I have a 16-1 manual in my feather duster 360-4sp. 225-50-15 tires around 3deg castor. I did have a "grant" tuff wheel that is about 13.5" diam it was a little stiff under 5mph but fine above 20mph. I changed the steering wheel back to a stock one that is around 16" i think. that helped the parking effort a lot and changed my mind about converting to power steering. I like it a lot now.