91 and up, but never 100% across the build. You can use non-abs, and if you want to keep the ABS, put the GVR4 rings onto the 1g hubs. If you have a 91 GVR4 that uses 2:1 Front/rear sensor ratio, you need to adapt somehow anyway, since all 1g use 1:1 ratio Front/rear.
I have parts if anyone needs them.