New jockey wheel > skipping chain

hi, how far do you run down jockey-wheels¿ (mine are down to sharky teeth).

so i ordered one replacement-wheel (one first to see if it fits) and put it in.

now the chain starts skipping, strangely enough -and even more so in most, but not all gears.

any ideas? gracias!



ps, ordered a second wheel - maybe changing both at the same time will stop the skipping?