Anyone know about spur gears and how different sizes affect speeds ? I dont know to much about this and wanna change my gears around in my electric buggy. Any info. would be great. Thanks

 

If you reduce the size (read: number of teeth) of the drive gear the car will go slower, but have more available torque (read: acceleration). If you reduce the size of a driven gear the car will go faster, and have less available torque. Two adjacent gears with the same size will have no reduction, they can be referred to as idler gears in this case. The ratio is determined by the number of teeth; e.g. If the drive gear has 10 teeth and it drives a gear with 100 teeth you will see the output speed at 10% of the input speed. Also, torque would increase to 1000% of the input speed. common efficiencies are good at 97-99%...for every mate. The efficiencies are applied to torque multiplication and transfer, NOT speed.

 

Are you running a brushless motor? If so, some of the basic rules don't quite apply. You can often gear the hell out of them and keep gaining top speed AND torque, the thing you have to look out for is heat.

 

yes i am running a brushless 5700kv with a mamba max esc

 

What kind of buggy are you running and why do you want to change your gears around?

If you're just trying to go faster, I'd just step up to a bigger pinion, just make sure you keep an eye on how hot your motor and speed control are getting.

if you still want to go faster but your motor is getting hot (if you don't have a temp gun, just put your finger on it. If you can't hold your finger on it for a few seconds, it's too hot) , it's time to step up to the 6900, or if you're crazy, the 7700.

I could be wrong about this, but I don't think there's much reason to change your spur gear unless you're looking for a very specific final drive ratio for some reason.

 

Well its a team associated b4 buggy , the company that makes the motor and esc control say to use the biggest spur possible with this motor and a 2s or 3s lipo . It should go way over 60 mph with this motor snf the proper gearing , im looking for a high top speed to bash with lol. I was wondering something , i have a temp sensor made by venom that i bought when i had my nitro car's , you wrap a wire around the heat sinks of a nitro motor to tell you the temp. , so i was wondering what if i wrapped that wire around my electric engine on my car , would it serve the same purpose or would temps. be way off . might as well do something with it if i dont have my nitros anymore.

 

To get over 60 with that setup, you'd need a 3s lipo for sure, but then yeah, you could get there.

I don't know about your temp sensor, but you can buy a temp gun that you just point at it for less than $50.

When figuring out your "biggest pinion possible", just make sure the motor and speed control aren't getting too hot, that's the only thing that's stopping you from putting a giant pinion and a tiny spur. If you've already gone to a pinion that's as big as you can fit, step down to a smaller spur, and maybe start with a smaller pinion too, just to be safe, then build back up again, keeping an eye on the temps.

 

Picked up a 87T Spur yesterday and a 17T Pinion , i hope this works , now all i need is a good battery...

 

You've inspired me to move down to a smaller spur gear for my 13.5. The motor barely gets warm right now so I think it's got more to give but a 25t pinion is as big as I can fit, so I bought an 84t spur (replacing an 86t).

Haven't tried it yet but I'll post results.

 

Let me know , im just waiting to get a new lipo and install the parts , maybe by next week . ill post some results also. just picked up a sway bar kit also for the buggy.