RC Gearing Explained - What happens to Torque, Power and Speed
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- Опубликовано: 5 сен 2024
- In this video we get a good understanding of how the RC gear ratio works. We answer questions such as what is the reason for a gear ratio? What does the gear ratio do to power, torque and RPM of the motor? And more!
A transmission in an RC vehicle is quite an important assembly. It allows the designer to better control the amount of speed and torque that gets transmitted from the motor to the output shaft. In an RC car this would of course be the wheels. Not only are gear ratios used in RC cars however, they are also used in RC Airplanes and RC Boats.
The RC gear ratio can easily be calculated. Simply take the driven gear number of teeth and divide it by the drive gear number of teeth. Although using the number of teeth is the preferred method for determining the gear ratio, it is entirely possible to calculate the gear ratio by using a diameter or circumference measurement.
The gearing that you use is also highly dependent on the type of driving (RC Car) that you will do. For example a high speed track would make for gearing that would allow high speeds. A tighter track with a lot more corners would be more suitable with a gear ratio that sacrifices speed for torque.
This video should be a life sticky. It's a shame it doesn't have more views !
I actually followed along with that. Thanks! You explained it quite well. Much appreciated.
I absolutely love these tech focused rev videos, there’s not a whole lot of good videos out there that thoroughly explain the what, how, and why about a given topic. I’ve watched the suspension video, but was wondering if you could do a video on shock piston options, for instance the VRP pistons, or MIP bypass pistons or anything else related to that kind of stuff? Keep up the good work!
Hey Andrew. Thanks a lot for the comment! I can add to my video queue (it's quite long currently), shock piston options.
@@RCexplained love how detailed your videos are what gearing u recommend for my kraton 8s exb with castle xlx2 1100kv I'm mostly a basher no jumping would like 60mph also have fault fans for 1100kv motor
Great video
Thanks for the visit!
All your videos are very informative. So liking this video.
Thank you dynasty4851!
Absolutely amazing explanation. Thank you so much
WPG TNT, Thanks a lot for your comment!
Can you make a video about what to consider when changing spur size vs pinion size?
This!!!
thank you for sharing! - a more detailed setup explanation of what toe affects handling would be very helpful
Hey Bill, thank you for the comment! This may not be the detail you are after as it only covers the topic generally, however, have you checked this video out?
ruclips.net/video/FP1PYg3To6U/видео.html
@@RCexplained yes! not only have I watched it, gave it a "thumb up" as well!
The more I learn about setups, specifically for 1/10 touring cars, the more unsure I become as I started to understand how different settings are affecting each other. I've also watched a series put together by RCCrewChief (you can search them on RUclips). He's the only resource I can find that dived a bit into the science and physics of touring car setup, but not as well-articulated/ explained as the videos you are making. That said, I would strongly recommend this topic for your future videos. It should be very interesting and appealing to all the more serious racers out there who are trying to understand the reasoning behind all the settings instead of just following the experiences or force remembering all the "rules".
Thanks Bill. I will consider your suggestion and see what I can put together. I have a long list of video in the queue however, this would be a fun video to do for sure.
Super useful!! Thanks for simplifying this for a newbie like me. I now know what I’m doing when I’m switching those gear ratios.
Glad it was helpful!
Good stuff! Thanks bro!
Hi :) acoording to what you've said gear ratio is a factor for tourqe, speed, power and heat, will it be no efect to the pinion gear or spur gear size? For exemple does it matter if im getting 10:1 ratio from 18 teeth pinion and 70 teeth spur or from 19 teeth pinion and 74 teeth spur?
If your ratio is 10P / 20S vs 40P / 80S, other than physical size changing there isn't much of a difference as the ratio is identical.
@@RCexplained thank you very much!
Thank you for helping to simplify this for me as I’m trying to find out my ratio for my hpi sprint 2 rwd I understand the ratio for spur and pinion but what if you have two pulleys for the final output would I still multiply the motor and spur with the pulley output
Hey thank you for your comment! If the first pulley is on the same shaft of the spur gear, then you can multiply the 2 ratio's.
Hi Unkrowned Beatz, in a recent upload, I talk about the gear ratio and its effect on belt/pulley. Take a look: ruclips.net/video/8Q-h-3fBfHI/видео.html
Dude. Can you explain calculus to me. Great job!!!
Thank You stillgame!
Great video :)
I enjoy your videos immensely! I am interested in running a TP motor in an Infraction for speed running and would like your recommendation if I will be running 6s and 8s max which KV do you recommend of the SVM motors to run cooler (less stress)? Also, for a bashing motor in an Infraction, what do you think of the Castle 1717 1650 KV motor over the stock motor found in the Infraction V2 6s chassis? I will be changing to a GT body for speed running. Thanks!
Depends on what you are doing. I'd tend to run near the max RPM of the motor and gear according to what speed you are looking for.
I own a first gen 1717 ~1600Kv motor from maybe 2009? It's a solid motor, I'm a big fan of the Castle motors.
Thank you. I just purchased a 1717 and had buyers remorse and thought maybe but much difference than the stock Arrma motor. I appreciate your response as to what speed you run your cars. Your videos are great! Take care.
Nice job. Thanks!
Thanks for the comment!
I have a Arma kraton 8s with xl2 and 800kv motor and a 39th spur and a 30 pinion gear is that a good set up for speed and power.
How did it run?
Hello, i would like to ask
Let's just say i have 2 setup
1. Pinion gear 15T spur 60T with 1000kv motors
2. Pinion 10T spur 80T with 2000kv motors
Beside all that, esc, kit, battery is the same, my question is
Which one is faster?
Which one is more efficient?
Which one has more torque?
Assuming the motors are of the same size just different wind, the higher kv motor will have more potential. This is due to the internal winding resistance being lower than the low kv motor.
With lower winding resistance the high kv motor will be able to draw more current and create less overall waste heat at equal current values.
I have other videos that discuss this in more detail. Search for terms such as torque.
@@RCexplained wow, thank you so much for your reply
Maybe this is because I have trouble with math but, I don't understand why the intermediate gear needs to be eliminated. It seems to me that putting the pinion gear directly to the axle gear would put more strain on the gears' teeth. Wouldn't the middle gear give more even power distribution and in a sense give the pinion gear more leverage in controlling the axle gear?
Gear stress and strain is not reduced using a middle gear.
@@RCexplained, thanks for telling me.
My trans ratio is 3.307 I want to go up from 13t to 14t on my diffs input gear which would make my trans ratio 3.07 how would that affect my car in drag racing? Better take of, higher top end speed etc.,?
I put a 13.5t rotor in a 2.5t motor for more rpm for drag racing. If I use the 2.5t rotor for my 13.5t would tha torque make it faster or should I use a higher turn motor like a 17.5t?
The rotor in a 'spec' 13.5t is quite a bit weaker than a rotor that would be in a 2.5t. The ROAR spec rotor has the same outer diameter at say 12.5mm, but the inner diameter of a spec rotor is 7.2mm where the inner diameter of a mod rotor is 5mm. This gives a max gauss of a spec rotor to be about 1700 milligauss where a mod rotor is in the 2000+ range. A high gauss rotor tends to drop rpm and gain in torque, but you can crank the timing to get the rpm back and it typically results in a more powerful motor. A 13.5 motor with any specific rotor will be faster than a 17.5 with the same rotor. Reference: www.teamtrinity.com/assets/images/Rotor-Chart-updated.jpg
Looking to find a good set up to get more torque when im racing people burn me out of the corners an its a oval track and im running a stock traxxas slash 2wd if anyone has any advice please speak
Hello, great explanation, but I’m still lost with my set up.
Current have an Arrma Senton 550 mega, converted to brushless.. the stock gearing was 17t pinion to a 91t spur(48p) .
I recently upgraded the spur gear to the metal 57t(32p) now running a 20t pinion.. so my change was 17t-91t to 20t-57t.. I’m trying to replicate that stock gearing configuration, should I go down in size on the pinion? Thanks
Stock gearing 91/17 is closer to 57/10. Try something closer to 10T that fits.
@@RCexplained thank you!
Hey @RCexplained, how do high powered escs work. What I mean by this is how could I use my homemade Arduino esc, and tweak it so it could output upwards 200 amps? Would you use capacitors? Transistors? I’ve built a simple esc but I want to make it so I can run my powerful motor. I’ve been stumped on how to do this for a while now so some feedback would be greatly appreciated. Thank you
There's a few websites out there that cover part of ESC design. I do believe what you are looking for is within the FET's of an ESC. This is what handles the power capability.
RCexplained so the FETS contains 6 mosfets correct? Does this mean that the mosfets can handle the current?
@@caleb1951 they are responsible for handling the current. See if you can find a website that gets in to the details a bit deeper.
Can you do a video and show all your cars
Hi Mason, if there is interest I could make a video showing all cars. I believe they all have appeared at some point or another within the videos.
I like what you are saying and doing for us racers these are very good thought out videos, thanks! But I'm wondering how do I gear my car for the track I am racing on to get the sweet spot? I race oval the tracks vary slightly, run line for my home track is 144' I run 21.5 brushless motor which has a current of 2.11 and a KV of 2178. Right now I have a 59 pinion and 96 spur gear does this calculate about right for my track? How do I calculate gearing using the different run lines say 150'? Thanks for your input and I will watch all of your videos!
Hi Charles, thanks for the comment.
Ultimately, your gearing just needs to allow you to hit the highest speed required at the end of the straightaway for the track you are racing on. Any more then this and it's wasted gearing.
So as a general rule the higher gear ratio the stronger the torque?
Hey Dylan. It best to understand it as the larger the gear ratio more torque you will get. 2:1 vs 10:1. Torque is multiplied if the wheels turn once verse the motor turning 10 times. This would be 10 times the torque output at the motor if measured at the wheels.
Going for speed. Whats the difference of a 5/5, 20/20, or a 39/39 pinon to spur. Its all 1/1 but what is the difference? If any
The larger gears will take a bit more energy to spin up and slow down but really this is negligible. There is not much difference and a 1:1 gear ratio is a 1:1 ratio.
What gearing do i need for a 2wd team associated buggy with a 21.5 motor?
You would have to make a calculation using the existing final drive ratio of your vehicle, the Kv of your motor, the cell count you are using, the tire diameter of your buggy and your realistic goal speed.
@3:07 he flipped us off!
I have a 48 teeth spur gear on a 1:8 scale monster truck it's the stock spur gear I just wanna know what size pinion gear I will need bought 2 that don't fit right 17t and a 20t can you help please
What is the pitch of the 48T gear?
it does not say the pitch just says 48t @@RCexplained
Hey, I’m running a Traxxas 4tec, and my setup is 4370kv motor, with a 43 tooth pinion, and a 55 tooth spur. When I pull the throttle, the motor twitches and struggles to pull the spur, is it caused by a lack of torque, or is my motor screwed maybe? Or perhaps is my ratio too close to 1:1?
Hello, here is a video that may help you:
ruclips.net/video/M2k7QloXVNo/видео.html
It sounds like you are experiencing brushless motor (From a sensorless motor) start up hesitation. If so, a brushless sensored motor would make this disappear. If this is not an option follow some of the recommendations in the video link above.
Thanks, I’ll check it out, and heck, I hope my engineering skills can figure it out, if not, I’ll just have to shell out the money for a sensored motor and esc
Isnt it all about power, cause the motor has the most power on a specific rpm, and we want to hit this rpm? Cause if the motor has the same power on every rpm we wouldnt need a gear right?
Gear ratios only allow you to trade torque and RPM to match the required output RPM. The combination of torque and RPM is power. It wouldn't matter how much power is delivered at any RPM if your motor can not hit the RPM range required for your RC application.
What would be the difference if we use same gear ratio but different size of pinions? Like 10/20 and 15/30 teeth pls
Other than size of the gears, nothing.
RCexplained won’t it effect life length of a motor?
@@user-qv5gu5fc8v what do you mean by life length? And why do you think it could be impacted?
RCexplained “life length” suppose to be “lifetime”. (Sorry for bad English). Won’t it have effect on a motor load or heat. Just asking.
One question... If have a 3900kv brushless motor and will be using 60A ESC on my Tamiya TT02RR with stock everything (on 2S) , which pinion gear would you suggest for onroad touring only? Many thanks.
Hi Edwin, it depends on the system that you are after. Hi top speed vs good acceleration.
@@RCexplained Not looking for top speed. Not looking for racing. Just for fun without overheating issues. Just run times .
@@RCexplained It's a new build and I don't know which pinion should I start with. Stock suprs provided in the box are 68T and 64T.
Dese it matter the size of the gears like if the red is medium and blue medium and a small in the middle example
I'm not sure what you mean.
@@RCexplained ok like 0o0