# Need gearing ratio for Mamba Max 5700kv in Associated SC10



## Guest

Trying to figure out this brushless/lipo stuff is killing me! I would consider myself very experienced back when I raced alot 5 or 6 years ago. I built my own track and several trucks recently. I've got an Associated SC10 that I have no idea where to start on gearing the thing and can use some help. First of all gotta figure out which spur gear to use. 87 or 75. Then from there need to know a good starting pinion gear size. My track is dirt offroad. Here is what I purchased

Castle Creations Mamba Max Pro with 5700kv motor
Lipo battery 3S1P 11.1V 5400 MAH. Burst rate 30C

If I sound stupid writing the battery/speed controller statistics it is because I am ignorant as to what most of these mean. I understand the output voltage and battery capacity. But matching up all the different motor types for gearing with the different batteries is kicking my buttox! My XXXT has a Novak GTB 5.5 in it, I figured that out. But now, instead of 5.5, 6.5 etc, I'm dealing with motor KV. Not sure how to compare the 2 different types. Is a 5700kv the same as a 5.7? Not that they make a 5.7 but you know what I mean. The brushed motors and NIMH packs were easy to figure out. The Lipo batteries just throw in another variable with the 2 cell and 3 cell. Anybody with some gearing starting points for this thing would be greatly appreciated! I'd hate to burn it up before I get the hang of it. Thanks in advance for any advice.
Al (Alzado77)


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## Lazer Guy

Maybe I can help.
I have been using the Castle 1/10 stuff for more then 6 years.
Right now I'm running the 5700 on 11.1 in my TC racing on road.

Using the KV of any motor will tell you the RPM.
11.1 x 5700kv = 63'270 rpm
7.4 x 5700kv = 42'180 rpm
7.4 x 9000kv = 66'600 rpm

I don't like using small pinions so I always start with the biggest spur that will fit in my cars,trucks & buggy's. I some times need to grind and file here and there to get the big spurs to fit.

Your motor will get hot if your pinion is to big or to small.
Your ESC will only get hot if your pinion is to big.

It's better to start with a small pinion, big spur and 0 timing, from there you drive for 3min. and check your temps. 
You want to gear so the motor and ESC are the same temperature (150* to 180*) will put you in the ball park. 
From there you can add timing if you want more speed well watching your temps for a 3min. run. 
Adding timing will heat up the motor so keep it under 200*.

I hope this helps you.


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## Guest

*Thanks!*

Thanks for that info. That definitely added to my limited knowledge and I should be able to figure out a good starting point. I guess I need to purchase some sort of a temperature gun. One of the few items I don't have.


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## 4ThePinkRacing

i know it was said 150 to 180 but i myself stay at 150 or below.. its safety for the motor .. there are many many ideas on this .. so not one is purfect .. 
i find it liek this in computers people what fast computers get a bigger cpu same with RCs want fast get a bigger motor lol 

but a 5700 in a sc10 is real good fast .. good luck with it


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## Guest

*got it*

Got it built. Used a 13 tooth pinion. Seems to be perfect. This thing is what I would describe as "stupid fast". I can't get it past 1/2 throttle anywhere on the track except a 100ft straightaway. And even then it's probably only open all the way for a tenth of a second. How I didn't break anything on this truck I don't know. Looked like Nascar at Taledega flipping down the backstretch!!


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## Al Schwarze

three cell and a 5700kv motor on dirt is over kill x two.. I run 2 cell with a 4200kv in my sc10 and that is more then fast enough...


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## nutz4rc

Al is correct, overkill to max. I run a 5700 in my buggy with a 2 cell and can't even open it up completely on a 150' straight. I have enough reserve power to pass anything and jump anything. Car is stupid fast and can pull wheelies whenever I hit full throttle and track is tacky.

I would run 2 cell but that is just me.


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## shintastrife

i would say that's that's a good thing you all ways know your can be faster then every one, its just getting to car set up so you dont flip it. cant say to much i run a 6600 kv with a 2c in a evader just b/c its my toy car. running stock gearing temp gets around 180. at the road cross off track track i guess you can say. i dont even get to use 1/2 throttle.


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## Al Schwarze

I have been racing off road for years, and I see it all the time, Now mind you I like a fast truck, Because when it comes right down to it we all want it to be fun, But there is a definite difference between holy crap fun and fast, in any kind off dirt racing especially off road, Control is key, if you have so much power that you cant control it then even though it looks and feels fast your lap times are going to suffer, good laps and a good over all run is determined by how smooth and how consistent your laps are, and it is almost impossible to run good, smooth laps when every time you touch the throttle your spinning the tires.. LOL Trust me I know.. LOL you can turn your punch control up on your mamba pro, But the best thing you can do is go to a higher kv motor(or higher turn motor depending on the brand) so that you can pull full throttle on the straights, It may not be as fun but you will run a lot better over all.. I guess it just comes down to what your looking for. You can have way to much power and do donuts on every corner, LOL Or you can go with just enough power and finish better and maybe even win once in awhile.. 
Just my two cents worth....


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## bigmike22

Lots of guys show up and run the same setup as above and guess what, there are several of us that beat them on a regular basis on a huge outdoor track with just a 17.5 brushless setup. They have no control of it whatsoever. And on any of the tight parts of the track we are alot faster. The only advantage they have is the one long 150ft straight away the rest of the track my 17.5 is superior.Learn how to drive first then go for the power till then you will never fiqure it out.


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## nharkey85

bigmike22 said:


> Lots of guys show up and run the same setup as above and guess what, there are several of us that beat them on a regular basis on a huge outdoor track with just a 17.5 brushless setup. They have no control of it whatsoever. And on any of the tight parts of the track we are alot faster. The only advantage they have is the one long 150ft straight away the rest of the track my 17.5 is superior.Learn how to drive first then go for the power till then you will never fiqure it out.


agreed. ran a 13.5 class and a stock/17.5 class last weekend. lap times for the 13.5 truck was no faster than the stock (RTR) truck. it was fast down the 2 straights, but there was tons of bumps, jumps, and corners.

its a tortoise v. hare situation. slow and steady (smooth/consistent) will prevail


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## Lazer Guy

alzado77al said:


> Trying to figure out this brushless/lipo stuff is killing me! need to know a good starting pinion gear size.
> Castle Creations Mamba Max Pro with 5700kv motor
> Lipo battery 3S1P 11.1V 5400 MAH. Burst rate 30C


You guys are right, a big motor can be a big disadvantage.
IMHO
First you would have to be able to gear so your at full speed just passed the 3/4 point on the straightaway with everything at %100, that may not be possible with this combo in some off road applications.

If your pinion is to big with high KV BL motors you'll just spin the tires more not less, they draw more amps, make more power and everything can get hot.

With brushed and lower KV BL motors you can load them down with a big pinion and spin the tires less.

PS :thumbsup: I would be saying gear up/gear down but some people can get that backwards


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## markd5469

We have a class at our dirt oval for those who want to run mega-motor and 3S lipos. We call it Crazy-A** Brushless. It has become Novice on Steroids now. As soon as they break out of novice, they buy a big motor and big battery and try to zoom past everyone. The LHS loves it, because there's lots of parts being bought.

However, the winner is usually someone with a lot less motor, and good handling, who missed all the big wrecks.


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## djcyder

and sc10 running a 13/87 would be horribly under geared for a 5700 kv motor. That puts your FDR around 17.4:1 Idea FDR is around 11.8:1 which means you should be running closer to a 19/87 however I don't know what spur gear you are using.


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## J Blaze

every body needs to lighten up a little.
(big mike ) 
I think its fun as hell to run a big motor
5700 on 2 cells in duratrax 2wheel drive buggy
super fast alot of fun !!!!


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## bigmike22

J Blaze said:


> every body needs to lighten up a little.
> (big mike )
> I think its fun as hell to run a big motor
> 5700 on 2 cells in duratrax 2wheel drive buggy
> super fast alot of fun !!!!


Oh no doubt the big stuff is a blast but i have been top 5 all summer on the bigger outdoor tracks and im only running a 17.5. Some of the guys like rusty and fred can handle the power. Lenny to btw. But the rest that show up with the big stuff i can hand them there butt on a platter with my sc10 with 17.5. They never learned how to drive there trucks before they put the big motor in it, what makes them think adding that much power is going to help them?

Ill see you on the track soon blaze!


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## J Blaze

bring it lil mike. lil george is waiting 4 ya. 
thats funny right their.


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## bashslash

i run the 5700 in my sc10 and love it. I just turned up the punch control and got some good tires im running a 2s lipo and 87/19 gearing it works pretty well and i still get lots of punch for the jumps and straight aways.


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## rcbeagle

Spur Pinion Final Drive Notes Gear Chart 
72 16 11.7 Slightly over geared by 0.85% View Chart 
78 17 11.93 Slightly under geared by -1.1% 
84 19 11.49 Slightly over geared by 2.63% 
87 19 11.91 Slightly under geared by -0.93 
Hopfully this will help


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