Why is my chain riding up and skipping teeth on the freewheel? Due to a number of reasons, I would like to keep my freewheel at all costs (It's a Sachs freewheel, the bike has all sorts of more 'vintage' components, and they're hard to come by). From reading all the related questions, it seemed the solution would be a new chain, and the teeth certainly don't look worn enough (to me at least) to warrant the freewheel needing replacement.

However, with both a brand new 7/8 speed chain, and the older slightly worn chain (0.140 in elongation over 12 links), the chain rides up as shown on the teeth when torque is applied. It doesn't happen in the highest gears, or when it's upside down and I'm adjusting derailleurs. The chain is also not touching any adjacent gears due to derailleur misadjustment.



As stated, I will try ANY reasonable options before replacing the freewheel. I've certainly ridden more worn out cogs without this problem. Should I just try a different new chain? Or is this more seriously worn than I judge it to be?

Additional Pictures added on request:
Need better pictures to get a clear idea as to what is going on here, but assuming that the chain tension is good and the derailleur spring is okay, I'd check to make sure your derailleur hanger is straight. Especially on older derailleurs, this can allow the chain to be received by the cogs at an angle whereby the cog above and/or cog below can 'trap' the chain.

Checking the hanger is easiest with the right tool, it's a bit pricey ($60 - search on "Park Tool Derailleur Hanger Alignment Gauge - DAG-2") so best bet would be to hit your local bike shop and have them lend a hand.