I mounted new-old wheels with a 6spd Shimano freewheel recently bought on Ebay on my wife's Bianchi and now the chain is skipping badly on the 2nd smallest cog, which has teeth that are more "twisted" than the larger cogs. The freewheel looks to be in like-new condition. The bike is a hodgepodge of parts with Ultegra 8spd barcons ratcheting in friction mode, 8spd chain, and Veloce 10spd CT crank.

I'm wondering if some combination of the chain being too narrow, the cog's teeth being effectively too wide, and the ratcheting being too coarse prevents it from running smoothly.

Thanks for any ideas.

i had the same issue with my bridgestone. new 6spd suntour freewheel, friction shifting. it was very annoying. it was the chain, i had a newer 8spd chain and it was touch narrow. swapped it out with an older chain ( 6spd) issue resolved.

good luck, hope it helps

Is the chain skipping, or the freewheel skipping?

Could be either the chain or the freewheel. If you have a chain wear gauge, check the chain. See if there is a sticky link.

Look to see if one tooth on the freewheel is bent, lube the freewheel.

I would try another chain to see if that's the problem. If it still skips, most likey the freewheel.

Can you duplicate on a stand, or only under load?

Thanks people.

The 8spd chain is pretty new with no kinks. I have a 6spd chain to try and will find out if it will work with the 10spd CT crank.