Originally Posted by
prem205
Doubt it. Was working fine on old 6 speed freewheel. Just converted to 700c so i bought these wheels used. Its 8sp and rear derailleur also shifts through all 8 gears fine.
Could be a problem with the used 700c wheel freewheel/cassette being worn. The previous owner let the chain "stretch", and the cogs wore to the elongated chain. Then when you put the wheel on, these cogs no longer matched the chain. Your description of chain skip while under load is indicative of an unmatched chain and cog set.