I have looked on here thru the search tab for gps proven speeds for the summit...i can't find them entering key words. I have seen speed charts of what things should do, but I am going to gps test several gear mods. the pinion gears I will us are 14t(stock), 18t, and 24t. The spur gears I will test are 68t(stock) 65t, 62t, and 54t. I am looking for a good set up with my MMM motor to get good high speed crawling in low gear (I crawl over long rolling grass and big rocks), and get 40-45 mph in high gear.

I test with a garmin 765t mounted on top as pictured

here is what I have found so far.
low gear: high gear:
8 mph stock 16.8v / 21 mph stock 16.8v
12.1 mph mamba monster (14t/68t) 16.8v / 27.5 mph MMM (14t/68t)
14.8 mph MMM (14/68) (2)3s 5000 mah lipos / 38 flat mph MMM (14/68)(2)3s

now thats with stock gearing, crawls great tons of fun. As soon as I receive the rest of the parts I will add to the post. I could not believe the difference the dual 3s lipos made, at 1st I thought I had a bad motor when the speed with 16.8v only went up marginally....more to come if warranted.

next I will test the 18t/68t, then the 24/68, then move to a different spur with the 14t pinion and then the 18t pinion and so on. let me know if I should continue or am I just waisting my time.