Rohloff question

Quoted message said:

I have a Rohloff 500/14 wheel, around which I am building a FWD
machine.

My question is, on the side where the shifter cables go in, there is a
long arm that attaches to the chainstay. Is this arm so long for any
particular reason?

IIANM, if it was substantially shorter, the force it generates in
reaction could bend the stay.
--
Typoes are a feature, not a bug.
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Thanks.

If there was a brake there, such as a coaster brake, I could understand
it but what could create a substantial force there.

I've only ridden that wheel around the block a couple of times, about 3
years ago and, at that time, I'm not even sure if I secured that arm at
all.

Kind regards.

Lewis.

********

Quoted message said:

My question is, on the side where the shifter cables go in, there is a
long arm that attaches to the chainstay. Is this arm so long for any
particular reason?

It's usually attached to the chainstay, although I have it
attached to the seatstay on my bike.

It's long because the Rohloff hub steps the drive torque up
substantially (by a factor of about 3.6) in its lowest gear,
more so than other internal-gear hubs do.

Quoted message said:

I've only ridden that wheel around the block a couple of times, about 3
years ago and, at that time, I'm not even sure if I secured that arm at
all.

If you only use gears near gear 11 (direct drive) and don't pedal
hard, not much torque support is required, and the axle nuts
(or QR, whichever you have) might suffice to hold the axle in
place--but that's not good practice.

Tom Ace

Quoted message said:

Thanks.

If there was a brake there, such as a coaster brake, I could understand
it but what could create a substantial force there.

I've only ridden that wheel around the block a couple of times, about 3
years ago and, at that time, I'm not even sure if I secured that arm at
all.

The internal gears use a sun-and-planet gear system for the various
ratios.Since the sun gear must stay in a fixed position, and the axle
holds the sun gear in place, the axle must be prevented from spinning.
On the Rohloff, it's prevented from spinning by the torque arm since
the axle uses a conventional quick release. As an alternative, Rohloff
offers a fitting that uses the dropout slot to take the torque. It
looks something like this:
http://www.antbikemike.com/images/Bikes/Rohloff/dropoutbig.jpg

If you'd ridden the wheel for more than a couple blocks, particularly
up some steep hills (where the gears would exert a lot of leverage on
the axle), you'd find out how much that axle wants to spin.

Jeff

limeylew said:

Thanks.

If there was a brake there, such as a coaster brake, I could understand
it but what could create a substantial force there.

I've only ridden that wheel around the block a couple of times, about 3
years ago and, at that time, I'm not even sure if I secured that arm at
all.

It is undoubtedly an anti-rotation arm, since on an internal gear hub in
low gears, there is a substantial bit of torsion twisting the hub
backwards. It's not enough to really bend the stay, though.

--

David L. Johnson

__o | Let's be straight here. If we find something we can't
_`\(,_ | understand we like to call it something you can't understand, or
(_)/ (_) | indeed even pronounce. -- Douglas Adams

Thanks for your help, Jeff.

Mike Flanagan has an interesting setup there in that photo.

Kind regards.

Lewis.

*********

Thanks for all the helpful replies, guys, I appreciate it.

Lewis.

******

Per [email hidden]:

Quoted message said:

My question is, on the side where the shifter cables go in, there is a
long arm that attaches to the chainstay. Is this arm so long for any
particular reason?

Dunno, but look closely at the dingus that arm attaches to on the Rohloff end.

It's a metal plate attached to the hub by five (?) Torx screws. I think
Rohloff calls it an "axle plate".

That plate can be replaced by a slightly-different plate and the new
plate can be interfaced with a little thing about 3 inches long that
bolts to your bike's disk caliper mounts - and the long arm can
be done away with while retaining use of the disc caliper.

Rohloff calls the three-inch thingie a "SpeedBone".

Also, I've heard (but wouldn't want to be the guinea pig...) that the
indentation on the axle plate that's already there conveniently lines up
with an extra long screw with a bunch of nuts on the protruding
portion run through one of the unused disc brake mounts. Maybe somebody
who knows can comment on the safety of that arrangement.
--
PeteCresswell

JeffWills said:

http://www.antbikemike.com/images/Bikes/Rohloff/dropoutbig.jpg

Nice hub. Tacky QR skewer, though. ;^)

Chalo

Chalo aka Chalo Colina said:

JeffWills said:

http://www.antbikemike.com/images/Bikes/Rohloff/dropoutbig.jpg

Nice hub. Tacky QR skewer, though. ;^)

Do people need to have "open" and "close" on the quick release (QR)
lever to figure out how the thing works?

--
Tom Sherman

Quoted message said:

Thanks for your help, Jeff.

Mike Flanagan has an interesting setup there in that photo.

Kind regards.

Lewis.

*********

FWIW: Here's a Rohloff incorporated into a FWD drivetrain:
http://www.ohpv.org/albums/bm2004/velox/pages/velox5.htm

The geometry might *look* a little funny (yep, it's got "reverse"
rake), but I was able to ride that machine with only one false start.
Impressive, considering that I was pedaling with the sides of my feet
since I'm about 8 inches taller than the rider the bike was adjusted
for. My knees ended up outside the ends of the handlebars.

Jeff

Thanks, Jeff, that is really interesting.

Kind regards.

Lewis.

********

Quoted message said:

Thanks.

If there was a brake there, such as a coaster brake, I could understand
it but what could create a substantial force there.

Just earlier this week, I tore the flats out of an anti-rotation axle
washer on a Sachs Spectro 7 hub. I was using the top gear at that
time. There is definitely some significant reaction force at the axle
when there is a large difference between input and output ratios.

I machined a much more substantial anti-rotation washer from a solid
steel bar, and then I hardened it. With any luck, that's all the
retrofitting I'll need to do to keep from spinning the axle again.

Chalo Colina

Quoted message said:

Quoted message said:

JeffWills said:

http://www.antbikemike.com/images/Bikes/Rohloff/dropoutbig.jpg

Quoted message said:

Chalo aka Chalo Colina said:

Nice hub. Tacky QR skewer, though. ;^)

Johnny Sunset aka Tom Sherman said:

Do people need to have "open" and "close" on the quick release (QR)
lever to figure out how the thing works?

Mandated by CPSC for al sold in USA.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

quote='Chalo said:

Thanks.

If there was a brake there, such as a coaster brake, I could understand
it but what could create a substantial force there.

Just earlier this week, I tore the flats out of an anti-rotation axle
washer on a Sachs Spectro 7 hub. I was using the top gear at that
time. There is definitely some significant reaction force at the axle
when there is a large difference between input and output ratios.

I machined a much more substantial anti-rotation washer from a solid
steel bar, and then I hardened it. With any luck, that's all the
retrofitting I'll need to do to keep from spinning the axle again.

Chalo Colina[/QUOTE]

Chalo. I have the same hub and had precisely the same thing happen. When the axle spun backwards, it screwed up the bearing adjustment as well. I am sure you know to check for that.
My bike came with just one anti-rotation washer on the non drive side, and after I tore the flats out of it, I also made a more substantial one.
Dan

Dan Burkhart said:

Chalo said:

Just earlier this week, I tore the flats out of an anti-rotation axle
washer on a Sachs Spectro 7 hub.

....

Quoted message said:

Quoted message said:

I machined a much more substantial anti-rotation washer from a solid
steel bar, and then I hardened it.

Chalo. I have the same hub and had precisely the same thing happen.
When the axle spun backwards, it screwed up the bearing adjustment
as well. I am sure you know to check for that.
My bike came with just one anti-rotation washer on the non drive side,
and after I tore the flats out of it, I also made a more substantial one.

The bearing adjustment on my hub was completely hosed. I think the
axle made about three revolutions in the frame. Even before I machined
the new anti-rotation washer, I machined a wrench for the weird slotted
adjustment nut on the left side of the axle, so I could reset the
bearing preload.

I had enough previous experience with Sachs gearhubs that I knew it
would be a good idea to use another anti-rotation washer on the right
side. Unfortunately, because of the thick aluminum dropouts on my
frame, there was not enough threaded length on that side to mount both
a tabbed washer and a clickbox guard. So I opted for the guard.

Chalo

Here is a twist grip control for the Rohloff hub shown on the right
side of this handlebar:

http://www.mittelmeyer.de/02210010.JPG
http://www.mittelmeyer.de/02210003.JPG

Jobst Brandt