Crack noise after shifting

[hendrich]

Lately from our Rohloff, I hear a crack noise after shifting on most if not all gears. I suspect this is the main drive pawls properly seating when significant force is applied to the pedals. I not sure if pawls is the correct term for the power engagement point on the axle of a Rohloff (if possible, please point to the correct object on the Rohloff exploded diagram). This suggests that the engagement shaft (where the pawls dig in) has developed some abnormality.

I have changed the oil yearly, sometimes twice, and oil leakage is not a problem. The hub has 40,000 km and is on a tandem. Is this a problem that others have experienced?

Thanks, Mike

[Danneaux]

This may be no help at all but is at least free to try: Check rear q/r skewer tension.

Where the cracking is associate with force, it may be the axle working in the dropouts or associated. Similarly, I'd check the machine screws are properly tight on the torque reaction arm.

On the drive side, are you using a slotted/circlip-retained drive sprocket? Those can become a bit worn/loose on the carrier and make a noise on/after shifting.

EDIT: 'Came across this checklist for Rohloff-associated noises in my link files...
https://cyclemonkeylab.blogspot.com/2019/04/tech-talk-rohloff-speedhub-50014-making.html

Best, Dan.

[hendrich]

Thank you for the advice, in response to your suggestions.....

-Check rear q/r skewer tension .....it is tight

-check the machine screws are properly tight on the torque reaction arm.... the bike was built for Rohloff, the torque arm seats in a slot in the dropout plate (no screws)

-Check the slotted/circlip-retained drive sprocket... wheel off bike, the sprocket has no noticeable angular or side-to-side play

It occurs to me that the problem cannot be the seating of pawls to the freewheel axis (unclear proper terminology for Rohloff). The crack sound occurs only once after a shift and with initial pedaling. It does not occur after coasting and then pedaling without changing gears.

[mickeg]

One of the planetary gears is only used for gears 1 through 7.  Not for gears 8 through 14.

Does it occur after any shift?  Or does it only occur immediately after shifts from gears 1-7 up to gears 8-14, or back from 8-14 down to gears 1-7?

Gear 11 is direct drive.  Gears 12-14 are overdrive.  Does it only occur when shifting from below gear 11 to above gear 11, or from above gear 11 to below gear 11?

[hendrich]

Thank you for possible checks. I was wrong previously, it only occurs in the 8-14 range. I will do some more testing, switching from low to high, and focusing on which gears it happens.

[mickeg]

If it only occurs in 8 to 14, that likely rules out a problem specific to the low range planetary gears.  That said, I would expect it to occur in gears 1 to 7 too.  I was specifically thinking that if it only occurred in gears 1-7, that would imply that it was specific to the low range planetary system, but your symptoms confuse me a bit.

If it only occurred once when you shifted from below 11 to above 11, or once back from above to below, that could be from the hub torque limiting components.  For example if your skewer was loose which you already confirmed was not the case.