Hi,
I'm working on an old 5 speed bike with an axle mounted rear derailleur. When the chain is in the small cog and you apply a fair amount of force to the pedals, it skips. I have tried two different freewheels with the same result. I cannot get it to skip when the chain is in any other cog on the rear, only the 14 tooth cog. When comparing the derailleur position to other bikes, it seems to have fewer cog teeth engaged in the chain. Approximately 6 full teeth are exposed while others seem to leave only 5 teeth exposed. I've sized the chain properly. We have tried watching it to see where the skip is taking place, but it happens too fast. I did notice the lower wheel of the derailleur bounce when my partner was riding it, but still can't determine if the chain is slipping. Honestly, it feels like it's coming from the crankset, which has also been replaced. It's a square taper spindle, which looked fine when I replaced the crankset. At this point, I'm just out of ideas. It seems like the top wheel of the derailleur should be farther forward towards the front of the bike, as well as closer to the cog wheel, but there is no b adjustment.
Any ideas would be greatly appreciated.
Thanks!
Jon