Removal of Single Speed Cog

[mmichel]

I'm not sure if single speed cog removal is similar to Rohloff (also a single rear cog setup) cog removal, but I'm guessing it is. My cog is seriously stuck, and I need to get it off. The way the Rohloff works is this. There is a special tool that locks the free wheel and has flats on it for a 24 mm wrench. Picture a cylinder with 4 prongs that engages the hub that normally spins when your cog spins backward. The 4 prongs hold the hub essentially, and then you use a chain whip to turn the cog counter clockwise to remove the cog. I essentially am leaning over the wheel with one hand on the 24 mm wrench (on the tool) and the other hand on the chain whip, but I can't get it off. I even put my wife (about 115 pounds) on the 18 inch long wrench while I got on the chain whip. I lifted her up, so it is stuck pretty good.

I have seen good mechanics pull a trick where they put some part of the wheel (cog or tool possibly?) in a vice such that the cog is down toward the vice. The mechanic then bear hugs the tire with both arms (huge moment arm length to help here) and then spins the wheel to loosen cog. I don't understand this trick because if you grab the cog with the vice, you would just "pedal backwards" with the freewheel by turning the tire. There must be a third something holding the freewheel to make this trick work.

Someone enlighten me please.

Matt

[markie]

One of these tools:

http://sheldonbrown.com/harris/tools/freewheel.html

goes in the vice for a SS hub with a freewheel. I have no idea how things with gears work.....

[mmichel]

Maybe I am being really dumb here. I will look again. I have the equivalent of the tools you showed. If you put that tool in the vice, you still have to turn the cog alone, not the wheel. There is still something missing here.

Matt

[BikerMiker]

The tool doesn't grab onto the cog, it grabs onto the freewheel part that allows you to turn the threads. Freewheels have the 'freewheel' mechanism built in (hence the name) and you remove them with the tool.

Put tool in vice. Fit freewheel in tool. Grab wheel and turn, hard, bracing yourself so you don't fall into something. Oh, having a good, solid vice is kind of a good idea.

There are a few different tools that fit different freewheels, but the four-pronger fits most.

It would be great if there was a place where you could take bike stuff if you don't know about it and they could show you and fix it for you. Oh, wait...

mike

[mmichel]

Thanks for the info. Actually, my Rohloff does not work that way. I guess they are different than a typical freewheel. In my case, the tool must be held in vice or by a 24 mm wrench and the cogs must be then spun counter clock wise by a chain wip. I can't use the grab the wheel trick I guess.

Thanks for all the help. The end of the story is, I continued to try with my chain whip (and my wife on the other end with the wrench). Eventually, I got her a cheater because I was lifting her. At that point, my chain whip bent as if I was Super Man bending a steel rod. I took it to Loren at the Bike Lane. It pained me to see how hard he was pulling with his big burly chain whip. It came loose. Whew. Not sure if anything is damaged yet, but am in process of doing so.

Unless it happened during the battle of breaking it loose, I can see my drive train problem. I'm chasing a tiny "tick" I can feel in my pedals that started midway through the SM100. One of the cog's teeth is bent along the skewer axis direction slightly. I must have thrown a rock into the unprotected portion of the cog while downhilling. Of course it could have happened while bending my chain whip, and I still have yet to find the problem.

Matt

[mmichel]

I realize I am mostly conversing with myself at this point, but here is the end of the story for those interested.

The Rohloff cog is reversible. I reversed it to a fresh side. I couldn't feel the "tick" but things were grinding everywhere. I've felt that before. I went back inside and measured the chain stretch. I measure it fairly regularly, so I expected it to be fine. The 0.75 side dropped straight through. Whoa. The 1.0 side then dropped straight through. Double whoa.

It appears I've had some rapid chain stretch or I have seriously neglected measuring it for a long while. The cog is hooked badly on the worn side. The chain has too much stretch to run on the fresh side.

I've got chainring, chain, and a cog on the way. I'm confident that will solve it. I'm embarrassed about not looking at the chain stretch first, but I am pleased that the problem is external to the gear hub which would have meant the hub going back to Germany for a repair.

Matt

[pepelkod]

The Rohloff cogs are notoriously hard to get off (search google for stories). I had a very similar experience. Bent my chain whip and actually broke a couple links in it trying to get my cog off. Finally got it off. I though I broke something because it snapped loose so suddenly.

You might want new seals when you put the cog on. (The seals mate to the cog for an oil tight fit according to Thomas (Rohloff USA)).

-D

EDIT:

If it ever needs it, the hub can be services by Rohloff USA in Berkley Calif. No need to send it to Germany.

[hophead]

I use one of these. 600 ft/lbs of torque works every time......

[mmichel]

Pepelkod,

I've learned a few other Rohloff tricks over the years. Here are mine. Have you got any others?

1. I don't like Rohloff Cables. I love their inner sleeves, but not the housings. I run the Nokon German made armored aluminum stuff. It works fantastic for a full suspension job. Any high quality cable works fine I've found.

2. I don't like Rohloff's tensioner. I've been using Surly's Singulator (just enough travel for a Truth frame). I think I just like the aestetics of it. Weight is saved as well (chain length and lack of second pulley).

3. I like Rohloff's front chain guide, but I switched eventually to trapping it between two rock guards in front. This works great as I ride at GW Forest and the Shed quite a bit (bounce the chainring off rocks occasionally).

4. The thumbscrew for the gear mech is designed to be captured. I've found that over the years, the "capturedness" of this screw was declining. Eventually I had a on-trail loss of the screw. Luckily I didn't throw the mech into the wheel. I had to go back and scour the trail for a half hour. Finally found it. I later swaged it with a tiny flat screw driver to flare it again to be quite "captive" again.

5. I changed my seals (cog side and non cog side) a year ago. At the time I didn't know about Cali.

6. Rohloff says don't lube cables. I call crap on that. I lube my twist shifter, my cables and housings, and the gear mech. Even with all that, I find that changing cables and sleeves every 1000 miles or so a great thing.

7. I have chased a few creaks into the hub, but they are all superficial. Generally it is the outmost interface with the bike (one inboard of the actual interface with the dropouts). A shot of teflon spray in there, quiets it all back down. Skewers have to be on TIGHT to avoid creaking with my set up.

8. Rohloff says 8-speed or 9 chains w/ 8-speeed preferred (strength). I go 9-speed because the chainrings up front these days seem to be better suited for 9-speed even when Salsa says they are good for 8-speed or 9-speed.

Let me know if you have any lessons learned. I'm always interested.

Matt

[pepelkod]

Pepelkod,

I've learned a few other Rohloff tricks over the years. Here are mine. Have you got any others?

1. I don't like Rohloff Cables. I love their inner sleeves, but not the housings. I run the Nokon German made armored aluminum stuff. It works fantastic for a full suspension job. Any high quality cable works fine I've found.

I just bought a bunch of bulk Jagwire brake cable. I was going to try that. The cables that came with have been working just fine though. My biggest prob with shifting is that my sweaty hands can't always turn the shifter, but full fingered gloves have solved that problem. (The sweat was so bad I could barely hold onto the handlebars some races.)

2. I don't like Rohloff's tensioner. I've been using Surly's Singulator (just enough travel for a Truth frame). I think I just like the aestetics of it. Weight is saved as well (chain length and lack of second pulley).

Im running a Paul Melvin. I like it ok but it cost as much as an XT der. There was an "incident" with the Rohloff tensioner and I dare say it was totaled...along with my hanger.
I can't run a single cog tensioner right now as the Titus has too much driveline extension. I would like to get a Lenz Sport Leviathon (29) with the concentric suspension. The chain length does not change with suspension movement.


3. I like Rohloff's front chain guide, but I switched eventually to trapping it between two rock guards in front. This works great as I ride at GW Forest and the Shed quite a bit (bounce the chainring off rocks occasionally).

I had a bash guard on the inside and no chain guide and it was fine for a long time (very tight Melvin). But then the Melvin started acting up (not returning quick enough) and I lost my chain a few times during races (check the CM crit video for me crying as I try to engage my chain), so I went back to a front der with the set screws all the way in. It looks like junk. Maybe I will try dual bash guards. What size ring are you running and what bashguards and lastly, where did you get them? My cog/chainring combo leaves me with only a 36t in front and there are few guards that will fit. Plus I would need some extra long chainring bolts. Ceccorulli, James and I talked at some length about that subject.


4. The thumbscrew for the gear mech is designed to be captured. I've found that over the years, the "capturedness" of this screw was declining. Eventually I had a on-trail loss of the screw. Luckily I didn't throw the mech into the wheel. I had to go back and scour the trail for a half hour. Finally found it. I later swaged it with a tiny flat screw driver to flare it again to be quite "captive" again.

5. I changed my seals (cog side and non cog side) a year ago. At the time I didn't know about Cali.

6. Rohloff says don't lube cables. I call crap on that. I lube my twist shifter, my cables and housings, and the gear mech. Even with all that, I find that changing cables and sleeves every 1000 miles or so a great thing.

7. I have chased a few creaks into the hub, but they are all superficial. Generally it is the outmost interface with the bike (one inboard of the actual interface with the dropouts). A shot of teflon spray in there, quiets it all back down. Skewers have to be on TIGHT to avoid creaking with my set up.

Mmm. Nothing on mine yet. I got oil leaks at first. Now I keep it upright.

8. Rohloff says 8-speed or 9 chains w/ 8-speeed preferred (strength). I go 9-speed because the chainrings up front these days seem to be better suited for 9-speed even when Salsa says they are good for 8-speed or 9-speed.

8. I tried a SS chain. I had to put a washer in my tensioner so the chain would fit. I went back to 8 speed chains.


Let me know if you have any lessons learned. I'm always interested.

Matt

Keep your hub upright. If it ever decides to leak, you don't want that oil on the brake pads.

Good info overall. I will check my thumbscrew.

-D

[mmichel]

Pepelkod,

Full finger gloves are essential in summer. I agree there, and that goes for any moutain biking, not just Rohloff.

I started with a 42 x 17 (basically just like a 3 x 9 with 44 x 12 and 22 x 34). That was when I had the Rohloff front guide. This worked very well and was legit on Rohloff's rules. But it wasn't "cool".

I now have a 36 x 16. I like the log and rock clearance of the 36T. It is just barely too high a ratio according to Rohloff. I break this rule because of the efficiency thing. Did you know the first 7 gears are about 4% less efficient than the last 7 (according to some sources). I try to stay in 8-14, so the 36 X 16 helps me do that. (Conventional drive trains are also less efficient in super easy gear combo's.) The problem with the 36 x 16 was the bash guards. I had to go custom on both of these. My inner bash guard is an outboard 42T that I ground the teeth off of. If you don't know, the pilot diameter for a center ring is not the same as for the outboard ring. I also had to grind the pilot out slightly (fine dremmel work). The outboard I bought a Salsa outboard bash guard for a 42 - 44 T and then ground it down to fit a 36 T. If you ever notice my outboard chain guard has a cam shape as it meets the crank, that's why.

Only an insane person who really thought his bike would look 5% cooler with bash guards would go through all that, but I have to admit that I really dig my current set up. My bike has a very "single speed" look to it with single pully tensioner and bashguards (and small ring up front).

Your Lenz Sport Leviathon idea sounds like the bomb.

Matt