Get our free gear calculator app, so it's always handy! Or check out our other free apps:
- Gear Recommender App
- Speed Calculator App
- RC Speed Run

So Dialed RC Setup App on the App StoreSo Dialed RC Setup App on the App Store

5 Stars on the App Store

Travis C.
This app is awesome! It has all the main RC cars already in it. You don't have to go look up diff ratios, it's already in there per your car! Best free app I've ever downloaded. It led me to download their other apps.
Joseph O.
Great to have a quick calculator on hand when at the track. Nice to have a compare feature to see current and new gear change calculation.
Chris W.
Helps me go fast.
Zaulu B.
Good app - it really lets you see what you are doing when pairing your gears. I would recommend it for anybody trying to hit high speed.
Cody B.
Helped me get a perfect top out speed and keep good temps.
Mark F.
Must-have.
Clay B
AWESOME APP FOR RC NO PREP OUTLAW! GOD BLESS ✝️
Jeremy F.
A must-have for RC racing.
Dale S.
I like the rollout and the red and green percent  change as it relates to rpm and motor temps.
William W.
This app is a big help to me to actually know and see what my drag car is doing. Very useful app, highly recommend it to anyone who drag races.
Ian C.
Something every racer should have
Frank G.
It's nice to see which values ​​you set on the car without calculating, and the changes are displayed directly, including explanations of how the settings affect you.
Travis W.
Fast, simple, free and accurate.
Alan L.
Easy to use and covers a wide range of models
John M.
Great app! Especially helpful to have " current" and "new" displayed side by side!
B. C.
Very effective app & easy to use. The side-by-side comparison of current & desired gearing is the best part. Also, I'd like to Thank you guys/girls @ RC Gear Calculator Pro. You've helped me a lot with gearing my ARRMA LIMITLESS ⅐ scale speedrun car. Saved me a substantial amount of time using this app.
Louis M.
Very easy and intuitive to use. It has been really helpful pairing different spur and pinion gears. No guessing or calculations needed. 0% or 10% change, or whatever, it shows you.
Cole M.
Great little tool, get their other app too, called "SO DIALED." It's a lifesaver for tuning!
Jonathan H.
Excellent tool to manage your desired FDR. I use it on my touring car and my 1/12 pan car.
Kris D.
Great info fast. Makes changing gears very quick
Heath M.
It has changed me as a human, made me care a little more about humanity and the fellow creatures on this Earth. It's also a great R/C gear calculator.
Michael D.
Life saver...awesome app that helps tremendously.
Dane K.
Works great - easy way to figure out final rollout.
Bryan T.
Excellent app for all tuning needs
Jason R.
Easy to use, and convenient!
Benjamin C.
Perfect.
Billy J
This app is so helpful. It's a great tool to get your RC where you would like it to be.

Online Gear Ratio Calculator

Looking for a quick gear calculation, so you don't have to download an app? Try our gear ratio and rollout calculator to find the right pinion and spur for your car, whether it's Team Associated, Tamiya, Traxxas, or any other make. Enter your car's internal drive ratio to see the final drive ratio (FDR), and see the percentage change in gearing you'll get from a new pinion and spur.

Gears & Ratios

Enter your gearing to see the how your ratio will change.
Ratio
1
1
Ratio change
0%
Internal ratio
(Optional)
FDR
1
1
Rear tire diameter (Optional, for rollout)
Rollout
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Get our free Gear Calculator App (links above),
or try our
Gear Recommender App!

Looking to calculate the top speed of your car? 
Try our
RC Speed Calculator App!

Change Impact Chart

Click/tap the gears to see how new gears will affect your ratio:
Pinion
Spur
13
0%
74
0%
14
0%
75
0%
15
0%
76
0%
16
0%
77
0%
17
0%
78
0%
18
0%
79
0%
19
0%
80
0%
20
0%
81
0%
21
0%
82
0%

Negative changes indicate a steeper ratio: higher top speed, but more strain on the motor/engine. Positive changes give more acceleration and put less strain on the motor/engine.