Hello guys, after buy a small motor (4260 300kv) I want to buy a Sk3 motor, it is cheap and reliable, but I use 6s-And will not change it, 6s is easier- and I think 190 kv for a 16/36 gearing is a bit too low and I will have no high top speed, so I want to know, what is the best kv for 6s? And motor size? Would 6354 be small? And 6364?
6374 for single 245kv
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Thatās 2 votes for 245kv and 6374/single But 245kv with 8s would be worlds better if you can see your way to do 8s
6s/245kv 6174 rpm 8s/245kv 8232 rpm
Plus, more torque and more range with 8s
Yeah 8S is even better and still about 10k under the ERPM limit
8S doesnāt really make sense to me. You lose the convenience of charging/balancing a 6S setup for not a whole lot in return. I say go 6S + balance charger, or 10/12S + BMS.
Iād suggest 245kv to 320kV for 6S. Hobbyking has some decent looking SK3 5055/5065 320kV motors, but they only have a 6mm shaft diameter
Two of these at 6S would be pretty legit Iād think:
Edit: Alien Power Sytstems also has sensored 270kv motors in the 50mm size (but theyāre all out of stock):
http://alienpowersystem.com/product-category/brushless-motors/50mm/
320kv sounds fast but would it have enough torque? Iām asking because Iāve never tried anything higher than 230kv so I donāt know. there are 8s balance chargers available and not too expensive.
With one motor, probably not for any real hill climbing. But two of them should have more than enough power. At 6S + 320 kV, it works out well with common pulley ratios:
Personally I run one 149kv motor at 12S. But I think my next build might be a dual 6S
. . . Edit: One 6S motor might be enough if you max out the amps. At 60-65A, you would be be putting out 1000+ Watts
@jmasta Do u usually put āsuch lowā efficiency?
Im running pneumatic setupā¦ and the efficiency is in about 87-90% rangeā¦
I really thinks 50mm motors are good, but I think theyāre kind small 
and Alien is very expensive, I spend a lot of money there and now I will spend my own money, not my fatherās, so I want to save a bit
@Namasaki @lox897 Yes, 245 kv is a good number, but would it be possible to run with a 185lbs person? (Not me, Im 110lbs, but my cousin is heavy)
And other point, 245kv is the point to 6s, but it is a 6364 motor, it length is smaller than 6374, what are the cons of it?
I have been using 70% because it more closely matches my real-world top speed to the estimated āWeighted Top Speedā. Based on torque charts, my motor should have a max of around 87% efficiency. Though 70% in the speed calculator gives more realistic numbers
If you use a big 6374 motor rated for 12S, and run it at 6S, you are throwing away half of your max power output. You might be able to get the same power with a 50mm motor. Similar power for less weight and size?
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Yes, but it can be a problem, I saw guys building skates with 320 kv motor but it was 63mm and I have a 300kv motor that is 42mm and everybody said it will blow! And Jason said āSize is more important than Kvā so I really donāt know, I like Aps motors, they are beautiful, but expensive and I donāt want to spend money on something that I would not use, understand my point?
Yeah I definitely understand your concern. Do you have a link to your motor specs?
I have always run 280 on 6S and it seems to work well.
Well aside from that one UDR board that has a 430 on it. It also works lol.
I have 2 6s builds. I run 260kv on both. One with 40/15 the other with 36/15 pulleys.
Yes, http://alienpowersystem.com/shop/brushless-motors/alien-4260-outrunner-brushless-motor-300kv-1500w/
Man, 40/15 is a big gear ratio, what speed does it goes?
Itās pretty fast, I have to be careful 
. I bout the wheel pulley on a whim. Decided to use it on the most unstable board I have too.
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- MOTOR: 4250
- KV: 300
- MAX POWER: 1500W
- MAX AMP: 50A
- MAX VOLT: 6S
- SIZE: 42 x 60 ( without shaft )
- WEIGHT (g): 0,245
- SHAFT: 5mm with 2mm keyway
Have you considered just buying another one of those motors and running dual motors @ 6S? Build a battery that can give 50A to each motor (100A total) and youād had have a pretty powerful setup. Iād imagine it would give similar performance as dual hub motors
I agree that bigger motors are likely more efficient. I run one myself. However running your 6S motor at 6S will not burn it out in anyway. Two of them would be as powerful my single SK3 6374 at 12S. But they would be much lighter
(490g for 2x 4260, vs 840g for 1x 6374)
90kg, 6s, 245Kv 6364 SK3, X-Car Beast 150A ESC, 83mm Wheels, 13/32 gearing - running good, even on medium hills 
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