Originally Posted by LouDawg

I just ordered the RCShox center diff for my truck and was wondering if anyone has any experience with it yet. It looks awesome on the vids Mantisworx put up.

Originally Posted by MantisWorx

i dont change gearing for tracks, the small track and the big track both have a 15/60. running smaller pinions on brushless motors will actually give you less punch. My tekin ran much hotter with a 13t than it does with the 15. maybe Krio can chime in on this. Watch this video at 2:40 this is not accelerated video it is 1:1 watch the accleration mid straight! I can run down e buggies
http://www.youtube.com/user/Mantisworx?feature=mhee

Originally Posted by MantisWorx

EXCELLENT MAN, THAT IS BRILLIANT!

Originally Posted by symmetricon

i have been using one since testing, and it works great,and I have not had a single problem with it! Once you try it, you wont be looking back!

Originally Posted by MantisWorx

i run 15/60 which is about the same, i found it harder to drive with the smaller pinions. As Krio just explained go up to 15 to tame it down and give you a linear powerband. i dont see a reason to ever run a pinon smaller than a 14 especially with a 62. He also noted that its not the size of the track that matters, its the layout. Honestly i dont even think that matters , my turn exit acceleration is staggering therefore it wouldnt make sense for me to drop a pinion as i would lose acceleration.

Originally Posted by Krio

Unfortunately you won't find the clutch basket or a chassis brace on amain. If you are looking to go the absolute cheapest/cost effective rout pick up some Garodisks from here http://rcshox.com/shoxshop/catalog/p...products_id=48
Then send a PM to CoyoteSlash here on RCtech, paypal him $15, and he'll send you a carbon fiber tube brace. I got one from him and it works perfectly.

Assuming you get the 4000 kv, grab pinions from 14-16 and you should be good to go.

Originally Posted by LouDawg

I just ordered the RCShox center diff for my truck and was wondering if anyone has any experience with it yet. It looks awesome on the vids Mantisworx put up.

Originally Posted by tom2tone

How many of you are running the Tekin pro4 4600kv? Is it a good choice? I'll be racing only and in 2 different indoor tracks. One is very small and the other is medium size. I'll be planning on racing it outdoor on a few large tracks.

I'll be ordering my kit either today or tomorrow, are there any other MUST haves to get? Otherwise I need to keep it to a minimum. Plus I was thinking I should get some pinions...any thoughts?

Thanks!

By the way this is my first AE vehicle so I'm not very familiar with them and have no other parts etc.

Originally Posted by Krio

I have my 4000 geared 16/62 with little timing (just enough so that I have some more very top end rpm to use to correct the car mid air, nothing that really takes affect anywhere on the track) and it absolutely rips. I've repeatedly had people use this exact word to describe my car on the track: Missile.

Here's what I am going to copy to a word document and paste whenever this question comes up again. Get ready for a long read. lol

A dissertation on temps and torque with respect to gearing. Please read Heat and Torque separately as you must balance the two:

Heat:
Follow this if you can and realize this is for illustration purposes only for the general audience. Trolls can nitpick the exact formulas another place.
Heat = Energy
Energy = Power x Time
Power = Watts
Watts = Volts x Amps
Volts = Amps x (Resistance Squared)
Watts = Amps x Amps x (resistance squared)

Going back to the top and putting it all together:
Heat = (Amps)^2 x (Resistance)^2 x (Time)

Resistance comes in two forms:
Resistance as we know it and can measure with a $5 ohm meter from one point on a wire to another with no voltage change.
And Impedance, better known as electricity's unwillingness to change direction. This comes into play as the rpm increases and the esc keeps changing the coils being fired to rotate the rotor.

At 0 rpm there is no impedance, just resistance so the total resistance is very very low. Hence why these motors will pull 100+ amp spikes at start up. Looking at our Heat formula, resistance is low and amps are crazy high. That's going to equal a lot of heat over time.

At high rpm you may only be pulling 10 amps cruising around a high speed sweeper, but the Impedance at high rpm is high so that will also equal a chunk of heat over time as well.

What you find is that most motors are most efficient roughly 50% of their max rpm. If you gear your truck low so that you are constantly in the upper 70-100% of their rpm range you are not running very efficiently. If you are geared high so that you are putting around in the 20-40 range all the time you aren't running very efficiently either. Gearing up or down (strictly for heat) should depend on how flowing the track is, not necessarily for size. Tons of slow 180s and you are overheating? Gear down. Fast flowing layout and you are in the upper rpm range a lot and overheating? Gear up. Track with both? Good luck. lol

Now for part 2, Torque:

Motors make peak torque at 0 rpm. Motors make 0 torque at peak RPM. Without dynamic timing, this is usually a pretty linear slope from max torque to no torque.

Time for another math problem:
Assume a car with a 10:1 transmission ratio. The transmission divides rpm and multiplies torque.

Assume a motor with 100 torque units at 0 rpm and 0 torque units at 20,000 rpm in the previously assumed car.

Assume at full throttle (20,000rpm) the car goes 20 mph.

At 0 rpm (and 0 mph) you have 1,000 torque units at the wheels. Nice. That's a lot of torque. At 20,000 rpm (20 mph) you have no torque. Nice. You've topped out and are flying down the straight. It's safe to say at 10,000 rpm (10 mph) you have 500 torque units. Half rpm, half the available torque.

Now lets gear down for "more torque". Lets go 15:1. Your car now tops out at 13.3 mph and has 1,500 torque units at 0 rpm. LOADS of toque. However, how much torque will you have at 10 mph? 10 mph is 75% rpm, so you have 25% torque. That gives you 25 torque units multiplied by the 15:1 gear ratio which gives you: 375 torque units. We used to have 500 torque units at 10 mph.

"What the heck" you might say? "I thought we geared down for more torque" you might say? We did, but not at 10 mph. You have more torque down at 0 to 5 mph than you did at 10:1, but at 10 mph you have less. Our cars are rarely going less than 5 mph, so gearing up from 15:1 to 10:1 would give you MORE overall torque on the track than gearing down. I think it's safe to say most longer jumps are hit at 10+ mph, so if you wanted more pop off the face of a certain jump you hit at 10 mph, gearing at 10:1 will send you further than 15:1 would.

Again, this is still a balancing act with heat as gearing up for more torque at 10 mph may put you in that low rpm range most of the time. That is why you must think of these two categories separately gearing for torque/speed first with the ceiling of heat/rpm forcing you to compromise.

Originally Posted by Ivegotklas

Let the Trolling Commence.

Heat = Energy

True

Energy = Power x Time

Energy is the change in work over time or E = dW/dT or E = Delta(W)

I fully understand that. I oversimplified my statement for the sake of argument. Watt hours are a measurement of energy. Watts are a measurement of power and to get that to energy you multiply it by time (As I assumed a steady state)

Power = Watts

True

Watts = Volts x Amps

Yes P=I*V (Oh two right good job)

Volts = Amps x (Resistance Squared)

Correct, I made an error there. Resistance shouldn't be squared. I meant to write Watts = I^2R. I wrote that all in 10 minutes and didn't check it. I'll go fix it.

Ohm's Law V=I*R (Almost right but when did almost count)

Watts = Amps x Amps x (resistance squared)

P=(I^2)*R (Almost correct again good sir)


Going back to the top and putting it all together:
Heat = (Amps)^2 x (Resistance)^2 x (Time)

This is again wrong. You aren't accounting for any physical movement or environmental factors. Yes I agree the current through the motor and the motors resistance factor in but there is much more to it then that.

Exactly why I said don't take them as exact formulas. Yes there is more to it, but that covers the bulk of it.

Resistance comes in two forms:
Resistance as we know it and can measure with a $5 ohm meter from one point on a wire to another with no voltage change.
And Impedance, better known as electricity's unwillingness to change direction. This comes into play as the rpm increases and the esc keeps changing the coils being fired to rotate the rotor.

Resistance and impedence are the thing. Usually in DC circuitry we use resistance and it AC circuitry the term "Impedence" is used. I wouldn't say impedence is electricity's unwillingness to change direction. I would say impedence is the resistance to the flow of electrons. Resistance aka Impedence actually comes in three forms, the resistor, the capacitor and the inductor.

Again, I understand they function the same, but we aren't dealing with a DC motor. These motors are technically classified as a brushless AC motor. The impedance I am referring to is inductance with the magnetic field forming and collapsing resisting the flow of electrons.

Trolling Over

Honestly I am not trying to be a dick here. I was just surprised you didn't Wikipedia this before actually posting it. There was a lot that was wrong with this but I chose not to continue. If you want to learn more about motors and speed controls PM me I can give you some of my old college texts.