FREE CAR TOOL
Gear Ratio Tuner
Plot theoretical top speeds, map shifting power drops, and adjust custom gear layouts for maximum acceleration.
Top Speed
See what each gear can reach in theory.
Shift Drops
Check where the engine lands after each upshift.
Custom Layouts
Try your own ratios and compare setups.
Try the Gear Ratio Tuner
Enter your gearbox, final drive and tyre details below to see your results.
Enter your own gearing, then test a change side by side. See top speed, acceleration, cruising rpm and shift drops before you spend a penny.
Advanced (optional)
ABOUT THE TOOL
Stop guessing which gear does what
Gearing decides how a car feels. Short gears pull hard off the line but run out of speed early. Tall gears keep the engine calm on the highway, but they can feel lazy when you ask for acceleration. Finding the right balance usually means a lot of maths and a lot of trial and error.
The Gear Ratio Tuner takes the maths off your plate. It lets you plot the theoretical top speed in each gear, see how much engine speed drops after every shift, and try your own gear layouts to chase the strongest possible acceleration.
It is made for drivers, tuners and curious car fans who want to understand their gearing before spending money on parts. Please remember that the results are theoretical estimates. You will find the details in the disclaimer further down this page.
WHAT IT DOES
Three ways to tune smarter
01
Top Speed Plot
See the top speed each gear could reach at a given engine speed, laid out so you can compare gears at a glance.
02
Shift Power Drop Map
Check how far engine speed falls after each upshift, so you can tell whether the next gear lands back where the engine pulls best.
03
Custom Gear Layouts
Change the ratios, try different setups and compare them, aiming for the strongest acceleration for the way you actually drive.
Who is it for?
- Drivers planning a final drive or gearbox change
- Track day, drag and hill-climb fans chasing quicker acceleration
- Tuners comparing different gear setups before buying parts
- Anyone who wants to understand how gearing really works
How to use it
- Enter your gear ratios, final drive and tyre size in the tuner above.
- Set the engine speed you want to work with.
- Check the top speed plot for each gear.
- Look at the shift drop map to see where the engine lands after every upshift.
- Adjust your layout and run it again until the gaps feel right.
GEARING 101
Gear ratios explained in plain words
What is a gear ratio? It tells you how many times the engine turns for every single turn of the wheels. A higher number, such as 4.10, is a shorter gear: more pulling power, less speed. A lower number, such as 2.73, is a taller gear: calmer engine, more speed.
Final drive and tyre size. The gearbox is only part of the story. The final drive (the differential) multiplies every gear again, and the tyre size decides how far the car travels per wheel turn. Change either one and every gear changes with it.
Theoretical top speed. For a given engine speed, the speed in each gear comes from the engine RPM, the gear and final drive ratios, and the tyre size. The tuner works this out for every gear so you can see how far each one can stretch. It is a theoretical figure: it assumes the car has enough power to actually reach that speed.
Shift power drops. When you change up, engine speed falls. If it falls too far, the engine drops out of the range where it pulls hardest and the car loses momentum. Closely spaced gears keep the engine in its sweet spot; wide gaps do the opposite. Mapping the drop for each shift shows you where a layout is strong and where it is weak.
Acceleration or top speed? You usually cannot have the most of both. Shorter gearing helps acceleration, while taller gearing raises the theoretical top speed. Custom layouts let you find the compromise that suits the road, track or strip you actually use.
Real life is messier. Traction, aerodynamics, the power curve, drivetrain losses, weather and road surface all change the final result, so treat the tuner as a planning aid and not a promise.
Disclaimer
The Gear Ratio Tuner is provided for general information and education. Please read the points below before relying on any result.
Theoretical estimates only. Every speed, RPM drop and layout result is calculated from the values you enter. It is a theoretical figure, not a measurement taken from a real car.
Not a replacement for real testing. Actual performance depends on engine power and torque, traction, aerodynamics, tyre condition and growth, drivetrain losses, weather, altitude, road or track surface, vehicle condition and driver skill. Your real results can be higher or lower than the numbers shown.
No guarantee of accuracy. We work to keep the tool useful, but we cannot guarantee that the results are accurate, complete or up to date.
Drive responsibly. A theoretical top speed is not a target. Do not use these results as a reason to drive unsafely or to race on public roads. Any performance driving should only be done at a legal, supervised venue.
Not professional advice. The results are not engineering, mechanical, legal or financial advice. Changing gears or final drive can affect reliability, your warranty, insurance and local road regulations, so please speak to a qualified mechanic or transmission specialist before making changes to your car.
For more information, please also read our site Disclaimer.
Terms of Use for the Gear Ratio Tuner
These terms apply to your use of the Gear Ratio Tuner on Car Care Hubs. By using the tool, you agree to them. If you do not agree, please do not use the tool.
1. Intended use. The tuner is free to use for personal, non-commercial and informational purposes.
2. Accuracy of results. Results are theoretical estimates, as explained in the disclaimer above. You are responsible for deciding how to use them.
3. Your inputs. You are responsible for the accuracy of the values you enter. Incorrect inputs will lead to incorrect results.
4. Acceptable use. Please do not misuse the tool. This includes trying to disrupt or overload it, scraping or copying it without permission, or reselling it or presenting it as your own.
5. Limitation of liability. To the fullest extent permitted by law, Car Care Hubs and its owners are not liable for any loss, damage, injury or expense that results from using the tuner or relying on its results.
6. Changes. We may update, change or remove the tool, and update these terms, at any time. Continuing to use the tool after a change means you accept the updated terms.
7. Privacy. To learn how information is handled on this website, please read our Privacy Policy. Our general Terms & Conditions also apply.
8. Questions. If you have any questions about these terms, please get in touch through our Contact Us page.
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