I use 2 near identical bikes most often. Both were flat bar road bikes, hub gear horizontal dropout and a 3*9 vertical dropout derraileur. Basically same tube measurements.
I converted the 3*9 to dropbar 2*9.
52/39 pulling a 23/12.
I love the combination but I miss out on climbs.
I don't want to change the higher combinations because I have 3+ years worth of spare cogs; chainwheels and cassettes and the gears usually shift between 52 pulling 12-16 on my work ride.
Would 52/39/30 work on a front derraileur to your best opinion?
I'm hoping one of the wrecks has an STI *3 left shifter. A bit of a rat bike but it's efficient.
No sure regarding the mechanical throw of the chain stepping up/down sizes. Can't remember what the initial big chain wheel tooth count was but I didn't move the derraileur to utilize it as a 2 speed.
I'm thinking yes.
If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.