Pinion And Spur Gearing Guide

[Addict Rc]

So I’ve seen quite a few post recently on how to find the right gearing for a RC car. So here ya go.

*As a reference use the stock gearing of your RC as a “mid point”*

If you’re trying to go slower. You’ll want to add a bigger spur gear and smaller pinion gear. What that does is it makes the input (motor) speed reduced and with the bigger spur gear it makes it slower to turn a full rotation. Also may I add. This will deliver more torque and less speed.

If you want a faster RC car. You’ll need to add a smaller spur gear and a bigger pinion. Which now the input (motor) is bigger than the output (spur gear) it makes the output (spur gear) move faster which makes your RC go faster. Also may I add. This will deliver less torque and more speed.

HOW DO I FIND THE RIGHT GEARING FOR MY RC?
Finding the right gearing for your RC car is crucial. Because if you put too big of a pinion and too small of a spur gear. You can overheat, wear drive terrain down significantly, smoke your esc ETC. but if your under-geared you may have too much torque and not enough speed at all.

I personally would…
1. What type of RC are you trying to gear
2. Are you trying to go slow or fast
3. Get ~4 different spur gears
4. Get a little pack of a wide variety of pinions.

Make sure electronics aren’t overheating or cutting out. If that is an issue. Gear down.

Gearing can be frustrating. I would also recommend running each type of gearing to find what works best for your RC. Make sure to follow this guide when you’re new to gearing. Good luck!

 

[WickedFog]

If you want a faster RC car. You’ll need to add a bigger spur gear and a smaller pinion.

Oops - backwards

Also, it's not always necessary to change both gears. You might need to change the spur to get bigger pinions to work, as your motor adjustment slot will only allow for certain combinations of pinions/spurs. It just depends on how far from stock gearing ratios you need to run.

 

[bill_delong]

Here's my take:

• What gearing for upgraded electronics?

A temp gun is probably the single most important tool in helping you protect your investment. Let the temps tell you how to gear your car with the following general limits for most electronics on the market:

Battery < 120°F
ESC < 140°F
Motor < 160°F

***Be sure to check the manual for your electronics to see what their specific temp limits are, if none are listed then use the suggested limits listed above.

Anytime you change your battery cell counts or capacity (i.e. from 2S to 3S, or NiMh to LiPo) then you will likely need to re-gear appropriately as well, especially if you increased run time, temps will grow exponentially for sustained duration.

Here are a couple temp guns to consider:
http://www.banggood.com/GM320-Non-Co...166379201304IO
http://www.harborfreight.com/non-con...ter-93983.html

hot battery = replace with higher C rated pack
hot motor + cool ESC = under geared
hot ESC + cool motor = over geared
hot everything = WAY over geared

Start with your stock gearing and then go from there... also keep in mind that driving surface conditions, tires, worn bearings etc all effect your temps... always check your temps just like a 1:1 car has a temp gauge to tell you the overall health of your system.

Remember, a temp gun is the single most important tool to own in this hobby. If you have the money to upgrade your electronics, then you should also include the cost for a temp gun without a doubt

*** For stock racing, here are some tips for using a motor analyzer to get max potential out of a motor

 

[Addict Rc]

Oops - backwards

Also, it's not always necessary to change both gears. You might need to change the spur to get bigger pinions to work, as your motor adjustment slot will only allow for certain combinations of pinions/spurs. It just depends on how far from stock gearing ratios you need to run.

Fixed. And yes, you don’t need to change em up. But I was just making examples.

 

[Aitch]

Hey up folks, a question for those in the know, the stock gearing on my strada is 48 spur x 15t pinion, i have ordered a metal gear set as the spur is getting hammered with my driving, but that's another matter altogether, so out of the following pinions and with the much larger spur 64t being the only size spur in metal i could find online, anyway the pinions choice is 15t,17t,21t, 26t and 29t, so which will make my car lots faster on the top speed, i have no issues with temps on motor as i'm running twin heatsink fans too, thanks in advance and check out my usual rc carnage on my youtube channel.

Aitch