The Microshift thumb shifter I bought on e-bay arrived today. I mounted it on the handlebars and adjusted it to the indexed setting. As soon as I had done that, I realised that it wasn’t going to be for me. Even without attaching the gear cable I could tell that the distance the thumb lever needed to move would make it too awkward. Had it been a mechanism with a return spring which moved the cable one gear at a time, it would be ideal but this needs to move to 10 separate positions so the lever moves over 180 degrees in relation to the body. In some gears the lever will interfere with my brake and the bars don’t have space to move them apart. It’s a pity as the quality of the build is much better than the plastic Shimano style shifter.

I’ve ordered another shifter, this time an XTR one and will stick with that. You live and learn.