Alan B wrote:My derailleur problem is a 9 speed derailleur doesn't expect a 34 tooth gear in position #4, so it doesn't clear the gear, but runs into the side of that gear. It would handle a 34t gear is position #1 just fine, it is designed for that. But the 6 gear freewheel is skipping the first three gear positions, effectively.
So that is one danger of making a 6 or 7 gear freewheel. The derailleur may not be opened up enough to clear the largest gear if it is made too large.
At least that has been my experience with mine.
Sounds like you need to adjust the tension screw to pull the derailleur away from the sprockets.
There really isn't a "9 speed" derailleur - they are agnostic.
Oh, and yes, the spacing for 6 and 7 speeds is the same. 7 speeds fits in almost all motors, I can't see the reason for going lower.
But a 7 speed with 9 speed spacing would be very handy.