My Chpt3 (v2) has now got the lowest gearing I can wrangle. Aside from various bits to lower the weight, I’ve tried to retain the Chpt3 look but keeping the gearing as low as possible. My 9speed setup of 38T chainring & 13/15/18T cogs a few years ago was very effective but with the lowest gear being only a smidgin below my 7speed lightweight, the porky Chpt3 needed some tweaking.

In theory, an X4UniBody cassette in the BWR wheel should be a simple 12speed upgrade, with BrommiePlus providing a 4speed pusher & shifter conversion. However the big 21T cog didn’t mate well with the pusher capability & the result wasn’t ideal; workable but not so livable?

Upgrading to 15speed now provides the ultimate gearing combo to help my weakened climbing capability, via an X5UniBody cassette (11/13/17/21/25T) & with H&H derailleur & sequential shifter. The component weight comparisons balance out on aggregate & the Chpt3 weight remains at 9.8kg with the GI range now 90-16.