "And never forget, life ultimately makes failures of all people." - A. Derleth |
Ads |
#22
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
On Feb 1, 12:19*am, "Clive George" wrote:
"Andre Jute" wrote in message ... So, the 46/16 you claim is not permissible is in fact entirely legit - it's rather easier on the hub than the minimum permissible gearing. Certainly to the engineer it is legitimate, but to the manufacturer it is not permissible because he has stated both an upper and a lower range. I say again, check the viewpoint from which I make a particular statement. That'll be the viewpoint which completely ignores what the manufacturer says, would it? That's not right, Clive. I ignored what Rohloff *didn't* say: Rohloff don't specify maximum gearing. Exactly. I apologized for confusing you with Shimano's superfluous but positive statement of maximum gearing juxtaposed with my failure to report Rohloff's strangely absent statement. No one else was confused except Carl Fogel -- which is hardly surprising, is it now? You screwed up, admit it, move on. Not at all. You'll see, when I screw up -- may you live so long as to see it -- and you discover me doing it (for which you will need that sensitivity-enhancing woman in place), I shall immediate put forward your name to the Palace for a well-deserved knighthood. How would "for services to sado-masochism, using a bicycle as his instrument of flagellation" strike you as an encomium? clive Lighten up, pal. Bicycling is only a hobby. Andre Jute Heretic |
#23
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
Andre Jute wrote:
... Never mind the gear, how do you keep your balance going up a 25% grade with a loaded bike? Sounds like an argument for credit card touring... ... Or the addition of a third wheel. -- Tom Sherman - Holstein-Friesland Bovinia "And never forget, life ultimately makes failures of all people." - A. Derleth |
#24
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
Andre Jute Wrote: On Feb 1, 12:19*am, That'll be the viewpoint which completely ignores what the manufacturer says, would it? That's not right, Clive. I ignored what Rohloff *didn't* say: Rohloff don't specify maximum gearing. Andre Jute Heretic[/color] Actually, Rohloff does state there is no maximum. http://www.rohloff.de/fileadmin/rohl...fo_2.13.en.pdf Page 13, left column near the bottom. "Larger chainrings can be used without exceptions" I've seen it elsewhere on their web site, but I can't find it right now. Dan -- Dan Burkhart |
#25
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
On Fri, 1 Feb 2008 13:35:02 +1100, Dan Burkhart
wrote: Andre Jute Wrote: On Feb 1, 12:19*am, That'll be the viewpoint which completely ignores what the manufacturer says, would it? That's not right, Clive. I ignored what Rohloff *didn't* say: Rohloff don't specify maximum gearing. Andre Jute Heretic Actually, Rohloff does state there is no maximum. http://www.rohloff.de/fileadmin/rohl...fo_2.13.en.pdf Page 13, left column near the bottom. "Larger chainrings can be used without exceptions" I've seen it elsewhere on their web site, but I can't find it right now. Dan[/color] Dear Dan, Probably this: "Of course, the use of larger chainrings is completely allowed, this increases the primary force and the entry force at the same time for the hub to reduce." http://www.rohloff.de/en/info/faq/fa...289/index.html It's worth belaboring the point, since otherwise someone might mistakenly swap in a _smaller_ chainring and destroy an expensive hub. Rohloff sets a _minimum_ front:rear sprocket ratio. A 40:17 (2.35:1) is the minimum ratio for normal riders. A 40:16 (2.50:1) is the minimum ratio for heavier riders and tandems. The 40-tooth front in the example can be increased to any size--the front:rear ratio just gets bigger. Switching to 42-tooth or 72-tooth is fine. But he 40-tooth front in the example should not be reduced--the front:rear ratio would fall below the minimum, and Rohloff expects that the increased force inside the hub would damage its gears. For example, replacing the 40-tooth front with a smaller 32-tooth would be begging for trouble, since 32:16 is only 2.00:1, well below the 2.35:1 minimum front/rear sprocket ratio. Again, the rear wheel doesn't matter because the problem occurs in the tiny gears inside the hub. Cheers, Carl Fogel |
#26
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
On Jan 31, 6:41*pm, Tom Sherman
asked: What was the prize? First Prize: a one night stay at Chateau de Smarm in Pueblo, Colorado, with your host Carl "top dung beetle" Fogel. Second Prize is, of course, a two-week stay at Chateau de Smarm. |
#27
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
On Feb 1, 2:35*am, Dan Burkhart Dan.Burkhart.342...@no-
mx.forums.cyclingforums.com wrote: Andre Jute Wrote: On Feb 1, 12:19*am, That'll be the viewpoint which completely ignores what the manufacturer says, would it? That's not right, Clive. I ignored what Rohloff *didn't* say: Rohloff don't specify maximum gearing. Andre Jute Heretic Actually, Rohloff does state there is no maximum.http://www.rohloff.de/fileadmin/rohl...hreibung/speed... Page 13, left column near the bottom. "Larger chainrings can be used without exceptions" I've seen it elsewhere on their web site, but I can't find it right now. Dan -- Dan Burkhart[/color] In that case it looks like I'll have to drop the palace a line. "Your Majesty, My cat and i would be pleased indeed If you would graciously confer an honour on Mr Clive George for promoting the product of a German manufacturer." Andre Jute |
#28
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
Thanks Carl. You're doing good. Gofer coffee. -- Andre Jute
On Feb 1, 3:01*am, wrote: On Fri, 1 Feb 2008 13:35:02 +1100, Dan Burkhart Actually, Rohloff does state there is no maximum. http://www.rohloff.de/fileadmin/rohl...hreibung/speed... Page 13, left column near the bottom. "Larger chainrings can be used without exceptions" I've seen it elsewhere on their web site, but I can't find it right now. Dan Dear Dan, Probably this: "Of course, the use of larger chainrings is completely allowed, this increases the primary force and the entry force at the same time for the hub to reduce." http://www.rohloff.de/en/info/faq/fa...ttenblattzaehn... It's worth belaboring the point, since otherwise someone might mistakenly swap in a _smaller_ chainring and destroy an expensive hub. Rohloff sets a _minimum_ front:rear sprocket ratio. A 40:17 (2.35:1) is the minimum ratio for normal riders. A 40:16 (2.50:1) is the minimum ratio for heavier riders and tandems. The 40-tooth front in the example can be increased to any size--the front:rear ratio just gets bigger. Switching to 42-tooth or 72-tooth is fine. But he 40-tooth front in the example should not be reduced--the front:rear ratio would fall below the minimum, and Rohloff expects that the increased force inside the hub would damage its gears. For example, replacing the 40-tooth front with a smaller 32-tooth would be begging for trouble, since 32:16 is only 2.00:1, well below the 2.35:1 minimum front/rear sprocket ratio. Again, the rear wheel doesn't matter because the problem occurs in the tiny gears inside the hub. Cheers, Carl Fogel |
#29
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
"Tom Sherman" wrote in message ... Edward Dolan wrote: [...] I find that I cannot comment on the above due to insufficient information posted by the two correspondents. If you wish to know what the Great Ed Dolan thinks, you will have to provide much more detail, especially more numbers if you please. My God, how do you expect anyone to determine anything from the paucity of information posted here! Ed Dolan is losing it, since he commented on the above only 28 minutes prior to this post. Your comment makes no sense to me at all, but that is becoming par for the course lately. All this **** about hubs and gears has got my head reeling! I used to think this kind of stuff was important, but now I know better. Only nerds, jerks and dorks care about this ****, let alone post messages to newsgroups about it. But that is RBT for you - an asylum of nerds, jerks and dorks. It is the true home of Tom Sherman. He should stay there and not bother us sane and sensible types here on ARBR. Some on rec.bicycles.tech would beg to differ. Regards, Ed Dolan the Great - Minnesota aka Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota |
#30
|
|||
|
|||
Hub Gears: no need to scoffjaw the warranty
"Tom Sherman" wrote in message ... Edward Dolan wrote: wrote in message ... On Jan 31, 1:18 am, Tom Sherman wrote: [Quotation marks are messed up, so I will supply my own.] "dustoyevsky's" post is fine. It is Ed Dolan's Microsoft Windows Mail 6.0 that has been mucking up posts recently. Then why aren't your posts equally messed up? The fact is that it is only posts that come from Google Groups that are messed up and then only some of them. [...] For the love of both Tullio Campagnolo and Shozo Shimano, get a real newsreader, Ed!!! Put your brain into gear and tell me why some messages from Google Groups are messed up and others aren't. Regards, Ed Dolan the Great - Minnesota aka Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
REI Warranty | Frank Drackman | Techniques | 43 | December 6th 07 03:07 AM |
KH 20 --- Warranty? | Riles | Unicycling | 19 | July 15th 07 05:36 AM |
KH Warranty? | terrybigwheel | Unicycling | 5 | June 13th 06 01:53 AM |
Warranty question | Phil Clarke | UK | 11 | November 9th 05 06:27 PM |
Gears gears gear..what to choose? | bstephens | Techniques | 8 | February 18th 04 05:06 PM |