With 26" wheels my Rohloff gives me a 17" low gear. Rohloff doesn't recommend a gear ratio between front and rear of 2.5 to 1 for GVW above 100 kilos. I have a 50 tooth up front and a 20 tooth in the rear. A Schlumpf Mountain Drive might solve your problem. They are less expensive than a Rohloff or Pinion. You could have 727 percent range. Would a gear inch range of 15 to 110 work for you. The crank is an internal 2 speed. If this interests the OP than look into it. Cycle Monkey is a US importer for the Schlumpf cranks. Recumbent bicycle shops also may have them.
Last edited by Rick; 09-10-21 at 01:35 PM.