# Rolhoff on a Lenz Revelation



## Berkeley Mike (Jan 13, 2004)

My son and I have this on spec from our local shop where he had a chance to grommet last summer around hand-built wheels and these hubs. He is unencumbered by prejudices against the Rolhoff and has faith in them.
2003 Lenz Revelation with a Rolhoff hub:
FSA Carbon Cranks with 7075/T6 38T chainring
Hugi front hub with hand laced to Mavic 317 disc wheels
Magura Marta brakes with carbon levers and 170mm rotors
Marzochi Bomber mrathon SL front shock
Fox float RP3 rear shock

He is a pretty decent rider, and a fine all-around athlete, in his second year of NorCal High School racing. He's a good judge of riders and appreciates bikes so I listen to him. He's ridden the Roly Lenz around our canyon a lot and loves it. I took him to Tamarancho last week and he just flew and raved about the way it handled but he has ridden no other dual suspended bikes. His experience is limited to his Rockhopper Disc, his SS M2, and his Medici Pro Strada Road bike. So I took it out.

I could not get the height in the seat from the Raceface seatpost but it was still rideable. Right away I felt the extra friction of the lower gears. I have never been a fan of GripShift. My favorite system is XTR with Dual Control levers. I have always preferred Rapidfire but arthritis at the base of my thumb makes the levers much nicer. I didn't like the stiffness of the GripShift. It was far less fluid than other GripShifts I have ridden and it was hard on my hands with my arthritis. Bad hands aside, it is a lot stiffer than I would like.

Apart from the friction of the lower gears there were shifts that seemed absolutely seamless exceeding even the very best-timed Rapidfire shift. It didn't take long to find the weirdness in the 7-8 area, though. It took a while to know where it was and accommodate it. The friction seemed to disappear in the higher range. Further, being accustomed to mechanical discs, I nearly vaulted over the bars the first time I grabbed the Martas.

I wasn't able to really challenge the handling of the bike as much as I would have liked due to the low seat. Right off the bat I could feel that the Lenz, at 26.4 lbs., WAS lighter than my Stumpjumper Pro. It was a full pound and a nice difference. I was unimpressed with various positions of the Fox RP3 but it was nice overall. The Marzochi was very smooth, though a little bouncy for me out of the saddle. It matched up well with the Fox. The first time I tried to bunnyhop a cattle guard I forgot the added weight of the Rolhoff hub and did a nose-high jump. My next attempt was dead even and I discovered that the weight of the hub balanced nicely that nose-heaviness we have come to forget caused by the front shock. Now I understood why my son liked the way the bike handled; it had a balance not seen in many modern bikes unless one went back to a fully rigid set-up.

I gave this feedback to the builder/owner of this bike and he identified the 7-8 glitch describing the usage of another gear to make the transition between the upper and lower gears ranges. He also suggested that this glitch becomes less and issue as experience with the hub grows. As to the stiffness of the Grip Shift he thought a new set of cables might be warranted.

To be fair this bike, in great condition, has seen remarkably little use. It's last ride was a nasty gritty muddy affair and the bike was "cleaned." and then sat again. When we got it I cleaned it and my son rode it and he said it felt stiff and halting. I took it back to the mechanic and he and I injected grease into the nipple which handled both the BB and the lower pivot. It took a lot and what was pressed out was dirty and thick. Taking that as an example of the lubricant condition of the bike we proceeded to use the bike and attend to it's needs as we experienced them. Now, with the exception of the "cables" it is a fluid machine. A very interesting bike. I wish I had a seatpost long enough so I could really ride it but I have a good feeling about this thing..


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## Berkeley Mike (Jan 13, 2004)

*I had to eat reheated Turkey and stuff*

then during Planet of the Apes I wrote the rest of the thought.

Burp!

Skewz please.:thumbsup:


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## krolik (Jun 9, 2006)

Nice report
How do you manage to run it without any type of tensioner??


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## Berkeley Mike (Jan 13, 2004)

*Like this*

drops are interchangeable.


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## krolik (Jun 9, 2006)

Nice feature but what about the chain growth when suspension compresses?? What takes up the loose chain? Or is there none in that particular frame?


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## Berkeley Mike (Jan 13, 2004)

*Magic*

or it hasn't been a problem so far.


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## rockyuphill (Nov 28, 2004)

Looks like a concentric BB pivot on the swingarm.

The new Revelation frames don't have a concentric pivot.


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## Berkeley Mike (Jan 13, 2004)

*The pivot on this '03*

actually wraps around the outside of the BB just off center toward the bottom. Kinda cool. I wonder why they changed it?


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## rockyuphill (Nov 28, 2004)

It is harder to keep the pivot bearings clean and more hassle to service the BB pivot. Kona, Dean and Cove Bikes still have FS bikes with concentric pivots. I use a Kona A for my Rohloff bike.


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## krolik (Jun 9, 2006)

Ah, all obvious now. 
I will have 20mm chaingrowth on the new nomad to take care of. not too much but still requires a tensioner.


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## bsdc (May 1, 2006)

Very nice bike.


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## Berkeley Mike (Jan 13, 2004)

*Ah, concentric pivot. Now I get it.*

But how is it harder to keep clean? Seems like you just inject grease through the nipple and you are done. I wish there were more grease nipples in bike designs. Servicing the BB does look a bit of a bother but the ease of refreshing lubrication means it is going to happen less often.

As you have had experience with these, though, I have to appreciate your input.:thumbsup:


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## rockyuphill (Nov 28, 2004)

The BB pivot bearings have a big seal area and they are right down in the mud and gunk, so they are exposed to more mud/water infiltration than a smaller diameter swingarm bearing. If the Lenz bike has grease nipples for the pivot bearings that's an advantage.


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## Berkeley Mike (Jan 13, 2004)

*Sounds like something to keep an eye on*

I will also ask the mechanic about the history of such things. Thanks for the heads up.


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## Speedub.Nate (Dec 31, 2003)

I'm not a fan of the ride characteristics of the BB-centric pivot, but a light bike is a light bike and Thomas of Rohloff USA has a Revelation with V's down to about 22 pounds when I first met him back in '01 or so. Of course he had some fairly light components on it, but it was perfectly rideable.


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## rockyuphill (Nov 28, 2004)

I have found the Kona A with a 32:13 gear keeps the pedal induced bob to a minimum, but I am happy to have a Fox RP3 with ProPedal. If you were running a bigger front ring, like a 44T, the suspension movement would be worse with pedal input.


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## Berkeley Mike (Jan 13, 2004)

*I neglected to list the rear cog.*

38:16= 2.38
where the 32:13 = 2.46

I'm not sure what that has to do with pedal bob. Thoughts?


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## rockyuphill (Nov 28, 2004)

With a concentric BB pivot, the larger the chainring, the more leverage is applied to the chain and swingarm to try to wrap the swingarm up around the BB pivot when you apply pressure to the pedals. A 44T chainring has more leverage than a 32T because the chain is further from the spindle, and the lever effectively formed between the spindle and the chain is longer.


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## Berkeley Mike (Jan 13, 2004)

*Doesn't add up for me*

in any intuitive way though you may be right. I expect that downward force is really the prevailing cause of bob; blocky quad-heavy pedaling style or hammering out of the saddle. Spinning nice circles would develop no bob. Torque to the pedal through a ratio against an equal resistance, all things being equal or very close in this case, deliver the same power to the tire patch. I just don't see how that would effect bob.

You may be right as I say, but it doesn't make sense to me.


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## bsdc (May 1, 2006)

Berkeley Mike said:


> in any intuitive way though you may be right. I expect that downward force is really the prevailing cause of bob; blocky quad-heavy pedaling style or hammering out of the saddle. Spinning nice circles would develop no bob. Torque to the pedal through a ratio against an equal resistance, all things being equal or very close in this case, deliver the same power to the tire patch. I just don't see how that would effect bob.
> 
> You may be right as I say, but it doesn't make sense to me.


On a smooth trail with with a really good spinner, you are mostly right, but in the real world where we don't spin smoothly, and are constantly varying our efforts on ever changing, rough terrain, pedal induced bob is an issue for a concentric BB pivot. Some of that is reduced with your RP3 in one of the propedal modes.

Don't get me wrong. It's not a condemnation of your bike. Your bike is awesome. I love the idea a FS Rohloff setup without a chain tensioner. I'd like to get a Milk Money/Revelation like yours some day.


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## rockyuphill (Nov 28, 2004)

Think of it this way, you have a lever created by the radius of the chainring that is trying to rotate the swingarm up and around the BB pivot. The shock resists this force. A bigger diameter chainring gives you a longer lever to apply force to. But all pedal input applies that leverage through the chain. It becomes more sensitive to where you put power into the cranks, especially if you are out of the saddle climbing and applying body weight to the pedals as well.

With a decent shock and smaller diameter chainring the bob is quite tolerable.


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## Berkeley Mike (Jan 13, 2004)

*It looks like a good description of what you intend.*

I have a fair bit of math, science, and physics in my days so I follow you. Yet it still takes a given amount of power to move a wheel and, ratios being equal (an assumption for this model, okay?) I don't see where a larger front chainring makes any difference at all. Watts in, watts out.

At the same time I have read some pretty exhaustive technical descriptions about the placement of pivots, conventional wisdom, and advertising which challenge lots of thoughts about bob and brake jack. So I'm a tough sell on theories that don't measure up to my personal experience (and biases) and clear mechanical and measurable analysis.

I will keep this in mind and discuss it with other mechanics over beers. Thanks for you thoughts and time; it is not wasted.

Now crank arm length.........


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## Berkeley Mike (Jan 13, 2004)

*Talked to my mech using the bike.*

He described how chain angle as dictated by the size of the front chainring can effectively lift the rear wheel. Also described how this is not a problem with a BB-centric pivot as the rotation of the swingarm doesn't change the distance between the gears. He had enough bikes to show me what happens when pivot locations are changed and why feedback into the pedals happens when those distances change. Some get longer and then shorter, or shorter and shorter, as the travel increases which makes things really goofy as you go over a bump.

He also said that the Rolhoff hub asks for a certain gear ratio and a minimum gear size for the rear for stress reason and practical consequent gear ranges.

Anyhow, now Rocky's description makes sense to me. I just had to really see it explained on a number of bikes.


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## Wish I Were Riding (Jan 30, 2004)

bsdc said:


> I'd like to get a Milk Money/Revelation like yours some day.


Amen brother. Me too, me too...


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## Berkeley Mike (Jan 13, 2004)

*Full length cables*

We went to full length cables a few weeks ago. Buttery smooth.


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