*gear reduction unit

[wolfws6]

So I have decided to run a 55t motor and 6 tooth pinion. I need to slow the truck down but I need a lot of extra torque over the stock motor to pull this massive 45lb toy hauler trailer around. BUT,,,,,,, Here is the magic question????? How much slower will it be vs 55t motor 6 tooth pinion and stock tires vs low pros? I'm running rc4wd low pro tires. They are 73mm tall vs stock Tamiya's 83mm. So theoretically it would be even slower maybe to slow. I want realistic speed more torque. Any suggestions Please help!!!!!