Originally Posted by
fietsbob
Because the seat tube does not meet the BB at a common angle ,
no more than 1 chainring is possible.
...and have a front derailleur to shift gears.
several options : a combination IGH - Cassette rear hub.. 3 by 8..
there are a few internally geared 2, and one 3 speed crank.. still 1 chainring ,
but the gearbox is between the chainring and crank arm ,
so crank can turn at a different rate, than the chainring..
OP is in Florida , a state not known for its hills to climb,
but some hellacious headwinds with named storms..
....
i've put front derailleurs on pedal forward bikes. just weld a post on the bottom bracket at the right angle to hold the derailleur. the last few projects i used a trike hub in the chain line, with a shimano front freewheel cluster, so the the hub still "coasts" for shifting. i guess that would be harder if you can't weld, but i do my welding with a little harbor freight flux welder. great for a hobbiest playing with bikes/frames for themselves.