When touring we use a 36t cassette and 26t small chainring and a 35mm tire on a Co-Mo Speedster. I think our low speed is around 5- 6 mph. Working hard on a steep grade at these low speeds with a touring load requires a lot of small handlebar corrections to keep us pointed straight. But certainly not uncontrollable.

Non-touring and unloaded we run 27t cassette with 26t chainring and 28 mm tires.