RC Electric Off-Road Trucks, Buggies, Truggies and more Discuss electric RC off-road, buggies & trucks here. Also discuss brushless motors, speed controllers aka ESC's, brushed motors, etc

Gear for motor and battery question

Old 05-21-2020, 10:56 AM
Junior Member
Thread Starter
Join Date: Dec 2019
Posts: 16
Likes: 0
Received 0 Likes on 0 Posts
Default Gear for motor and battery question


My son has a car he has been building and we are at the point where we noticed the motor did not come with a gear for the end of the motor. What type of gear do we need? The car he has is the following: PR S1 V3 FM SPORT 2wd Buggy kit

Here is the motor:
Hobbywing XR10 Justock Sensored Brushless ESC/SD G2.1 Motor Combo (17.5T)

Also, we noticed that the Engine controller does not have ends to go into the lipo battery it is just bare wires. I would guess I need to crimp or solder something on here?
HobbyStar 3700mAh 7.4V, 2S 100C Hardcase "Shorty-Lite" LiPo Battery

Thanks for the help
Old 05-21-2020, 05:02 PM
Join Date: Jan 2016
Posts: 368
Likes: 0
Received 15 Likes on 14 Posts

Yes , you will need to solder on a plug .
The one I googled had a " Deans " connector / plug on the battery . ( red T shape ) .
The battery will be the female side so the tabs are not exposed and able to short out .
The website for the car showed the pinions but a quick look at the manual didnt show anything .
It showed them as 48P .
This is the gear Pitch ( the size of the teeth ) .
Motor shaft should be 3.17mm ( 1/8" ) .
These are a common size , and available online or at your local hobby shop .
81 tooth spur gear , if I read the manual right , so some where about 20 Teeth would be a starting point . You can get gears individually or sets ( eg 5 gears from 17T - 21T ) .
If Bill jumps on , listen to him ! He is a very technical racer and will help with your setup .
Old 05-21-2020, 05:27 PM
bill_delong's Avatar
Join Date: Mar 2009
Location: Austin, TX
Posts: 740
Received 51 Likes on 45 Posts

The user manual for the motor you bought provides you with the recommended gearing here:

The manual for your buggy provides the information for the drive ratio on pages 11-13:

Gear Diff = 55T
Top Shaft = 20T
IDR = 55/20 = 2.75

Spur = 81T
Pinion = x

FDR = 2.75 x (81/x) = 6.0 = recommendation by HobbyWing

x = (81 x 2.75) / 6 = 37T pinion

Only problem is that you can't fit a 37T pinion so you'll need a smaller spur to get proper stock gearing, I don't run 2WD so I don't know for sure, but I would probably go with a 73T spur so the math would go like this:

x = (73 x 2.75) / 6 = 33T pinion which should fit

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.