Bottom Bracket Hub Gear

On 16 Dec 2003 16:32:40 +1050, blacktom

may have said:

Has it been done?

Yes.

Heavy, expensive, and not as efficient mechanically as a derailleur, but they exist.

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Quoted message said:

blacktom may have said:

Has it been done?

Yes.

Heavy, expensive, and not as efficient mechanically as a derailleur, but they exist.

Indeed they do:

sheldonbrown.comschlumpf.htmlOpen ↗

Matt O.

"Matt O'Toole" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

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

Quoted message said:

blacktom may have said:

Has it been done?

Yes.

Heavy, expensive, and not as efficient mechanically as a derailleur, but they exist.

Indeed they do:

sheldonbrown.comschlumpf.htmlOpen ↗

Matt O.

Go to the source: schlumpf.chhsd engl.htmOpen ↗

A common use for these is on 20" wheel bikes- folders and recumbents. The step-up gear is useful to
get reasonable gearing with standard size chainrings.

I recall that Shimano offered a 5-speed crank mounted transmission a couple years back- but that's a
fuzzy memory, and it was Japan-market-only. I have no idea whether it was ever sold anywhere else.

Jeff

Jeff Wills said:

I recall that Shimano offered a 5-speed crank mounted transmission a couple years back- but
that's a fuzzy memory, and it was Japan-market-only. I have no idea whether it was ever sold
anywhere else.

Also, back in the 1970s there was a 3-speed crank/transmission setup that was made by Dana (better
known for car/truck differentials). It had a large cast aluminum housing and a very small chainring,
and two cables for the twist shifter. My father put one on my rescued-from-the-trash Schwinn
Stingray. It worked well, but it was definitely not for weight weenies.

When I outgrew it, I continued the weird drivetrain kick with a 1977 Schwinn Caliente (Positron II
rear derailleur and front freewheeling).

Now, instead of weird drivetrains, I've graduated to weird frames (recumbents).

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the way people get hit by cars." -Robert Canon

In this month's Velo Vision (velovision.co.ukvelovision.co.ukOpen ↗ excellent magazine
btw) there is a picture of a MTB with a Rohloff mounted just above the
standard bottom bracket (see g-boxx.orgg-boxx.orgOpen ↗ ) - amazing!

Kirby

Kirby James said:

In this month's Velo Vision (velovision.co.ukvelovision.co.ukOpen ↗ excellent magazine btw) there is a
picture of a MTB with a Rohloff mounted just above the standard bottom bracket (see g-g-Open ↗
boxx.org )
- amazing!

There's also an article about a Canadian-made FWS recumbent with a Schlumpf drive- normally used in
the BB- which was adapted to be a step-up gear in a direct drive setting. The builder machined a
front hub with the internal dimensions of a bottom bracket shell, with a pawl to make the unit drive
the shell directly.

Quoted post said:

Originally posted by blacktom
Is it possible to build a hub gear into a custom bottom bracket?

Imagine the possibilities:

-No derailleurs to get damaged and a short chain line

-Change gear when you are stationary

-Outrageous gear ratios

-Up to 196 speeds for gear freeks(Rohloff 14 x 14!)

-Or 42 for regular folk (3 x 14)

Has it been done?

Brian.

Sclumpf with Rohloff gets you 28 without derailleur.

Rohloff 14X 14 pairing is only 27 distinct ratios amongst those 196 gears-lots of repeats (169). You get 13 identical flavors of your 2 middle ratios (distributed like Pascal’s Triangle).

Pairing a Rohloff with a differing ratio interval S7 or Nexus 7 gets you more distinct derailuer free ratios at lower price & weight.

Easy to get a 2 chainring Schlumpf with 3X9 dual drive gets you 104 speeds but you’ve got the f/r derailleurs).

There is someone in Michigan in the Guiness Book of Records with a 1500+ speed bike.

There were some recent threads on liquid drive and “Continuously variable" electric transmission electric transmission which effectively give you infinite ratios without deraileurs.

blacktom said:

Is it possible to build a hub gear into a custom bottom bracket?

Schlumpf.

Quoted message said:

-Outrageous gear ratios -Up to 196 speeds for gear freeks(Rohloff 14 x 14!) -Or 42 for regular folk
(3 x 14) Has it been done?

Sheldon Brown did it. I can't find it now, but he has hundreds of speeds, with a Schlumpf, a triple
crank, a 7 speed rear (now he could use a ten speed!), and a Rohloff.

With the ten speed rear, 840 speeds.

Cram that Rohloff into the front where the Schlumpf goes, and get 5,880 speeds.

Quoted message said:

Brian.

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Quoted message said:

-Or 42 for regular folk (3 x 14)

Has it been done?

Brian.

Triple chainrings combined with SRAM 3x7 (3x8, 3x9) DualDrive hubs are somewhat common in the
recumbent community. 63 (72, 81) gears.

Jeff

Rick Onanian <[email hidden]> wrote in message
news:<[email hidden]>... <snip>

Quoted message said:

Sheldon Brown did it. I can't find it now, but he has hundreds of speeds, with a Schlumpf, a
triple crank, a 7 speed rear (now he could use a ten speed!), and a Rohloff.

With the ten speed rear, 840 speeds.

Cram that Rohloff into the front where the Schlumpf goes, and get 5,880 speeds.

Quoted message said:

Brian.

Sheldon better watch it. Put that in high gear and he'll exceed the speed of light. Then he'll go
backwards in time and get his beard back.

Jeff

Pashley Cycles in the UK have specced a bike for the british police force with hub gears and a
deraillier. In a interesting phone call I just went 'what!' and my mouth opened and shut.

Its random, but Its allegadly very durable!

/Mr Ferret

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

Quoted message said:

Is it possible to build a hub gear into a custom bottom bracket?

Imagine the possibilities:

-No derailleurs to get damaged and a short chain line

-Change gear when you are stationary

-Outrageous gear ratios

-Up to 196 speeds for gear freeks(Rohloff 14 x 14!)

-Or 42 for regular folk (3 x 14)

Has it been done?

Brian.

--

Thanks for all your replies. I was not aware of the Schlumpf 2 speed bottom bracket. And although I had read much of Sheldon Brown's excellent site, I had missed his article on hub gears. Using his gear table (which includes ratios for Rohloff hub gears) I find that with a Schlumpf/Rohloff combination the gear inches go from 10" to 132" in the low Schlumpf to 23" to 177" in the high with a 50 tooth and 45 tooth chainrings respectively. However, as MEB previously stated most of the ratios are duplicated apart from the highs and lows.

Brian.

Quoted post said:

Originally posted by blacktom
Thanks for all your replies. I was not aware of the Schlumpf 2 speed bottom bracket. And although I had read much of Sheldon Brown's excellent site, I had missed his article on hub gears. Using his gear table (which includes ratios for Rohloff hub gears) I find that with a Schlumpf/Rohloff combination the gear inches go from 10" to 132" in the low Schlumpf to 23" to 177" in the high with a 50 tooth and 45 tooth chainrings respectively. However, as MEB previously stated most of the ratios are duplicated apart from the highs and lows.

Brian.

Since 23/10 =2.3 while 177/132 =1.45, you've got at least one math error.

f you go with a mountain drive (2.5: reduction) with bigger chainring(s) rather than a speed drive (1.65: 1 overdrive), you get broader range and less quasi duplication.

Tim McNamara said:

There's also an article about a Canadian-made FWS recumbent with a Schlumpf drive- normally used
in the BB- which was adapted to be a step-up gear in a direct drive setting. The builder machined
a front hub with the internal dimensions of a bottom bracket shell, with a pawl to make the unit
drive the shell directly.

A FWD FWS recumbent that uses a Schlumpf BB as a jackshaft/step-up. <barcroftcycles.comoregonOpen ↗
web.jpg>.

Tom Sherman - 41½ N, 90½ W

Quoted post said:

Originally posted by Tom Sherman

BTim McNamara said:

There's also an article about a Canadian-made FWS recumbent with a Schlumpf drive- normally used
in the BB- which was adapted to be a step-up gear in a direct drive setting. The builder machined
a front hub with the internal dimensions of a bottom bracket shell, with a pawl to make the unit
drive the shell directly.

A FWD FWS recumbent that uses a Schlumpf BB as a jackshaft/step-up. <barcroftcycles.comoregonOpen ↗
web.jpg>.

Tom Sherman - 41½ N, 90½ W [/B]

Is this a stepup with the internal gears or only the shell/bearings of a tandem Schlumpf BB with all stepup throught the chainrings/sprockets?

On a competition lowracer, it seems unlikely one would add the 5% efficiency loss of epicyclic gears in the BB.