With 52/39 on the front my 52 year old legs really need 26 on the back for steep gradients (and Bison Hill is part of my regular run with ramps up to 21%). But with three sets of wheels that gets pricey with the 26t sets fetching decent money and no availability for single sprockets. (I want each wheel set to be ready to roll. Otherwise I turn up late!)
Time to get creative then...
A small speculative investment in some odd 9sp cogs, including one 26t, suggested that the tabs that engage with the freewheel on the 9sp cogs have more metal than the 8sp. Ten minutes with the Dremmel and a result.
The 9sp sprockets are visibly thinner than 8sp but I'm just running the 26t and using the 8sp spacers with the other seven 8sp cogs and it runs fine with positive changes up and down.
I dare say others have tried this too but haven't read of it elsewhere so it maybe useful for someone.
In the shed:
Raleigh Team Pro - SB1988
Ribble 531C - "The Real Steel Special" - custom paint and Shimano stuff
GT Hardtail - Y2K frame plus hand-me-down parts
Specialized Transition Expert - modern aero TT rocket