Disturbing noise...

[Cake]

I was out for a ride last week and stopped for a moment to munch down a flapjack.  When i started riding again there was immediately a horrible crunching, two gears trying to engage at once type of noise which was also was very clearly felt through the pedals.  I changed gear a couple of times to make sure it was not a dodgy gear change on my behalf but it continued.

So i stopped and had a good look over the chain and sprockets just to make sure all was well and that it was coming from the hub, but that was all in order as i had cleaned the chain the previous day after  it got a good soaking in heavy rain.  So i had no choice but to head home very slowly.  The "crunching" for want of a better description occurred in every gear and wasn't a regular consistent thing.

Anyway, after a quarter of a mile or so it improved bit by bit and after a mile or so had completely disappeared.  To make sure of this i rode a further 15 miles with no problems at all.  Once home i gave it a thorough flushing and an oil change.  I filtered the drained oil and found a couple of minute (really minute!) particles of swarf (as i did after the first oil change, which seemed to stop a very infrequent slip).  After the oil change the hub is yet again a bit smoother and feels absolutely perfect (including some hard out of the saddle climbing type testing!). 

I decided to talk to SJS to see what their opinion was and it seems as though it probably was a piece of swarf causing gear selection to be affected briefly.  They suggested a flush and oil change, which i had already done.  They did of course say that if there was any future problem with the hub at all it would be dealt with immediately - top service and reassuring.

However, it seems likely that the problem was a tiny piece of material as i also suspected - it would account for the immediate start of the problem, then the gradual improvement as it worked through and eventually ended up in my waste oil container.  All part of the running in process i suppose!

Has anybody else had any similar experiences?

[Tony]

I am currently having a similar experience.  I took it in to All Saints Road shop in Notting Hill and they said everything looked fine.  I am now waiting on some oil from SJS to do a change.  I hope it fixes it.  I have about 12K km on it and it has been great except for the last week or so.

[jags]

just curious here but how would anything get into a sealed hub,or was it something that came loose inside ,also when you did flush out the hub did you discover anything that should not have been in there in the first place emm. ahh give me a good derailer any day.

[geocycle]

Hope you both get this fixed.  According to the manual one of the roles of the oil change is to get rid of small bits of crud left over from the manufacturing process.  I hope this is what you're dealing with here.  Does sound a bit dramqatic though... Not being able to see in the hub is a bit disempowering but if all goes quiet again I hope your trust is quickly restored. 

[Cake]

Hi Jags, its swarf - very small particles which come from the running in and general wearing process.  When metal wears against metal, for example, the missing metal must go somewhere - larger (relatively speaking) particles are the swarf.

Do you remember the magnetic sump plugs on Minis and Metros?  When the oil was changed the plug had loads of tiny metal fragments on it (the plugs were magnetic to draw the fragments out of the oil) - these pieces came from the wearing process.

When i changed the oil the first time i kept everything as clean as possible to avoid bits and pieces of grit etc. falling off the wheel/mudguard into the drain hole.  Nothing came out with the oil that wasn't originally in the hub as far as i could tell!

I've just read Geocycles post and bits from the manufacturing process seems the most likely answer. 
Hopefully all will continue to be well and a few hundred miles down the road will see my trust restored!

[jags]

good stuff cake i hope all is ok and you dont have any more problems,

[Cake]

Thanks Jags - i hope so too!  I've just enjoyed a 25 mile ride (in the dry this time) and it was as smooth as silk, as ususal (for 99.99999% of the time!).

Tony, let us know if the oil change cures it.  I was told that the flush is the most important part of the oil change.  I rode mine for about 4 miles or so in 3rd and 5th for a large part of the time - i'm sure you do the same seeing as you've covered many more miles than myself!

I'm also pleased that i bought the oil and cleaning oil in bulk - perfect for that unexpected need! The wallet moaned at the time but it has got over it now and put it in the past....

[brummie]

Quote: I was out for a ride last week and stopped for a moment to munch down a flapjack.  When i started riding again there was immediately a horrible crunching, two gears trying to engage at once type of noise which was also was very clearly felt through the pedals. 

- I bet you'd dropped a chunk of 'well cooked' flapjack in your chainwheel  - I'd recommend malt loaf in future - it just falls off a well lubed chain !

[Cake]

Brummie, it couldn't possibly have been burnt or over baked flapjack, twas made by the hand of my mother-in-law and is therefore perfectly baked every time!

I'm sure you can understand my position!  I may switch to malt loaf, i don't think she can make that....

[brummie]

I'm glad you seen the funny side...on a serious note tho' I've been riding my Rohloff for a fair few thousand miles & am totally convinced it'll  probably never fail despite the ( very ) occassional crunched gear change it performs flawlessly & has gotten smoother /quieter over time.

[Cake]

I've ridden over 1000 miles since this noise occurred and disappeared and the hub hasn't missed a single beat, its just got a little bit smoother - confidence is fully restored!

Gary.

[geocycle]

Glad to hear you've got it sorted.  It's always good to know when a problem has been solved.