Rohloff Strip to Axle and Rebuild Videos (English)

[Beave]

Thanks to Expr for the tips and Wheezy for the link to inspiration:

http://www.youtube.com/watch?v=lS6kj8g5On8

http://www.youtube.com/watch?v=Y-1iPbYra58

[expr]

Outstanding Beave, great video with loads of info, glad it all went well.

[Beave]

Thanks Dave,

I noticed a couple of things that could be interpreted as errors or things I could have explained better, but figure that was good enough to get most folks through the operation if they choose to take it on.

What I learned is that I can watch every single available Rohloff video, study every exploded diagram and such, but the real intimate knowledge of how the hubs components work together comes from taking it apart and playing with all the pieces. Hats off to the designers at Rohloff. Truly a fascinating piece of engineering.

[Beave]

One thing I still don't understand, even after taking the hub apart:

I know that the clutch ring (Part # 26) is spring loaded to contact the sun gear for locking ring gear 2 into a 1:1 ratio in gears 1, 2, 4, 8, 9 and 11, but, what disengages this clutch? What pushes on it to compress it back away from making contact with the sun gear 2-2?

Or maybe this is another misleading interpretation of the Rohloff shifting shaft animation? Meaning that, although it is pictorially shown as being disengaged, it is really always engaged, and as long as either of the two shifting pawls that contact the sun gears ahead of the clutch are engaged, then they overpower the clutch and cause it to freewheel or ratchet?

[expr]

Hi Beave,

I have spoken with a friend at Rohloff regarding the silent ring as to their intended use and here is what he said.....

"The silent ring is there to dampen a freewheel noise which only occurs when peddling in gears 3, 5, 6, and 7 as well as their upper 7 twins 10, 12, 13 and 14. In these gears (only when peddling forwards) the sun gear#3 rotates much faster than the sun gear #1 and this results in extra noises as sun gear #3 ratchets over the clutch ring. The silent ring simply keeps these two components at a safer distance apart and helps reduce the noise that can be produced by them."

I also asked about the clutch interaction but unfortunately I think the question was misinterpreted as to the clutch that sits up at the driver end, but in answer to your question it is my belief no having looked a little more closer at my strip down pictures and animations that the sun gear and clutch ring interaction are always together and as you suggest are only brought in to service when the pawl is commanded to open. I will have to clarify this at some point next time I go in to the hub.

Dave.

[Beave]

Hey Dave,

Thanks for posing the question to the officials at Rohloff. That is neat that you have friends working at the company!

That is a very satisfying answer as to the purpose of the silent ring; I can clearly imagine in my head what is being explained. And it seems to answer the second question as well, despite the misinterpretation. No need for the silent ring in gears 1, 2, 4, 8, 9 and 11 clearly indicates that these gears (the only ones that make use of that particular clutch ring) are 1:1 with sun gear 3 which then makes the silent ring not needed. Whereas the other gears always need the dampening, since that particular clutch is always engaged and when ring gear 2 is not 1:1, all the other gear combos are overun by sun gear 3.

It is nice to know that the official Rohloff shifting shaft video is in fact a bit misleading. But of course this raises another question; Why does the ring gear 1 clutch have a retracted mode? Maybe the mirror-image construction of the twin planet carrier dictates which features are dominant in determining gear ratio, and maybe that dominance switches as seen in the difference in the ring gear 1 side (dominant clutch ring that truly disengages with slave pawls vs. the ring gear 2 side (slave clutch that is always engaged with dominant pawls)? Any thoughts on that Dave? Why else would Rohloff go through the trouble of engineering in and machining another ramp into the shifting axle for the ring gear 1 clutch?

And by the way, let me know if you're still enjoying the conversation. I could go back and forth about such things for awhile.

I thought it was odd that I did not notice extra pedaling noise during my tests, but then I was not expecting louder pedaling noises. Now that I know what to look for, I think I'll strip it down again and have another listen w/o the silent ring.

[expr]

Hi Beave,

yes no problem to carry on, and to add to my last thread my friend came back to me with some more information. just to clarify a few points. This is to clarify the actual purpose of the clutch and what its movements achieve.......

The clutch sleeve connects with the ring-gear connector (part #37 on the
explosion diagram) inside the sun gear #3.

This then controls whether the sun gear #3 is fixed with the ring gear
#2 or not.
If they are connected (clutch sleeve positioned furthest from the driver
side, then the planetary gear-unit #3 rotates with a 1:1 ratio.
If they are not connected (clutch sleeve positioned furthest from the
brake-disc side, then the planetary gear-unit #3 rotates with a 1:2 ratio.


And this next statement also clarifies the purpose of the silent ring etc......


To further clear up a few misconceptions, the clutch ring is not
mechanically forced to move at all. The movement that occurs and that is
illustrated in the animations, is simply caused by the rotating
direction of sun gear #1. If the sun gear rotates backwards, then this
component forces the clutch ring away as this freewheel element
operates. If the sun gear #1 rotates forward, then the clutch ring is
engaged and the two components are pulled together.

The clutch sleeve however is forced to move. This occurs between gears
#7 and #8 to shift the third planetary gear set from a 1:2 ratio (lower
7 gears) into a 1:1 ratio in gears #8 - #14.


Don't forget if you are going to simulate the noise created by the silent ring that you will have to drive the hub by the sprocket and not the output ring gear, this will then produce the extra noise in the listed gears.

Regards


Dave.

[Beave]

Hi Dave,

Thanks for expanding on yesterdays explanations. However, I think we may have gotten our wires crossed, or perhaps your friend misunderstood my babble if he's been reading from these posts. I was talking about parts #14 and #15 in the diagram, and how that clutch interaction differs from the clutch #26; Meaning, why do clutch components 14 and 15 need to have the ability to be retracted, as opposed to the always engaged clutch 26. I was thinking this could be since ring gear 1 is driving the planet carrier, whereas ring gear 2 is being driven *by* the planet carrier. For a moment, I was thinking "why not just leave parts 14 and 15 always engaged, with the ability to ratchet over themselves". But pondering this further leads me to believe that whatever locking mechanism (clutch or pawls) that comes first as the power flows from sprocket to wheel, is the one that becomes the dominant feature determining gear ratio.   

It is good to know that pictorially, the shifting shaft video is correct. I guess it is just the fact that the gears do not rotate in the animation that can be misleading.

[Beave]

Hmm. Well, I couldn't tell much difference with and without the silent ring, while pedaling forward in those certain gears or any gear for that matter. Regardless, the silent ring is back in and will stay in, because nobody wants to hear noise while pedaling.

So before I forget; From our learnings in this topic, I have dispelled another of my beliefs. That being that the silent ring is important dimensionally to the overall fit of the hub. I must have made a mistake during my first reassembly that made the hub feel "looser". Conveniently, I blamed the silent ring and not my clumsy hands for the poor fitup

So to end my evening on a nice note, my wife asks if I will put my bike together so we can go ride tomorrow. I comply, and while torquing (to the spec'd value) the hub cap bolts into the hub shell, I sheared a screw head off. 
Lucky for me there was enough of the screw sticking up that I was able to indent the top face and back it out with a punch and hammer. Phew! Assuming I can track down some M4x10 screws tomorrow, I do look forward to riding again!

[expr]

Hi Beave,

I have asked my friend to look at the other clutch description and try and make a little more sense of it, in the meantime I will have a look and see what's going on. I've had a late night tonight so will have a look as soon as poss. The screw is a bit of a pain, hope you get it sorted out OK I always use loctite 243 and don't go as tight, this seems to help.

My wife is just the same, she says I live in the garage most of the time so tell your wife she's not alone.

Speak soon

Dave.

[Beave]

Lucky for me I was able to source 8 new screws for the hubcap, although they are now 2.5mm hex drive as opposed to Torx 20.

Riding the local trails today with my wife was excellent and certainly confirmed that the hub was reassembled correctly. Although it certainly seems louder than I remember, both when coasting and while pedaling; especially gear 7. Maybe it will take a while for the oil to soak all the parts again. I played with it so much when disassembled that it seems like almost all the residual oil was removed, and I only had a little less than 10ml saved to put back in the hub. No doubt it will be thirsty when the next oil change interval comes around.

The only downside of the day....... I had to tune the front and rear deraileurs on my wifes bike prior to leaving for our ride. You have to love those little reminders of why you got a Rohloff in the first place.

Looking forward to hearing more from you and your friend, Dave.

[expr]

Hi Beave,

Hre is a little more info regarding the clutch at the driver end.....


The clutch components #14 and #15 move from inside the driver (i.e. not
connected with the sun gear #1) to almost outside where they connect and
engage sun gear #1.

In the inside position, the driver rotates only the ring gear. If
however this clutch sleeve moves, allowing the clutch ring to move
outwards and connect with sun gear #1, then both ring gear and sun gear
will be fixed and forced to rotate in a 1:1 ratio.

The 1:1 transmission ratio of the first planetary gear set only occurs
in gears #4, #6 and #7 as well as their upper 7
twins (#11, #13 and #14).

I hope this helps clear things up a bit.

[Beave]

Hey Dave,

Yeah, sorry for asking you to answer that. I do clearly understand the driver clutch motions, but did have a lapse in thinking when pondering why there was a need to be able to disengage the clutch. Obviously not the same scenario that is occuring on the other end of the twin planet carrier. Must be the gear oil absorbing into my bloodstream...........