OMG Steve! Thank you!!!!!
I just did this to one of my monsters last night. I layed my gears out just as you have done. I used all green gears, a blue zz gear, and a green motor with 7 tooth pinion. It took me about an hour and a half to get all the gears to line up perfectly, but was well worth the effort. With all gears a aligned (sp?) correctly, my monster is quiet as a mouse. And speed? Well lets just say I timed how long it took my truck to go 10 feet, and are you ready for this? It took my truck 63 seconds to drive 10 FEET!
That's not all. My truck will climb a 55 degree angle! I put double sided tape on the tires and managed to peak at 60 degrees! I'm watching my truck climb this thinking to myself "I can't believe this is possible!". I'm sure if I was to put more weight in my monster, it would climb even steeper angles because I pushed it to the point where the wheels would spin. I don't think it would spin as easily if it was heavier.
I'm not sure what my total gear ratio is, but this thing is now a true monster. (all i have to do now is make it articulate)
Props to you Steve for sharing this information!
EDIT: Okay; I just used chilli_mp138's formula posted above to calculate my new gear ratio. I'm getting 287.73:1! Can somebody tell me if this is right? That just doesn't seem right. I think I did the math right. Again my gear setup is as follows and in this order using chilli_mp138's formula,
Gear Set One
input (motor gear--MT pinion) 7 teeth
output (MT green gear) 32 teeth
gear ratio = 32/7 = 4.57:1
Gear Set Two
input (MT green gear) 8 teeth
output (ZZ blue gear) 18 teeth
gear ratio = 18/8 = 2.25:1
Gear Set Three
input (ZZ blue gear) 6 teeth
output (MT green gear) 32 teeth
gear ratio = 32/6 = 5.33:1
Gear Set Four
input (MT green gear) 8 teeth
output (MT green axle gear) 42 teeth
gear ratio = 42/8 = 5.25:1
Total Geartrain Ratio
4.57 x 2.25 x 5.33 x 5.25 = 287.73:1
And if I had a 6 tooth pinion - 335.58:1