Community > Rohloff Internal Hub Gears
sprocket reversing problem anyone?
redcogs:
my sprocket needs reversing, because of wear (it has a 'wave' type appearance). So, i purchased the said special tool, which fits a treat.
Problem is that freeing the sprocket seems to require a great deal of force - more than i have been prepared to apply so far - i'm a bit worried about damaging any of the hubgear internals... the 'chainwhip' that i'm using seems to be straining to near its breaking point (it is also new) so i have given up (so far).
Question is, has anyone else experienced this prob? Any tips? Should i use a hammer on the cog?
i'm a bit miffed at my inability to perform what seems to be a simple operation.[:(]
stutho:
I along with others have had problems removing the sprocket. Even if the sprocket is copper greased it still need a VERY large amount of torque to remove it. I snapped the pin on my first chain whip removing a copper greased sprocket. After buying a better and LONGER chain whip I got it off.
Before you start muscling away don't forget to do a reality check.
* Is the chain whip fully engaged
* Is the chain whip turning in the correct direction (Anticlockwise)
* Can the 'special tool' slip? (Make sure the Quick release / axle bolts are holding the 'tool' firmly in place.)
* Is the shifting spanner fully engaged and tight on the 'tool' and is the spanner the correct way up
* **IMPORTANRT** when the Sprocket finally comes free am I going to hurt my hands when the spanner meets the chain whip
* Check again that the chain whip is turning anticlockwise and the 'tool' clockwise - it is easy to get this wrong!
If you are in any doubt about the quality of you chain whip I would replace it with a nice BIG one - If I had of done this I wouldn't of marked the hub when my first tool broke.
When you eventually do get the sprocket off remember to copper grease the threads before putting it back on.
Incidentally how many miles did you get from side 1 of the sprocket?
AndyB:
Hi Redcogs,
Don't worry, it should be simple to remove the sprocket(with the correct tools), I'll try and talk you through it...please accept my apologies in advance, if the first part is not applicable to you but I have presumed that this information may also be of interest to others too!
It is best if you rehearse all the operations in your head, before "going for it!"
The first thing to realise is that, if you have ever used a cassette remover and chain whip to remove a cassette, you will be tightening up the sprocket on the Rohloff hub, if you attempt to use the chain whip in the same direction as you would with a cassette hub. If you have done this and used enough force to almost snap the chain whip, then you now have the sprocket on really, really tight!
The reversal of the sprocket should be planned, in advance of needing to do it...given the massive service life of the sprocket, the need to reverse it, shouldn't be a thing that takes you by surprise. I say this because you will require access to a large vice, which is mounted securely to a workbench.
Remove the QR skewer, locate the sprocket removal tool's lugs into the slots on the hub and replace the QR skewer...this is important to maintain secure location. Tighten the QR fully and then back it off a quarter of a turn.
Now locate the flats of the tool in the jaws of the vice and clamp the tool securely.
Take the chain whip and wrap it carefully around the sprocket and use its leverage to turn the sprocket ANTI CLOCKWISE.(when viewed from the sprocket towards the hub)This may take considerable force.
NOTE THAT BECAUSE THE HUB IS INVERTED (SPROCKET SIDE DOWN)THIS WILL MEAN LEVERING THE CHAIN WHIP CLOCKWISE, AS YOU SEE IT, WHEN LOOKING FROM ABOVE...once the sprocket moves, remember that you have the QR skewer locking the tool on and remove it (that's why I said you must back it off a quarter of a turn.)
I hope that this is clear...if it is not, please re-read what I've written and if it still does not make sense...please contact me.
All the best,
Andy B. (Thorn's designer)
quote:Originally posted by redcogs
my sprocket needs reversing, because of wear (it has a 'wave' type appearance). So, i purchased the said special tool, which fits a treat.
Problem is that freeing the sprocket seems to require a great deal of force - more than i have been prepared to apply so far - i'm a bit worried about damaging any of the hubgear internals... the 'chainwhip' that i'm using seems to be straining to near its breaking point (it is also new) so i have given up (so far).
Question is, has anyone else experienced this prob? Any tips? Should i use a hammer on the cog?
i'm a bit miffed at my inability to perform what seems to be a simple operation.[:(]
stutho:
Andy,
quote:remember that you have the QR skewer locking the tool on and remove it (that's why I said you must back it off a quarter of a turn.)
Unless the design of the tool has changed, this info may not be correct. With my Rohloff tool it can be left attached to the wheel through all stages of removing the sprocket (i.e. the sprocket fits over the tool.
See page 90 of the sevice handbook
redcogs:
Thanks for the advice/help AndyB, i'll let people know when i've completed the task.
Sorry Stutho, i can't answer accurately the question about miles achieved on the cog - i got my Rohloff pre owned from Germany. However, i can say that at least 6000 (faultless) miles have been clocked since ownership came to me. [:)] Rohloffs are great.
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