Hi Rob just tried a 80t motor on my chassis ,it has really slowed it down but has tons of torque to climb looks about right for what I want under the DUKW, will have to fit shorter shocks need to remove the shock mounts to fit the DUKW hull 70mm ,but its up and running with new chassis and motor have refitted the original body to run around and test out . Have you thought about adding a servo to operate the two speed gearbox .
I could fit the gearchange servo but it goes pretty well with the 55T motor and all of the lowest gearing options. Will take it for a run through the woods next week to find out. Had a few car problems recently so haven't been able to travel far.
First was outdoors, at which point I discovered that the 55 turn motor wasn't being powered enough by the standard esc.It just ran out of power when doing standing start steep climbs.
I then fitted a Quicrun 1060. This allowed my to use my programmable tx, so I altered the throttle curve to give more power at low revs, and presto! It now climbs like a mountain goat, despite the weight. It also has a drag brake now which is a great help.