Convert Sachs 8sp freewheel to 7sp?
 

I have a Sachs 8sp freewheel. My understanding is that it's possible to convert it to 7sp. Before I start to tear it apart and screw something up, is there a simple explanation? Do I need to source any extra cogs?

If the outside sprocket just screws into the second, a pair of chainwhips and some grunting will do the trick; so that part is simple.

After that you really ought to re-space the hub; get that right side as close to the dropout as you can. You may well have an axle that is too long, so substituting a shorter, or the procrustean method will fix that.

Thanks. The freewheel isn't on a hub, so that's not an issue. So, just unwind the outer cog? That sounds easy enough.

Yes, I don’t remember how many of the cogs thread on, but it’s at least the first two.

Yep, just unscrew the outer cog and you have a 7. I have a pile of outer cogs from Sachs Freewheels that have never touched a chain. Used to buy 8s when they were available and they became 7s before they ever went on a bike.