The Tyre Upsize Ground Clearance Calculator instantly shows how changing your tyre size affects your vehicle’s ground clearance. Select your original and new tyre sizes to find out the exact increase or decrease in the ground clearance (in millimetres). The tool shall also give a clear verdict on whether the change is within safe limits.
This tool uses standard automotive formulas and recommended tolerances (±2% to ±2.5%) so you can confidently upgrade your tyres while keeping your vehicle safe and road-compliant.
Principle Behind the Tyre Upsize Ground Clearance Calculator
Ground clearance is determined by the distance from the ground to the lowest part of your vehicle’s chassis. When you upsize your tyres, only half of the diameter increase lifts the car, since the tyre sits both above and below the wheel centre.
$$ \text{Change in Ground Clearance} = \frac{\text{New Tyre Diameter} – \text{Original Tyre Diameter}}{2} $$Where
$$ \text{Tyre Diameter (mm)} = 2 \times \left(\text{Width} \times \frac{\text{Aspect Ratio}}{100}\right) + (\text{Rim Diameter} \times 25.4) $$Example:
If your original tyre’s diameter is 650 mm and your new tyre’s diameter is 670 mm, your ground clearance increases by (670–650)/2 = 10 mm.
Staying within a diameter change of ±2% to ±2.5% is recommended by tyre manufacturers (Bridgestone, MRF, ETRTO) and keeps your vehicle compliant and safe.
How to Use the Calculator
To use our Ground clearance calculator for tyre upsizing, follow these four steps:
- Select your original tyre size:
Choose the following parameters of your tyre
a) width (mm)
b) aspect ratio (%), and
c) rim diameter (inches). - Select your new (proposed) tyre size:
Enter the values for the new tyre you’re considering. - Click Calculate:
When you click the calculate button, the tool will instantly show your original and new tyre diameters, the change in ground clearance, the percentage change, and a safety verdict. - Interpret the results:
You can interpret the results based on the following. Even if you get the desired ground clearance, make sure that the tyre upsizing is in the safe limits:- Safe: Diameter change ≤2%
- Caution: 2–2.5%
- Not Allowed: More than 2.5%
The results show whether your upgrade is advisable.
Why Ground Clearance Matters
Ground clearance is critical for:
- Avoiding underbody damage on speed bumps, potholes, and rough roads
- Off-road driving or heavy loads
- Maintaining proper suspension geometry
Changing tyre size can improve clearance but may affect stability, fuel economy, and handling. Always use a calculator to check before upgrading.
Frequently Asked Questions
Does tyre size increase ground clearance?
Yes, increasing your tyre size can raise your vehicle’s ground clearance, as a larger tyre diameter lifts the car higher off the ground. The actual increase is half of the total diameter difference between the new and original tyres. However, excessive upsizing can affect stability and is only recommended within safe limits (±2% to ±2.5% of the original size).
How much does ground clearance increase with bigger tyres?
Ground clearance increases by half the difference in tyre diameter. For example, a 20 mm diameter increase raises clearance by 10 mm.
What is the safe limit for changing ground clearance?
Industry standards recommend keeping diameter changes within ±2% to ±2.5% of the original size for safe and legal operation.
Will increasing ground clearance affect handling?
Yes. Higher ground clearance may slightly raise the vehicle’s centre of gravity, which can affect cornering stability.
Can I use this calculator for SUVs and hatchbacks?
Yes, the Tyre Upsize Ground Clearance Calculator works for all vehicles using metric tyre sizes.