Praktische tools voor nauwkeurig werk
Overbrengingsverhouding, Achteras & Toerental Calculator
Vergelijk rijsnelheid en motortoerental over zes versnellingen op basis van bandendiameter en achteroverbrenging (final-drive ratio).
Results assume no tire growth, clutch/converter slip or wheelspin.
How it works
How to use it: enter loaded tire diameter, final drive and each transmission ratio. One input RPM produces road speed in every gear; one road speed produces engine RPM in every gear.
Final drive, axle ratio and gearbox ratio all describe the same number here: the ring-and-pinion (differential) reduction between the driveshaft and the wheels. Catalogs, swap guides and axle-tag references usually list it as a ratio like 3.55:1 or 4.10:1 - enter just the number.
Formula. Wheel RPM = engine RPM / (gear ratio x final drive). Speed = wheel RPM x tire circumference x 60. The reverse calculation rearranges the same relationship.
Example. A 635 mm tire, 1.00 gear and 4.00 final drive travels about 89.8 km/h at 3000 RPM.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Loaded tire diameter
- 635 mm
- Final-drive ratio
- 4.1
- Engine RPM for speed results
- 3000 rpm
- Road speed for RPM results
- 100 km/h
- Gear 1 ratio
- 3.5
- Gear 2 ratio
- 2.1
- Gear 3 ratio
- 1.4
- Gear 4 ratio
- 1
- Gear 5 ratio
- 0.8
- Gear 6 ratio
- 0.67
Primary result: Gear 1 speed @ 3000 rpm: 25.0 km/h.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
This is drivetrain gearing, not a tire-fitment tool. Use measured loaded/rolling diameter where possible. Automatic-converter slip, clutch slip, tire deformation, growth and speedometer calibration can make real readings differ.
Frequently asked questions
Should I enter advertised tire diameter?
A measured loaded or rolling diameter gives a better result because real tires rarely match the nominal figure exactly.
Where do I find my axle or final-drive ratio?
It is usually stamped on an axle tag or door-jamb code, listed in the build sheet, or available from the axle or transmission manufacturer's catalog for your specific part number.
I only need a quick mph-to-rpm check, not all six gears - is there a simpler tool?
Yes - the Speed to RPM Converter solves the same relationship for one gear ratio at a time, which is faster when you already know the single ratio you care about.
Gerelateerde tools
Bandenmaat Calculator
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Wieloffset Calculator
Vergelijk een huidige en nieuwe wiel-/bandenset en zie precies hoe de geometrie verandert.
Snelheid / Toerental Omrekenaar
Zet rijsnelheid om naar motor- of aandrijfastoerental, of toerental naar rijsnelheid, op basis van bandendiameter en één overbrengingsverhouding.
Alternatieve Bandenmaten
Vind standaard bandenmaten, ook met een andere velgdiameter, die binnen een gekozen tolerantie van de totale diameter van je startmaat blijven.