mamba max very weak braking...why?

[J57ltr]

What is your gearing? 87/19?

Jeff

[blueb8llz]

Originally Posted by J57ltr

What is your gearing? 87/19?

Jeff

no, try 86/25 hahah i told you i was geared super high.

[J57ltr]

It will go faster if you gear it down (numerically higher). I have a friend that has the same combo I have and he will eat my lunch if I am geared too high. You are geared for about 75mph, it'll never get there. For sure this is the reason you are have weak brakes. If my friend is geared 87/15 and I am 87/20 I can't even come close to catching him. We both run A123's and the 7700 in a rustler. It won't even pull a wheelie with that gearing in my truck
(87/20) Even his top speed is faster than mine if I am geared too tall. And I usually have to have 100% for the braking force and it will slow the truck from top speed but as the truck slows the braking force drops.

Jeff

[BrianG]

I agree. When geared high, the motor is turning less per mph so the coils/magnets will have far less braking force. I bet you probably have max braking at high speeds only, but then gets weaker the slower it goes. Also, I wonder if gearing so high caused excessive motor heat and the magnets are starting to weaken?

[blueb8llz]

yup, i think you guys are correct! i am geared so high its actually making my truck slower. i was wondering why my rusty seems so slow. ive had it for a 6 months now, but it only has like 45 mins run time hahah. never really have a chance to mess with it since im usually busy having fun with my other trucks.

it seems as though its only going about 45mph. and your right, it doesnt wheelie even with the slipper at the tightest. i would drop in a smaller pinion right now, but the rusty is outta commision due to some soldering i need done with the motor bullets. during the last run, i guess it got soooo hot, it unsoldered one of the motor bullets. when i get the time to solder it back, ill let you guys know the results with the smaller pinion.

[BrianG]

Running when geared too high and/or with a partially demagnetized motor will harm the ESC and even your batteries. The coils need the rotor spinning to develop back-EMF and if the magnet is weak, those coils are looking more like a straight piece of wire.

Unless the solder joints were done crappy, desoldering wires is a sure sign that wayyy too much current is being pulled.

[blueb8llz]

so i finally got the chance to solder the motor wires back (been very busy and non rc status) and the ones that said i was geared too high, was correct. i was geared 25/86 with a 6900kv mamba in a rusty with stampede tires/wheels.

i put in a 19t pinion and it has maximum braking now. itll do those 180 to 360 degrees spins when i brake now .
but the top end still looks to be about the same speed. but the low end is defininetly punchier. but still no wheelies.

im gonna try a 16t pinion and see if that will make my top end quicker. if what j57ltr is true about gearing lower for more speed (two post above) then it should do the same for my rustler.