mrw1986

iTrader: (4)

Hey guys,

I purchased a second-hand RDX PHI 08 and I'm putting an EZRUN brushless setup in it (http://www.hobbypartz.com/ez-60a-rc-...ar-system.html) and I was wondering what gearing you would recommend. I'm not going to be racing the car, just bashing it on tennis courts, etc. My main goal is to make sure I don't overheat the motor/esc. Would running a 20
T-23T pinion with the stock gearing be ok?

I'm running a Gens Ace 5000mah 40C 2S Lipo for my battery.

I'm just getting back into the hobby after numerous years (when I left ESC's were still "new" tech).

Thanks!
Matt

Hotbodiesd4

hi there,give it a run with the current gearing now and check temps of motor and esc every 2min.They should stay below 90 degrees celcius.If its cold or not close to it just repeat the process and change pinion untill you get the speed and temprature you want.but remember timing and punch mean heat.

mrw1986

iTrader: (4)

I don't have a pinion yet, would a 20-23T be suffice?

Hotbodiesd4

whats your spur gear size? and google you cars name and look for its internal gear ratio and post it up.

Lazer Guy

iTrader: (1)

Matt
Your motor can run hot if the pinion is to big or to small.
Your ESC will ONLY run hot if your pinion is to big.

To find the sweet spot gear so your motor and ESC are the same temp.
You need a temp gun, your finger will not work, drive for no more then 3min. at a time until you get your temps in the ball park.

I find it best to start with a pinion that is to small.
If you start with a pinion thats to big your motor and ESC will both run hot, that makes it hard to see whats going on.

I hope that helps you understand how to get to the right gearing as fast as possible.

mrw1986

iTrader: (4)

The car has a 78T spur and an internal drive ratio of 2.00:1.

KiDD3

iTrader: (6)

http://www.comeseethis.com/gearing/Default.aspx

mrw1986

iTrader: (4)

Ah ok, that makes sense. So 90C should by the highest I can go comfortably? I have a temp gun already I'm just waiting on my radio to come in the mail to get this car going

Lazer Guy

iTrader: (1)

I really can't tell you how high is to high some motors and ESC's can take more heat then others.
In most cases the cooler the better if you want your stuff to last

PS
That motor you linked to is a 6000kv.
On two cell lipo's thats 44'400 rpm.
Your going to need to start with like a 15t pinion or even smaller.

mrw1986

iTrader: (4)

I tried a 16T and it stripped out my spur. I just couldn't get them to mesh properly. Should I try a larger spur? Maybe 100T with a 23T pinion or something?

Lazer Guy

iTrader: (1)

Yes.....It's much harder to set the mesh with smaller pinions thats for sure but lots of guys do it without any trouble, it just takes more time to set it right.
I don't like using small pinions ether so I use the largest spur I can get in my car.
I use a 114 spur with a 24 pinion but I had to do some grinding to get the 114 to fit.