Originally Posted by tigerdog

The issue is that with a freewheel, the drive-side wheel bearing is mounted inboard on the axle, away from the dropout. As freewheels got wider, axles bent in the middle. That's one big advantage of the freehub design - it allows the drive side bearing to be located near the dropout on both sides. Because of this, freewheels typically maxed out at 7 speed. Sachs made some 8-speed ARIS freewheels but they gained the reputation for causing axles to bend, and never gained traction in the market. A better 7-speed setup might make your shifting happy and retain the vintage character of your bike.