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Brushless Motors: Kv vs. Turns

When you want to buy a new brushless motor for your RC truck, it’s only natural and pretty prudent to want to compare offerings from different brands. The only problem is the manufacturers don’t make it easy. Some market their motors by Kv rating and others use the term turns.

Kv is a measurement of performance. Think of how full-size manufacturers try to impress us with big horsepower numbers. While Kv isn’t horsepower, it does allow us to compare a performance attribute of motors. Specifically, Kv is how fast (rpm) a motor spins when one volt is applied to it. So, in theory, the higher the Kv rating, the faster the motor. For example, a 9000Kv motor would be considerably faster than a 2200Kv motor.

If Kv made us think of horsepower, turns reminds us of displacement. That is to say, like displacement, turns is a physical attribute of a motor. The number of turns indicates how much wire is wrapped inside the motor. A higher turn number means more wire which means more resistance which means a slower motor. So, turns is just the opposite of Kv in the sense that with turns a lower number means faster. For example, 4.5-turn motor would be considerably faster than a 15.5-turn motor.

What it all means
The bottom line is that Kv and turns are two very different things. One, Kv, is a measurement of performance output. The other, turns, is a physical attribute. Again, it’s like comparing horsepower and displacement. Generally, fewer turns means more Kv (speed). It’s just like more displacement generally means more horsepower. You probably know that all engines of the same displacement don’t put out the same horsepower. It’s no different in RC; just because two motors have the same number of turns doesn’t mean they have the same Kv ratings.


It’s unlikely you’ll find an RC company using horsepower to measure performance of its motors. This is because most RC brushless motors produce less than a single horsepower. A better measure to use is watts. You can even convert watts to horsepower.

Brushed and brushless motors are both measured in turns, but the numbers are not directly comparable. That is to say a 10-turn brushed motor does not deliver similar performance as a 10.5-turn brushless motor. For years, a 27-turn brushed motor was the standard of “stock” racing. The new standard is 17.5-turn brushless.


You can find more information on sensorless vs. sensored brushless motors here.

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  1. Matt. Should i go brushless or stay brushed. Im not into speed like a lot of people just do some back yard bashing and some custom work. but everyone keeps telling me i need to go brushless.

    1. I prefer brushless and I generally prefer sensored systems over sensorless. That said, if your brushed motors are delivering enough power for your tastes, run them into the ground. Compared to brushed motors that wear out, brushless motors pretty much require no real maintenance. I’d say brushless is better than brushed, but that better comes at a price.

      1. matt, if the watts given on motor has no relation to the thrust produced by it as u described thn ow can i find the right motor for my VTOL model….or then how can i calculate a motor that need to vertically lift a 1kg weight…..please help me out i am really struck here…..and i need to proof it with formulas….can u help me???


        1. Can’t help you too much with a VTOL model. I’m kinda a RC truck guy. Watts is power and power makes thrust…but a few other variables also impact thrust. If you are not scratch building, I would suggest contacting the manufacturer.

  2. Hello! Great post! One thing to add though. Yes lower Kv’s is not as fast, but it has more torque. More torque is better in situations like a crawler motor. Thanks! 🙂

    1. That is generally true, Austin, and a point worth mentioning. Thanks for commenting. A lower Kv motor will provide more torque than a higher Kv motor at the same current. Motor design, however, is a better way to get power and torque. For example, for a crawler who is seeking lots of power and torque, I’d suggest going to a 4-pole motor and not getting too low with the Kv rating.

    1. Depends more on the actual Kv rating of the motors. That said, say the end rpm was the same, the setups are not the same. The higher turn motor on 3S is far better as it will run cooler and last longer.

  3. I have a semi stock scx10 wanting to do a motor swap but don’t no what motor to get? I like crawling, speeding an trailing through mud, deep water an pulling trailers with 2-3 rc cars on it. any good suggestion i am using a 2 cell lipo 5000mah 25c battery.

    1. personally i have two and for pulling and general use with fair speed i use a dynamite 35 turn motor, for my mudding/water purpose truck i have a traxxas vileneon system, it has amazing speed, has enough power for general use but not he best for pulling if you are just pulling on flat or moderate trail it is great but for actually crawling with more than one car it is hard on the esc and motor

  4. What size motor would you recommend for beginners in rc truck bashing bcuz I live in northeast Ohio climate nitro or electric if electric brushed or brushless

    1. There are too many unknown variables for me to be able to answer that. My wild guess based typical performance is 20 mph, but with gearing and a 3-cell LiPo, speeds could easily be over 30 mph.

  5. Hey guys I’m kinda new at this but I’m wanting to build a road train with 3 trailers. What size motor should I be using as the truck that I’m building will be carrying loads of dirty and I don’t think the standard motor would cut it on a tamiya rc semi truck


  6. I have a question, well many actually. Ok say I have 2 brushless motors of an equal kv rating. One is a 5.5t and the other is a 10t. Would they have the same speed and torque? I run sensorless.would the 10t be able to handle more weight? Would it be better at slow speeds than the 5.5t? I’m getting thento crawling. So I need something that can go slow without stuttering and would like it to also have diecent wheel speed. Would I find my appropriate kv and try to find it with the highest turns?

    1. Crawling and sensorless are not a good match.

      I suggest low Kv, ignore turns, and going with a 3S sensored system with a 3S LiPo. Throw a small pinion on it and you’ll have a great setup.

      In general, when picking a brushless motor, I only worry about Kv ratings.

  7. Hi Matt, very nice article.
    I have a question . What is the difference between a sensored or sensorless motor ?


  8. OK, i have a question about heat. I am going to be picking up a Trophy/stadium truck for my 5 y/o. He will be running in grass and dirt and i am concerned about over heating the motor and /or esc. Any suggestions on a setup for a 1/12 scale 4×4 stadium truck motor? Will running a smaller pinion create more heat since it will be turning alot of rpms or will the low resistance from a smaller pinion be causing less heat build up? Maybe it will balance the heat issue out entirely… i just have no clue since i have not even purchased a truck yet. Thanks for any info.

  9. Hello Matt,

    I just bought a TFL Bronco. What electronics do u recommend? (Rock crawler Motor with lots of torque but decent wheel speed, high torque servos,radio, esc, etc.). I will be using a 3 cell LiPo battery and would like to run some waterproof components.

    Thanks, Jeff

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