Is it the chain skating over the Rohloff's sprocket or on the chainring itself?
yes. in 3 letters. the sprocket shows no wear whatsoever and has done less than 2-3,000km and has been reversed in that time (bearings were greased). I expected to get at least 14,000km from it if not more!
How badly is the chain jumping ??
too badly to use. top of every pedal stroke in each side to the point where I can not keep my foot in the toe strap (remember I can't use spd's).
On a single chain ring we can get it setup so that it does not skip at all.. that is the middle chain ring, so under tension it is fine. Once it drops to the inner chain ring chaos reigns. and it is consistent through the entire chain length so none of the chains give any difference. Same chain manufacture and model as it was running on my expedition bike (where the wheel came from)
I'll look at the B screw tomorrow morning. It can't make matters worse. Worst case scenario I only have the middle chainring available until my OH can fit either the 2nd hand Rohloff chain tensioner which looks desperately short - but perhaps that is just the photos, or the long reach derailleur which hopefully have a strong spring. I did mention it to Kevin the need for one with a strong spring and he agreed.
) I can see it already has tube chain guides to stop the chain 'bouncing' so I think just fitting a long cage rear mech should sort it and enable all 3 front rings to be used. I would suggest trying to 'lock out' the adjustment though using the limit screws to stop the mech from moving sideways and spitting the chain off, possibly a longer screw on 1 of the stops once it is aligned with the sprocket or use a very short length of cable with the nipple in the adjuster and the bare end in the clamp so that you can turn the adjuster to lock it into place.
