Sorry to hear about your back pain Ed, but could it be the different saddle? I switched from a composit to a vulkor and had all sorts of issues that I couldn’t explain as the set up was to the mm. In the end I’ve moved my saddle back a bit and nose down and it’s sorted my issues. Despite only being a little bit wider I felt I sat in a slightly different place which meant measurements weren’t comparable between the two.
Sorry to hear about your back pain Ed, but could it be the different saddle? I switched from a composit to a vulkor and had all sorts of issues that I couldn’t explain as the set up was to the mm. In the end I’ve moved my saddle back a bit and nose down and it’s sorted my issues. Despite only being a little bit wider I felt I sat in a slightly different place which meant measurements weren’t comparable between the two.