A Cycling & bikes forum. CycleBanter.com

Go Back   Home » CycleBanter.com forum » rec.bicycles » Techniques
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Hub Gears: no need to scoffjaw the warranty



 
 
Thread Tools Display Modes
  #21  
Old February 1st 08, 02:14 AM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Tom Sherman[_2_]
external usenet poster
 
Posts: 9,890
Default 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  
Old February 1st 08, 02:39 AM posted to rec.bicycles.tech
Andre Jute
external usenet poster
 
Posts: 433
Default 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  
Old February 1st 08, 02:49 AM posted to rec.bicycles.tech
Tom Sherman[_2_]
external usenet poster
 
Posts: 9,890
Default 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  
Old February 1st 08, 03:35 AM posted to rec.bicycles.tech
Dan Burkhart[_44_]
external usenet poster
 
Posts: 1
Default 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  
Old February 1st 08, 04:01 AM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 7,934
Default 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  
Old February 1st 08, 04:03 AM posted to rec.bicycles.tech, alt.rec.bicycles.recumbent
Ozark Bicycle
external usenet poster
 
Posts: 3,591
Default 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  
Old February 1st 08, 04:11 AM posted to rec.bicycles.tech
Andre Jute
external usenet poster
 
Posts: 433
Default 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  
Old February 1st 08, 04:13 AM posted to rec.bicycles.tech
Andre Jute
external usenet poster
 
Posts: 433
Default 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  
Old February 1st 08, 04:17 AM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Edward Dolan
external usenet poster
 
Posts: 14,212
Default 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  
Old February 1st 08, 04:23 AM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent,rec.bicycles.misc
Edward Dolan
external usenet poster
 
Posts: 14,212
Default 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

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

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


All times are GMT +1. The time now is 08:31 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 CycleBanter.com.
The comments are property of their posters.