Thorn Cycles Forum

Community => Rohloff Internal Hub Gears => Topic started by: redcogs on August 16, 2006, 04:35:16 PM

Title: sprocket reversing problem anyone?
Post by: redcogs on August 16, 2006, 04:35:16 PM
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.[:(]
Title: Re: sprocket reversing problem anyone?
Post by: stutho on August 17, 2006, 07:51:49 AM
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.


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?
Title: Re: sprocket reversing problem anyone?
Post by: AndyB on August 17, 2006, 08:25:27 AM
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.[:(]

Title: Re: sprocket reversing problem anyone?
Post by: stutho on August 17, 2006, 08:41:13 AM
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
Title: Re: sprocket reversing problem anyone?
Post by: redcogs on August 17, 2006, 08:50:06 AM
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.
Title: Re: sprocket reversing problem anyone?
Post by: AndyB on August 17, 2006, 10:53:43 AM
Hi Stutho, you are quite correct...Rohloff have made the tool so that the sprocket will pass over it...feeling a bit silly, Andy B.

quote:
Originally posted by 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

Title: Re: sprocket reversing problem anyone?
Post by: graham on August 20, 2006, 05:02:10 PM
After I bent my cheapo chain whip trying to do mine for the first time, I gave up and took the wheel, tool and photocopy of the instructions to my local bike shop on the assumption they'd have a decent chain whip. The nice man there did it in less than 5 minutes and charged me two quid. A lot less than buying a decent chain whip.
The second one I did, I managed using my own chain whip. But I now know I've got backup if I need it.
Title: Re: sprocket reversing problem anyone?
Post by: redcogs on September 06, 2006, 08:18:21 PM
Hi.  Reversed the sprocket myself yesterday using the benchvice method recommended by AndyB.  An easy job in the event.  Doing the job seems to have made a difference to gearchanging as well, it all feels a bit more 'crisp', not that it felt loose previously.. its just that, whenever i perform maintainance, even that which involves fairly small scale adjustments, i tend to feel that the cycling experience is enhanced thereafter.

Probably all in the mind.

regards all. [:)]
Title: Re: sprocket reversing problem anyone?
Post by: daviddd55 on April 20, 2007, 10:07:11 PM
being a novice with Rohloffs, I'm wondering if the chain whip is the same as the deralleur one?
Title: Re: sprocket reversing problem anyone?
Post by: stutho on April 21, 2007, 08:58:46 PM
Yes it is but you will need a quality tool - I broke my first one
Title: Re: sprocket reversing problem anyone?
Post by: daviddd55 on December 11, 2007, 12:37:23 AM
...am i right in thinking that by taking the wheel to any decent  bikeshop I won't need any 'special tools'? Or is there a specific Rohloff / Thorn tool required?
Title: Re: sprocket reversing problem anyone?
Post by: PeLu on December 11, 2007, 03:35:15 PM
Or is there a specific Rohloff / Thorn tool required?
It is the Rohloff tool fro removing the sprocket. This is a Rohloff special.
Title: Re: sprocket reversing problem anyone?
Post by: daviddd55 on January 11, 2008, 02:46:15 AM
update - I took the bike to St Kilda Cycles in Melbourne and got the sprockets and chain replaced (6000km) - with a new chain the rear sprocket was jumping (it wasn't ever turned around). The guy there broike a whip and almost did his back in by the sound of the cursing. Cost me $199 (80 QUID) but glad it's done now. I may need to do this all over again as I have another 14000 km (god knows where ?!) to go yet around Oz. I arrived in Canberra yesterday - nice place.
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 01, 2008, 11:33:53 AM
Quote
The nice man there did it in less than 5 minutes and charged me two quid.

Quote
The guy there broke a whip and almost did his back in by the sound of the cursing. Cost me $199 (80 QUID)

£80 !!! Did I miss something?  Did he throw in a new wheel or something?  That's the same cost as a new sprocket, removal tool, new chainwhip, new vice and a few beers to celebrate completing the task
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 04, 2008, 12:56:09 PM
If the sprocket spins off anti-clockwise, what stops it from spinning off under load from the pedals?
Title: Re: sprocket reversing problem anyone?
Post by: daviddd55 on February 12, 2008, 06:53:04 AM
£80 !!! Did I miss something?  Did he throw in a new wheel or something?  That's the same cost as a new sprocket, removal tool, new chainwhip, new vice and a few beers to celebrate completing the task
:-\ no that's correct Freddered - is that that expensive? I expected to pay more for Rohloff stuff, and even more in Oz, and he did spend 2 hours fitting it (and a broken chain whip and nearly broke his back in the process!!!). I've no idea what UK prices are like for Rohloff stuff.
Title: Re: sprocket reversing problem anyone?
Post by: stutho on February 12, 2008, 11:02:23 AM
Freddered:
If the sprocket spins off anti-clockwise, what stops it from spinning off under load from the pedals?
Um the chain pressure will tighten the sprocket.  If you were to hold the wheel and press on the pedals then you will apply a clockwise force to the sprocket relative to the wheel.  (Note it is possible, in theory, to unscrew the sprocket while freewheeling).  The reason that there might be confusion is that when you are removing a cluster from a derailer set up you need to loosen a lock ring to do this you apply  a clockwise pressure to the cluster (to stop the freewheel from rotating) and an anticlockwise pressure to the lock ring  (kind of the opposite of the Rohloff). 

Davidd55
Quote
Cost me $199 (80 QUID)
There is no easy way to say this David but you were ripped off.  There is a special tool for removing the sprocket but it isn't expensive - you also need a quality, workshop, chain whip (note I have now personally snapped two lesser chain whips!).  A good bike shop, that knows which way to remove a Rohloff sprocket, should get the job done easily in 5 minutes.  I would be expecting to pay £10 absolute max!

Stutho

 





 
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 12, 2008, 11:18:57 PM
Thanks Stutho

Durrr, I was a bit thick and now I have remembered which side my chainring is on it's obvious.

Re.  £80 for sprocket removal.  I think you bought the LBS a new chainwhip.
Unless he bought the tool himself I would expect my LBS to say "forget it, it only tool a minute" (as long as I looked like I was going to buy something from his shop).

It's like a Car Tyre garage removing a wheel to quickly check if your wheel is damaged isn't it?  I'd tell them to stick it up their ar*e if they charged me £80.
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 22, 2008, 07:45:00 PM
I bought the Sprocket removal tool and let  "Just Bikes" of Andover use it to remove sprocket.  I watched him do it, it took less than 30 seconds (after some grunting) and cost me £4 (their min labour charge) so I won't bother with a chain whip and vice because it's only likely to happen every couple of years.

Note.  I printed off Andy B's instructions for my LBS.  It's worth doing because LBS didn't really believe it should spin off anti-clockwise until I showed him instructions.
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 23, 2008, 07:42:41 PM
I just found loads of my Rohloff Oil was on the Garage floor this morning.

Does the Sprocket form an oil-seal?  The sprocket was loose, waiting to be flipped today.  I have an oil-change kit ready and waiting but I'm reluctant to put new Oil in if it's going to leak out again.

Can removing the sprocket break an important seal?
Title: Re: sprocket reversing problem anyone?
Post by: Cake on February 23, 2008, 07:59:50 PM
Did you leave the wheel upright overnight Freddered?  I know you're not meant to lie the bike on its side for any great period of time for that reason....  I'm sure you know that anyway!
Title: Re: sprocket reversing problem anyone?
Post by: stutho on February 24, 2008, 01:31:14 AM
Hi freddered,

Quote
Does the Sprocket form an oil-seal?

YES!  Once the sprocket is off you need to keep the wheel on the LHS.
 If you have lost significant oil then I think an oil change would be a good idea, as soon as you have the sprocket back on (donít forget the copper grease).   Rohloff claim that you can't loose enough oil from the g'box to do any damage, but on the other hand why push the envelope  when you have an oil change kit sitting on the shelf.

All the best

stutho
Title: Re: sprocket reversing problem anyone?
Post by: freddered on February 24, 2008, 02:04:16 PM
Thanks Stutho, that's reassuring.

I'll go out for a few miles to tighten the sprocket up and then do an Oil-change.
Title: Re: sprocket reversing problem anyone?
Post by: daviddd55 on June 07, 2008, 02:45:13 PM
Thanks Stutho

Durrr, I was a bit thick and now I have remembered which side my chainring is on it's obvious.

Re.  £80 for sprocket removal.  I think you bought the LBS a new chainwhip.
Unless he bought the tool himself I would expect my LBS to say "forget it, it only tool a minute" (as long as I looked like I was going to buy something from his shop).

It's like a Car Tyre garage removing a wheel to quickly check if your wheel is damaged isn't it?  I'd tell them to stick it up their ar*e if they charged me £80.
No, no, no - 80 quid was for the whole setup - chainring, sprocket and chain!! And fitting!!
Title: Re: sprocket reversing problem anyone?
Post by: stutho on June 09, 2008, 05:21:18 PM
That not too bad... but I would still recommend doing it all at home and saving a few £££.
Title: Re: sprocket reversing problem anyone?
Post by: ALMEIDA on July 16, 2008, 06:09:52 PM
Hi,

please have a look on the following link. Believe me, it's a pretty good instruction.

http://forums.mtbr.com/showthread.php?t=250041 (http://forums.mtbr.com/showthread.php?t=250041)

ALMEIDA

Title: Re: sprocket reversing problem anyone?
Post by: jawj on December 03, 2008, 07:22:23 PM
Phew, just got my sprocket off! Blimey that required some heaving and hoing.

...you will require access to a large vice, which is mounted securely to a workbench.

Yup, Andy might be right there. I had to zip tie a pole to my chain whip and then use this hybrid tool along with a massive adjustable spanner in the manner of a rowing machine whilst sitting on the floor to free the sprocket. Good times!

(Crawls away with spinal injuries to fetch the GT85 to mop up more spilled Rohloff oil on carpet...)
Title: Re: sprocket reversing problem anyone?
Post by: redcogs on December 09, 2008, 10:02:49 PM
Hi. A recent issue arose on replacing my socket with a new one, and i thought that people ought to be aware.

i had reversed my socket quite some time ago because the teeth had become quite worn on one side.  Reversing it corrected the problem, and obviously extended the life of the item significantly.

However, be warned..  If you allow too much time to elapse prior to replacing the socket with a totally new one, you could well face the same problem as me - ie, the cog teeth had become so worn that they were very weakened, and the chainwhip, when applied with the necessary force to remove the cog, began to snap off the teeth of the cog one at a time. 

What was almost a disaster was rescued when the cog did finally loosen before the cog was irretrievably weakened by tooth loss thus preventing the use of a chain whip.

i would add that this near catastrophe was entirely my own doing - i had definitely waited for far too long before fitting a new cog, but its the sort of job that is easy to overlook, especially because we are so unused to having to perform any maintenance thanks to Rohloff and Thorn!

So, i would recommend keeping a pretty close eye on the state of your rear cog once you have reversed it.  Better safe than sorry.
Title: Re: sprocket reversing problem anyone?
Post by: jawj on December 10, 2008, 12:21:35 AM
That's a good bit of advice, Redcogs, glad you managed to remove it before all the teeth gave up - that would have been a nightmare!

It leads me on to an almost related subject...

The following may cause a little controversy as I've read previous threads on here about people comparing how many tens of thousands of miles they can squeeze out of their chain.

To those people I say: ditch your chain before it wears out!

I'm pretty certain if I'd followed that advice and do what I normally do and replace my chain very regularly (4-5 months, though this does of course depend on your mileage and the conditions) then I wouldn't have had to reverse my sprocket for a jolly long time yet. I'm aware too of the threads in this forum about how a Rohloff hub can actually save you money in its lifetime (tenuous...) but I use a Speedhub cos it's bombproof and there's a lot less cleaning of solid black crud off jockey wheels to do (you all know what I'm talking about!) I service and clean enough peoples' cacky bikes every day that I'm very put off doing any maintenance to my own bikes. The most shameful example of this is a chain of mine that was only several months old that I just didn't fancy cleaning: it got replaced...

Terrible! I know! But it stops sprockets wearing out...!
Title: Re: sprocket reversing problem anyone?
Post by: stutho on December 10, 2008, 12:50:17 PM
Redcogs,

How much mileage did you get out of the sprocket, before you tried to remove it.  This is not a criticism - I am just mealy curious.  I recently reversed my sprocket after 12000 (mainly road) miles on one chain.  There seamed to be very little wear  on the sprocket, the chain ring  however was badly worn (I doubt that I will get another 12000 miles out of the other side)

jawj,

I have to say I disagree with you, you can run much higher mileage per a chain with a Rohloff. A chain on a good single sprocket chain  run experiences FAR less loading than a derailer set up - no lateral or twisting loads.  With a derailer everything has to be keep  in a tight tolerance else you wear out an expensive cluster - again not a problem with  the Rohloff so you can run a chain far beyond the normal 1/16" in 12 rule.  If I had changed the chain as often as on my derailer set up then I would be looking at having bought at least another 3  chains at £15  = £45 that I haven't spent.  By the time I  do need to change my chain ring and my sprocket I should of save ~£90 in new chains alone which more than covers a new sprocket and chain ring 
 

   
Title: Re: sprocket reversing problem anyone?
Post by: jawj on December 11, 2008, 09:39:35 PM
What a strange mix of experiences we seem to have. I too, Redcogs, would like to know how many miles you've had out of your sprocket. I reckon I've done about 8,000 miles, though I must admit the sprocket is not completely worn out on that side. The bike's getting a new chainring and cranks so I thought I'd give the sprocket a fresh face to work with as well. (Not that there's anything wrong with the old chainring either, it's just moving onto pastures new on a different bike.)

I am intrigued to know what chain cleaning regime/methods you follow, Stu, to get 12,000 miles out of a chain. I'm impressed! I've done less miles and changed my chain a couple of times and yet my sprocket was noticeably, but as I say not completely, worn. The chainring, on the other hand, doesn't seem too badly worn at all, certainly less than the sprocket.

Ooh er, there's some spooky stuff going on here...
Title: Re: sprocket reversing problem anyone?
Post by: pdamm on December 13, 2008, 01:30:53 AM
I guess what Iíd really like to know is how long I can leave a chain on for until it becomes a problem.  Having the teeth on the sprocket break off when you are trying to remove the sprocket is certainly a problem! 

I recently asked Rohloff that question and was told that the standard limits that apply to derailleur equipped bicycles also apply here.  I tried debating the point with them but go nowhere.  I also didnít get a lot of reasoned response to my arguments so I suspect the person I was dealing with was not all that technical.  The experience of many members of this forum contradicts the advice I received from Rohloff.  What I was told however was that since we need to use a chain whip to remove the sprocket, a worn sprocket risks the chain whip not being able to grip the sprocket properly.  It seems that Redcogs experience is that the teeth may break off before the chain whip slips. 

I must admit I have been trying to work out how to get a sprocket off without a chain whip in case I find myself in the same situation as Redcogs but end up breaking all the teeth!

This rider had a different sort of problem after 18,000 km when the chain started to slip on the sprocket.

http://www.crazyguyonabike.com/doc/page/?o=3Tzut&page_id=74593&v=5u

I am up to ~21,500 km on my Raven Tour.  I reversed the sprocket at about 9,800 km and replaced the chain.  Since then my chain has done ~ 11,700 happy km and has elongated by 3/16 inch over 12 links (i.e., 3 times the recommended limit for derailleur equipped bikes).  The sprocket looks ok but my sprocket ware indicating tool (from Rohloff) says it is way past it.  I am not a mechanical engineer and for a part time handyman, experience has taught me that I am much better off sticking to my day job.  My gut feel is that it is ok to keep going for a while but how long? Ė is it ok for it to be worn by 4/16ís or 5/16ths I am not sure.

For those who are interested I oil my chain with White Lightning after about 4 to 5 hours of riding.  I have never cleaned my chain.  It is a bit mucky but the WL falls off after a while so the muck levels have long since stabilised.  I am sure there are better ways to look after a chain but this is what I do.

Does anybody else have any measurements for how much their chain had elongated when they finally retired it Ė and how easy was it to remove the sprocket?

If enough of us can contribute some measurements, over time we should be able to come up with some sort of recommendation for how much a chain can elongate before it is time to change the chain and reverse the sprocket.

Peter
Title: Re: sprocket reversing problem anyone?
Post by: stutho on December 15, 2008, 12:32:41 AM
Just in from the garage after measuring my old chain - yet to find it way to the bin!  The result was a little of a surprise.  The extension was a little over 1/8" say 5/64" in 12 link (a bit more than 1%).  It is cold and I only took the one measurement (I will try again tomorrow to confirm).  I was expecting it to be more.

I ride a 42T/16T  The Chain ring is Blackspire  Downhill which like I said previous is very worn on one face after 12,000.  I will be very happy if I get the other side to 10,000miles.  The Spur gear is looking in remarkably good condition it is NOT hooked but the end of the teeth are slightly chamfered.

The chain was an SRAM PC68 with a powerlink and my lube of choice Rohloff (I sometimes stray).  I can never make my mind up on chain cleaning.  Sometimes I shake the chain up in white spirit followed by shaking it up in a 50% dilute mix of mucoff (I am sure  any modern degrease would work)  followed by a rinsing in water and drying in the oven - I have an understanding Wife.  I re-oil the chain while it is still warm so that I get the maximum penetration. However I am not convinced the all this effort is worth it  - I also think it promotes rusting,  the PC68 is plated on a standard chain the risk of rust would probably out way any gain of a clean chain.  So... I sometime think that just wiping the chain down (very thoroughly) and re-oiling  is just as affective, recently this method has being getting my vote more and more.   I use baby wipes to do the wiping down. 

I am going to say again that nearly all my miles are on road,  offroader would get less mileage.  When the chain ring gives up the ghost (hopefully in 3 years time) then I am going to switch the lot out inc the spur gear.  Ideally I will be getting stainless steal chainring, Surly make them but only in 5 bolt - typically I got a 4 bolt spider - but I digress.

All the best

Stutho       
Title: Re: sprocket reversing problem anyone?
Post by: davefife on January 26, 2009, 07:55:37 PM
I just "reversed" this afternoon - 9,000 miles.  All was so easy :D  Especially after some the anxiety inducing tales told previously.  I used the by the book method with the 24mm spanner on the hub tool and a standard chain whip.
Also reveresed the chainwheel and fitted my first new chain.
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 26, 2009, 08:50:50 PM
Nice one Dave, good to hear of someone with a success story!  I had mine reversed by SJS while I was having some new rims put on.  I might try and do it myself next time.  When you've reversed it will it come off clockwise or anticlockwise next time?  I can't visual the threads.
Title: Re: sprocket reversing problem anyone?
Post by: davefife on January 27, 2009, 03:06:50 PM
you should do it yourself, its not difficult!  Your thread question is a misnomer as the sprocket is threaded the same way from both sides - a standard clockwise - its not threaded clockwise from one side only.  The best way to find your way in mechanicals and basic engineering principles is to have a go, a good set of quality tools are essential, then any manual (on line or paper from the library) to familiarise yourself, then go ahead and get a feel for it on your own bike.
Zen and the art of motorcycle mainatainance is a good read to understand how parts move and wear and give you an understanding of how to feel the machine adjusting and changing.  Context is everything!

For those trying to estimate chain life, mine was 9,000 miles, i reversed it at 4,000 and took out a link at 5,500. 
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 27, 2009, 03:50:12 PM
Thanks for clarifying the threading.  I probably would have had a go at the sprocket myself except that I needed a new rim anyway and wasn't confident I could make a good job of the rohloff on what would have been my first wheel build.  Also, the stories on here suggested my tools were not up to the job -I'd have needed the rohloff tool and possibly a stronger chain whip.

My sprocket was showing some wear (wave profiles) after about 6000 miles.  It could probably have done another 3000 but I decided to have it reversed anyway while it was at SJS.  I swapped the original chain for a stainless version after 1500 miles, then broke this repalcement recently after it had done another 5000 miles, and I am now back onto the original.  I shall replace it with a new one next time I'm tinkering with the bike and keep the original as a backup.
Title: Re: sprocket reversing problem anyone?
Post by: pdamm on August 01, 2009, 07:24:35 AM
I have just replaced the rear sprocket, front chain ring and chain on my Raven Tour.  It turned out to be an easy job.  The chain had just over 16,500 km on it and had elongated to almost a ľ inch over 12 links.  The teeth on the rear sprocket were worn down to about 3/5 of the width of the teeth on the replacement.  I had no problems getting the sprocket off with a chain whip and spanner just like the manual says.  One interesting thing was the chain had started sticking a little.  It wouldnít flop loosely at each link, some of them stuck a little even with lots of lube applied.  With the chain tension now quite slack it gave the chain line a zigzag look in a few places. 

Peter
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 31, 2010, 01:04:51 PM
Finally, changed my sprocket after 10,000 miles.  It was reversed after 6000.  It had worn to fairly sharp points and I think was leading to my having problems with broken chains.  Tried the 'rowing' method but couldn't move the sprocket.  Then broke my chain whip (cheap halfords), then got a friend around with a better one and between us we managed to shift it.  All running smoothly again, although I might replace the front chainring before the chain wears again.  Like all these more technical jobs on the bike they are not nearly as bad as anticipated.
Title: Re: sprocket reversing problem anyone?
Post by: Cake on February 01, 2010, 04:23:42 PM
Thats good to hear Geo - i'm going to reverse mine for the first time when the chain needs tensioning next (1500 miles or so and the chain will be replaced and chainring reversed).

I'm not expecting it to be terribly willing to part from its current position due it having been there for 11000 miles....
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on February 02, 2010, 09:57:00 AM
Thats good to hear Geo - i'm going to reverse mine for the first time when the chain needs tensioning next (1500 miles or so and the chain will be replaced and chainring reversed).

I'm not expecting it to be terribly willing to part from its current position due it having been there for 11000 miles....

Wow, that's a lot of miles on one small sprocket!  It is amazing how different they wear.  There would literarly have been nothing left of mine had I waited that long to reverse.  I'd have a new sprocket in reserve in case the new chain doesn't mesh with the reversed sprocket.  Good luck!
Title: Re: sprocket reversing problem anyone?
Post by: Cake on February 02, 2010, 11:05:39 AM
I think i'll need a bit of luck!

I only use the RT on tarmac and clean the chain pretty regularly so perhaps that is a factor.

Being a prepared sort, i have a spare chain, chainring and sprocket just in case.... Well, it wouldn't be right having to wait for parts and not being able to ride it!

Title: Re: sprocket reversing problem anyone?
Post by: stutho on February 02, 2010, 11:27:38 AM
Wow, that's a lot of miles on one small sprocket! 
I too got 12,000 miles out of one side of the sprocket - and one chain.  I think PH may have got even more!
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on February 02, 2010, 12:59:37 PM
I think i'll need a bit of luck!

I only use the RT on tarmac and clean the chain pretty regularly so perhaps that is a factor.

Being a prepared sort, i have a spare chain, chainring and sprocket just in case.... Well, it wouldn't be right having to wait for parts and not being able to ride it!



Yes, I ride a fair bit offroad and probably don't clean the chain often enough.  In those 10,000 miles I have broken three chains!  The first was a PC68 which suffered a bizarre breakage of 3 internal links reported elsewhere http://www.thorncycles.co.uk/forums/index.php?topic=1934.0.  I think it got munched by the chain ring when running it a bit slack.  Then I tried a half link chain which never really seated well on the worn sprocket and attracted grit like there was no tomorrow.  It fell apart, was repaired twice and then finally the out links broke.  The original PC48 went back on for the winter and broke two weeks ago -again a fracture in an external plate.  I'm hoping the new sprocket will help and I'll order a new chain ring although this looks OK.
Title: Re: sprocket reversing problem anyone?
Post by: Cake on April 18, 2010, 10:37:57 AM
Yesterday afternoon was spent rejuvenating the transmission on my RT.

After 12000 road miles the chain was very slack and the teeth on the rear sprocket were taking on a very wave-like appearance, although the wear on the chainring was hardly noticeable at all.  Also, despite the miles, the E.B.B. was just over halfway through its allowable adjustment - so the £4.99 KMC Z51 is not prone to too much "stretching" for my type of use.

I secured the chain whip to the sprocket with a few cable-ties and was quite surprised when it (the sprocket) loosened off - i was expecting much more resistance after reading about the many trials others had been through. I used a bit of very fine and used wet and dry (wet) and lightly pushed the face of the sprocket around on it under its own weight.  This soon got rid of the staining / crud on the surface that would be in contact with the oil seal.  A bit of copper grease on the thread and a smearing of hub oil on the oilseal face and the sprocket was reversed.

After reversing the chainring i refitted the back wheel and fitted a new Z51, using the original indents in the E.B.B. (hopefully this will also have reduced the stress / wear on the rather loose fitting thread / set screw arrangement).

A flush and an oil change later (i drained the oil before removing the sprocket to avoid a slick) and i now have one super smooth riding RT - sweet.

Overall i found this very straight forward - not nearly as problematic as i was expecting and hopefully the sprocket will last another 8000 miles or so.  Brilliant.

As an aside, i was tempted to replace the Marathon Plus while the wheel was off, but despite 12000 miles it still has a couple of thousand miles left in it i think.  I'll use it until i get a (first!) puncture and then bin it.

Title: Re: sprocket reversing problem anyone?
Post by: Crudson on April 18, 2010, 08:11:21 PM
Quote
As an aside, i was tempted to replace the Marathon Plus while the wheel was off, but despite 12000 miles it still has a couple of thousand miles left in it i think.  I'll use it until i get a (first!) puncture and then bin it.

What do they surface the roads with round your way - marshmallows? Thats incredible!!!
Title: Re: sprocket reversing problem anyone?
Post by: Cake on April 19, 2010, 07:04:44 AM
Some marshmallow surface - the rest is potholes and hedge trimmings, so i think it is the tyres!  I did used to get plenty of punctures when i used "normal" road bike tyres on other bikes.

I'm sure having made the claim about no punctures etc. etc. and mentioning the word puncture so often, the puncture fairy will now deem it necessary to strike me down with my two and a bit years worth!
Title: Re: sprocket reversing problem anyone?
Post by: Cake on May 09, 2010, 09:18:04 AM
I bloody knew it!  400 miles after my no puncture brag, i got a slow puncture from a large spearhead shaped piece of glass.

The tyre still has a few miles in it and after finding out about the Marathon Plus in 1.5" guise i'm going to hold out until they are in stock somewhere.

The new transmission is a dream - no oil weeping problems, just smooth riding.   ;D
Title: Re: sprocket reversing problem anyone?
Post by: Crudson on May 14, 2010, 08:36:01 PM
Quote
I bloody knew it!  400 miles after my no puncture brag, i got a slow puncture from a large spearhead shaped piece of glass

Law of the Sod - Your blessed run comes an end; hard lines Cake.
If it's any consolation, I punctured on way to work this week [glass aswell] in my month old Continental City Contacts
[y'know, the ones which come with a 1 year puncture guarantee; harrumph]
Title: Re: sprocket reversing problem anyone?
Post by: gearoidmuar on June 23, 2010, 12:03:50 PM
Now: Sometimes experience is what you DON'T need :-[
I didn't need to reverse my sprocket yet but decided to try it as I'm doing a big tour in two weeks and I may need to do it on that. I've often taken blocks off wheels before, as a testament to which I have about 6 block removers.

So I start with the Rohloff one. I cannot shift it. Try really hard. No. Put a lever on chainwhip. Not a budge.
Thinks....
I'm going in the wrong direction.. Search through the Rohloff book (it's BADLY indexed) and eventually find the diagram. I have been going in the wrong direction. All other blocks come off the other way.
It's going to be really difficult now??
Naw, first effort, off no problem.  ;D
Title: Re: sprocket reversing problem anyone?
Post by: farnorth on August 09, 2010, 09:07:18 PM
Interesting to read this thread.  My 15 tooth rear sprocket looks distinctly worn (asymmetric teeth), but has probably done less than 4000 miles in 1.5 touring seasons. This doesn't really gel with comments that suggest that they last for a long time.  I'm on my second chain. I don't apply excessive force to anything, since I'm only 65 kg!  I also note that only a 14 tooth sprocket seems to be available for purchase from SJS.
Title: Re: sprocket reversing problem anyone?
Post by: rualexander on August 09, 2010, 10:39:42 PM
Interesting to read this thread.  My 15 tooth rear sprocket looks distinctly worn (asymmetric teeth), but has probably done less than 4000 miles in 1.5 touring seasons. This doesn't really gel with comments that suggest that they last for a long time.  I'm on my second chain. I don't apply excessive force to anything, since I'm only 65 kg!  I also note that only a 14 tooth sprocket seems to be available for purchase from SJS.


All sprocket sizes are showing here : http://www.sjscycles.co.uk/product-Rohloff-Rohloff-Speedhub-500-14-Hub-Gear-Reversible-Sprocket-Steel-10342.htm
Or you can get them cheaper here : http://activesport.co.uk/shop/category_851/Rohloff-Spares.html?shop_param=cid%3D%26
Title: Re: sprocket reversing problem anyone?
Post by: wowbagger on January 17, 2013, 03:02:15 AM
I took my sprocket off today.

My technique is to line the chain whip and the wrench up so that I can hold them in both hands, then squeeze. Dead easy! It came off in a matter of seconds and I didn't even swear. It's over 4500 miles since I last removed it, and I'm 113kg. The chain was desperate for bein replaced: I suspect that last year's dreadful wet weather took its toll and I was using a different chain lube. I find Purple Extreme to be very good, but for a change I was using something called "Finesse Multi Lube Plus" which is a much sticker lube and makes the chain filthy after a while.
Title: Re: sprocket reversing problem anyone?
Post by: Gary (a.k.a. cake) on February 19, 2013, 09:40:07 PM
I had to replace the rear sprocket on my RT today after discovering two broken teeth. 

I'm not complaining though, it's allowed me to propel myself over 20700 miles. I reversed it after 12000 miles. 

Despite having done another 8700 miles it came off without any problems at all.  Big Park Tools chain whip, a few cable ties and a big spanner - lovely!

I put a new chainring on and also a new chain and the bike now rides like a dream.

So my second experience of sprocket removal / reversal was again a positive one!
Title: Re: sprocket reversing problem anyone?
Post by: StuntPilot on February 20, 2013, 12:10:42 PM
I have found a useful video from Shane Cycles on removing a Rohloff sprocket. The 2x4 method is used accompanied by some relaxing music to help
with the pressure and stress of the process!

http://www.youtube.com/watch?v=BLnR_QgpvhY (http://www.youtube.com/watch?v=BLnR_QgpvhY)
Title: Re: sprocket reversing problem anyone?
Post by: mattwhitford on September 17, 2013, 03:36:21 PM
Help!
I bought a new chainring, Rohloff chain and Rohloff sprocket, but really struggled to get the old Rohloff sprocket off.  Ended up nailing the old chain (which I removed with a chain splitter) to a length of 2x4inch wood and used that as the chainwhip (worked a treat).  Spanner with a pipe on the removal tool, length of 2-b-4 chainwhip.  The sprocket suddenly cracked with application of tremendous force.  So much so I lunged forward and cracked my head on the crossbar and had a lump and bruise for a while (totally my own fault - I was obsessed with getting the bstrd thing off so much so I didnt role play what would happen if it did suddenly give)

Problem is:
Since putting it all lovingly back together, it looks amazing, but there's a lot of drag on the freewheel.  I am sure I might have damaged the Rohloff somehow as the ratchet when freewheeling makes a buzzing sound off and on- like an amplified mosquito noise.  And the freewheel feels stiff.  Imagine the chain is ridiculously tight (which it is not) - that's what it feels like.

It's really annoying



 
Title: Re: sprocket reversing problem anyone?
Post by: Dave Whittle Thorn Workshop on September 17, 2013, 04:16:22 PM
Try this:

(http://i44.tinypic.com/2mfuch.png)
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on September 17, 2013, 04:19:55 PM
Congratulations on getting the sprocket off.  It's not something to do when you have the vicar for tea!

On the noise, hopefully you shouldn't have damaged anything fundamentally.    As a first thought slacken the skewer a bit, then the chain tension, then as Dave suggests whack it with a mallet?
Title: Re: sprocket reversing problem anyone?
Post by: mattwhitford on September 17, 2013, 04:48:22 PM
That's great - thanks guys! Just followed the advice - whacked both sides with a mallet.  It IS much better.  But I cant remember now, if the sprocket should have some resistance or not.  It's not tense any longer but still a little resistance.

Title: Re: sprocket reversing problem anyone?
Post by: Dave Whittle Thorn Workshop on September 18, 2013, 12:10:45 PM
Some resistance is normal, this is due to the seal rubbing on the tubular section of the sprocket to form a seal.

Hope this helps.
Title: Re: sprocket reversing problem anyone?
Post by: revelo on July 29, 2015, 02:18:07 AM
I've discussed this before, but since this is a permanent post, I'll mention it again here. Pedro's Vice Whip makes for easier Rohloff sprocket removal. My technique is to sit on the floor barefoot, with my toes holding the bottom of the rim and the top pressed against my chest, then put the vice whip and wrench in place and jerk back towards myself in a rowing motion.
Title: Re: sprocket reversing problem anyone?
Post by: lestat_12345 on May 23, 2018, 08:33:46 PM
Hi All,

I already have a Rohloff but bought another albeit secondhand. I am trying to remove the sprocket on the secondhand unit but it won't budge. I'm using the method outlined within this post which I have alway used before this post (the youtube video was the one I watched when I first wanted to remove a Rohloff sprocket). The unit is an old one (around 10 years) and I don't think the sprocket has been removed since new. It has also been stored unused for a number of years. What can I do to get the sprocket off? I am using a long chain whip and wrench so there should be enough leverage. I'm also relatively strong so I can normally apply enough force to get the sprocket off without issue.

Thanks,

Richard.
Title: Re: sprocket reversing problem anyone?
Post by: TouringMechanic on October 19, 2018, 05:34:40 AM
I got my rear sprocket off a few days ago and can tell you, it would have never be possible witouth a vice. It is as tight as a screwing part on a bicycle goes. I put an abundance of grease on it before putting it back on. If you consider taking an old sprocket, probably with a bit of rust inside, make sure you have a quality vice and as long of a lever for the chain whip, as you would need it for a frozen bottom bracket.
Title: Re: sprocket reversing problem anyone?
Post by: mickeg on October 19, 2018, 05:11:54 PM
I apparently had better luck than you, the tools I used are in the photo.  They are unusually large, but I did not need a cheater bar or a big vice.  Sprocket had been on for about three years, I just pulled it off to see if the grease on the threads needed renewing.  Came off quite easily, and yes I put some grease on the threads before putting it back on.

I suspect with the new splined carrier, a lot more Rohloffs will have a stuck part in the future when nobody bothers to remove the carrier until it becomes absolutely necessary.

Another thread for reference here:
http://thorncyclesforum.co.uk/index.php?topic=12931.0

Title: Re: sprocket reversing problem anyone?
Post by: evanprice on January 07, 2019, 01:44:35 PM
Hi All

I am in the Congo and just replaced my sprocket after about 30k km on the road...needless to say it was extremely tight and there was to be no reversing, Iím stunned that it still worked in this state!

I have the correct removal tool but as it was so tight and I am not well versed in the process I mistakenly applied load to the wrench/spanner while also applying load to the chain whip, and now the sprocket freewheel movement is very stiff and the gears donít change or engage properly...so clearly Iíve buggered something up!

Any ideas on how I go about fixing this issue would be much appreciated as Iím not sure how to undo the tightening action, thanks.

Evan
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 07, 2019, 04:38:49 PM
Wow, that's a lot of wear!  I think you need to try the rohloff recommended rubber mallet procedure:

 'hit the axle peg firmly with a rubber mallet. Once from the sprocket side (right) and once from the axle plate side (left). This will loosen-up the tension on the bearings.'

This is from the rohloff handbook https://www.rohloff.de/fileadmin/user_upload/3_Service_En_2015_03_web.pdf
Title: Re: sprocket reversing problem anyone?
Post by: mickeg on January 07, 2019, 05:14:34 PM
Or lacking a rubber mallet, maybe using a rubber soled shoe as a mallet.
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 07, 2019, 05:37:16 PM
Or lacking a rubber mallet, maybe using a rubber soled shoe as a mallet.

Yes indeed, In fact I'm surprised there isn't an officially approved mallet on the rohloff website!
Title: Re: sprocket reversing problem anyone?
Post by: evanprice on January 10, 2019, 02:44:54 PM
Thanks for the insights - that procedure did the trick and the gears  seem to be working as before...various heavy implements substituted for a rubber mallet!
Title: Re: sprocket reversing problem anyone?
Post by: geocycle on January 10, 2019, 04:02:19 PM
Thanks for the insights - that procedure did the trick and the gears  seem to be working as before...various heavy implements substituted for a rubber mallet!
Fantastic, so pleased it worked and thanks for getting back.
Title: Re: sprocket reversing problem anyone?
Post by: lewis noble on January 10, 2019, 06:30:36 PM
Good luck and safe travels for your onward journeys . . . . Where to now??

Lewis