Originally Posted by bulgie

They don't fit on any GS without modification. Bob Freeman (previously of Elliott Bay Bicycles and Davidson) was the first person (that I know of) to make Rally repops, and he was the one who got Merry Sales to make and distribute them. IIRC, his original hand-made ones were for GS, and since then he has modified the Soma ones to mount to GS. He's officially retired (I believe) but still does this stuff as a hobby.

I haven't seen the ones he's modified for GS, but I assume it isn't too hard. The GS bolt is larger than a NR/SR, so you just need to drill the hole larger and tap it, then drill a small hole for the tail if the spring. A GS has 3 holes for different amounts of spring pre-load, so you could drill 3 (or more), or just one if you know where you want the spring to go.

If you want a stop to keep the cage from rotating too far when the wheel is taken out, then that's another task. But the stop isn't necessary at all while riding, so you can just leave it off. It's just a little more awkward putting the wheel back in if the cage has over-rotated.

Mark B in Seattle