Rumbling Rohloff

[ukdodger]

Two days into my last tour my Rohloff started making rumbling noises in gears 1 - 6. The lower the gear and harder the pedaling the louder the rumbles. All Rohloffs make a rasping noise in gears 1 - 7 which is normal but I havnt heard this noise before. So do any other Rohloff owners have the same problem or is a bigger problem in the post?

[Brucey]

so, normal service in gear 7, but not 1-6?

And what of gears 8-14?

Daft question, but it definitely isn't the chain? This can see higher tensions when the lower gears are used for climbing etc and make more noise.

Did you carry out any adjustments by any chance? One of the things that might make a sudden change is if a previously slack chain was adjusted tight; this can cause rough running under load.

cheers

[rualexander]

My guess would be chain, sprocket or chainring related, or if you have a long torque arm, possibly some movement there?
Or if you have chain tensioner, it could be from that?
What bike is it on?
I've experienced various creaking/grumbling noises in lower gears of my Rohloff over the years but none of them have been due to any internal problems.

[geocycle]

Not come across anything resembling a rumbling from the Rohloff. A friends developed a creaking under load which was due to him having the rear skewer too tight. I'm with Rual in his suggestion about the chain. It may be warn, incompatible with the sprocket or just too tight?

[ukdodger]

Thanks for the replies. If it's the chain, chainring or sprocket how is it making that noise. How is the best way to find out if it is one or more of those. There's no chain tensioner on my setup. I dont use this bike in between tours but after each tour I give it a good service including taking the wheels off then reassemble it ready for another tour. So yes some adjustment would have been made to the chain tension but I'm careful not to have it too tight or too slack. Gears 7 - 14 make no noise.

[geocycle]

I guess it's trial and error. I'd start with the easy bits, slacken off your skewer slightly and ride up a hill. If no luck then it is likely to be some part of the drive chain. Check the chain carefully for any obvious flaws, clean and refit. If problem persists Check the sprocket for asymmetry on the teeth and reverse the sprocket. If you've not done that before then it can be a pain and involves a lot of profanity. Try a new chain with the reversed sprocket. If this doesn't work then reverse the chain ring. If still no joy then an oil change can sometimes help. Finally, contact SJS or other rohloff dealer.

[ukdodger]

I guess it's trial and error. I'd start with the easy bits, slacken off your skewer slightly and ride up a hill. If no luck then it is likely to be some part of the drive chain. Check the chain carefully for any obvious flaws, clean and refit. If problem persists Check the sprocket for asymmetry on the teeth and reverse the sprocket. If you've not done that before then it can be a pain and involves a lot of profanity. Try a new chain with the reversed sprocket. If this doesn't work then reverse the chain ring. If still no joy then an oil change can sometimes help. Finally, contact SJS or other rohloff dealer.

Thanks.

[Brucey]

If it's the chain, chainring or sprocket how is it making that noise. How is the best way to find out if it is one or more of those. There's no chain tensioner on my setup. So yes some adjustment would have been made to the chain tension but I'm careful not to have it too tight or too slack. Gears 7 - 14 make no noise.

gears 1-6 don't use any unique parts/gear stages inside the hub that are not also used in other gears, so this is strongly suggestive that the fault perhaps isn't inside the hub, but is outside it. Even if there was a suspicion that there might be an internal fault, it would still be wise to eliminate the external things first.

As Geocycle suggests, substitution is a surefire way of determining that the chain/sprocket/chainring is/isn't the problem. Worst case here is that you end up with some spare parts that you didn't really need yet, and you waste time doing it.

As for "how?"; as per my earlier post, if you remove all the slack from a worn chain (i.e. take the slack to a point that might be fine with a new chain/sprocket) the transmission will definitely become noisier than normal. The reason this happens is that a worn chain has a pitch that is longer than normal, and it wants to sit further out on the chainring/sprocket teeth, i.e. where the distance between the teeth matches the slightly elongated chain. If you take too much slack out of it, it can't sit further out where it needs to, and it will run rough. It will also be wearing everything at an accelerated rate, too.

If your noise 'appeared' suddenly (or at least not long) after a chain adjustment, it is very likely that this is the cause.

A simple test for this problem is to adjust the chain so that it is slacker (maybe 2" of vertical free play) and go for a ride. You may find that suddenly, your transmission is working smoothly again!

The other thing that can happen is that (with chainrings and sprockets that have an even number of teeth) every other link in the chain wears unevenly and so do the teeth; if the chain is put back on 1T away from where it was, rough running can ensue. Sheldon Brown has a page that describes this. However IME the chain needs to be very worn before this is a big issue, but maybe certain chains (that I don't use) are more prone to this sort of thing.

cheers

[ukdodger]

If it's the chain, chainring or sprocket how is it making that noise. How is the best way to find out if it is one or more of those. There's no chain tensioner on my setup. So yes some adjustment would have been made to the chain tension but I'm careful not to have it too tight or too slack. Gears 7 - 14 make no noise.

gears 1-6 don't use any unique parts/gear stages inside the hub that are not also used in other gears, so this is strongly suggestive that the fault perhaps isn't inside the hub, but is outside it. Even if there was a suspicion that there might be an internal fault, it would still be wise to eliminate the external things first.

As Geocycle suggests, substitution is a surefire way of determining that the chain/sprocket/chainring is/isn't the problem. Worst case here is that you end up with some spare parts that you didn't really need yet, and you waste time doing it.

As for "how?"; as per my earlier post, if you remove all the slack from a worn chain (i.e. take the slack to a point that might be fine with a new chain/sprocket) the transmission will definitely become noisier than normal. The reason this happens is that a worn chain has a pitch that is longer than normal, and it wants to sit further out on the chainring/sprocket teeth, i.e. where the distance between the teeth matches the slightly elongated chain. If you take too much slack out of it, it can't sit further out where it needs to, and it will run rough. It will also be wearing everything at an accelerated rate, too.

If your noise 'appeared' suddenly (or at least not long) after a chain adjustment, it is very likely that this is the cause.

A simple test for this problem is to adjust the chain so that it is slacker (maybe 2" of vertical free play) and go for a ride. You may find that suddenly, your transmission is working smoothly again!

The other thing that can happen is that (with chainrings and sprockets that have an even number of teeth) every other link in the chain wears unevenly and so do the teeth; if the chain is put back on 1T away from where it was, rough running can ensue. Sheldon Brown has a page that describes this. However IME the chain needs to be very worn before this is a big issue, but maybe certain chains (that I don't use) are more prone to this sort of thing.

cheers

Thanks Brucey I'll give it a try and post the result. I hope the problem isnt the hub!

[Tiberius]

I guess my recent experience backs up what 'geocycle' posted.....

I recently fitted a new chain to my Rohloff bike....What a racket !!.....crack/crack/creak/groan/crack.

Flipped the rear sprocket....SILENCE.

I've fitted a new chain before with no issues. I didn't think that the sprocket or chainring looked too bad but I guess that they must have been bad enough to effect the way that the new chain sat/ran.

In case it matters. Standard Rohloff 16T sprocket/KMC X1 chain/Middleburn 36T chainring...The sprocket and chainring had done approximately 7,000 hard miles...sand/salt water/dirt/mud/winter etc.....

The fact that the OP didn't fit a new chain points to what 'Brucey' was saying about the even toothed sprocket/chainriring combination and refitting the old chain 'in sync' I did read up on this myself but as I was fitting a new chain it didn't really matter.

[Brucey]

yes if you fit a new chain to a worn sprocket/chainring it will be noisy. The reason is that the 'hook' on the tooth form will snag the chain, as it engages at the sprocket and as it disengages from the chainring. Normally the sprocket wears faster than the chainring so the noise will often come from the sprocket alone. Adjusting a worn chain too tight causes a similar noise but the underlying reason is slightly different.

BTW if you are a skinflint and you hear that noise after fitting a new chain, you may be heartened to hear that it will eventually go away if you ride far enough. But you might have to ride a very long way.... if you can't be bothered to remove the sprocket (a very real consideration with the original Rohloff design...) then you may get some relief by 'de-hooking' the sprocket using a dremel tool or similar. A new/turned sprocket is best of course, but de-hooking may work well enough.

cheers

[Tiberius]

BTW if you are a skinflint and you hear that noise after fitting a new chain, you may be heartened to hear that it will eventually go away if you ride far enough. But you might have to ride a very long way.... if you can't be bothered to remove the sprocket (a very real consideration with the original Rohloff design...)

Yes, I did notice that the noise was dropping off the more that I rode the bike but I knew that it wasn't 'right'. I was keen to get it 'right' and curious to find out exactly what was wrong.

I have the Rohloff sprocket tool and a decent chain whip (crucial) so flipping the sprocket was stright forward.

I guess that I am a skinflint.....a skinflint who should replace his sprockets more ofter...

[ukdodger]

Just an aside form the original post. I took the sprocket off and also changed the oil. Without knowing I laid the wheel sprocket side down (without the sprocket replaced) and all the oil drained out much to my extreme anger I replaced the sprocket and the oil stopped leaking. So it looks as if the sprocket itself is also the oil seal. That doesnt sound like good design to me. What do others think?

[Brucey]

I'm struggling to think of an IGH where the sprocket mounting doesn't also include part of the sealing/dust shield retention. If it is a bad design it seems a very common one.

Also, don't Rohloff recommend that you don't lay the hub down on its side anyway?

BTW did the changes sort out the transmission noise you had?

cheers

[Gattonero]

Just an aside form the original post. I took the sprocket off and also changed the oil. Without knowing I laid the wheel sprocket side down (without the sprocket replaced) and all the oil drained out much to my extreme anger I replaced the sprocket and the oil stopped leaking. So it looks as if the sprocket itself is also the oil seal. That doesnt sound like good design to me. What do others think?

To flush the hub is not a bad thing at all. It is normal for that hub to leak a bit of oil anyway, the good news is that nothing really goes in