Higher pinions = safer MMM's? Or no? Someone's lying....

[J57ltr]

Originally Posted by RC-Monster Mike

It conclusively answers the question - read it again:
The question was weather higher gearing with larger pinions = death to ESC's
The conclusive answer:
In 99% of the cases, that is exactly true. Smaller pinion = less ESC stress.


While your back EMF question may be a point of confusion for you, Freezebyte's questions was conclusively answered. Smaller pinions = less ESC stress.

Regarding the higher rpms with a lower pinion yielding higher back EMF - not sure I buy it. On a given voltage, the rpms of a given kv motor will be the same, regardless of the pinion installed on the motor shaft. If braking from a given vehicle speed - yes, the smaller pinion will have had to be rotating faster(if everything else emains the same) to achieve the speed, but the mechanical advantage of the smaller pinion is still there on decel as it is on accel, so less "force" on the motor shaft proportional to the increased speed(less motor current to achieve the higher rpms and vehicle speed and less "reverse current" to slow it). A 10 pound truck requires x amount of braking force to stop in x distance, regardless of how the force is applied(high rpms with high reduction or low rpms and low reduction). Force = force, doesn't it?

"the mechanical advantage of the smaller pinion is still there on decel as it is on accel, so less "force" on the motor shaft proportional to the increased speed"

The mechanical advantage is higher on the motor during braking with a smaller pinion so there is more force (energy) being generated during a stop. Think about this, I don't know if you have ever push started a manual transmission but you don't do it in first gear you do in in second. the reason is that in first this has the numerically highest gear ratio and is very hard to get started. Why? Because the load is super high when you pop the clutch (slam on the brakes in RC). You are basically swapping the gear ratio when you are braking, this is what I am asking. Could this be a part of the problem (ya, ya the batteries).

We are not talking about controlled enviroments here these things are being handled (put under stress) by a lot of people that don't have a clue, they are in every hobby, it's just the way it is. No one is doing a test where they are topping the truck out and comming to a marker, applying maximum (impending lockup)breaking force recording the results and doing the same for the other pinion and calculating what they need to stop in the same difference. I haven't put the math to but I see your point. But I also see that there a difference, a force over time difference.

Besides as I see it since Patrick quoted me it was a response to me and not Freezebyte.

Jeff