Yes, you can install smaller tires on a car, but it is generally not recommended due to significant safety, performance, and legal drawbacks. The primary issue is that smaller tires have a reduced overall diameter, which directly impacts your vehicle's speedometer and odometer accuracy. They will now read faster and record more miles than you are actually traveling. More critically, smaller tires can lower your car's ground clearance, increase the risk of damaging the wheels or suspension on bumps, and negatively affect handling and braking performance. Modern safety systems like the Anti-lock Braking System (ABS) and Electronic Stability Control (ESC) are calibrated for the factory-specified tire size; using smaller tires can disrupt their function.
While some people consider smaller wheels for a potential cost savings on tires, the risks far outweigh the benefits. The only scenario where it might be acceptable is if you are installing a dedicated set of smaller-diameter wheels with appropriately sized winter tires for seasonal use, and even then, you must ensure the new setup clears the brake calipers and maintains a similar overall diameter. Always consult your owner's manual or a professional mechanic before making such a change.
| Potential Issue with Smaller Tires | Consequence | Typical Impact |
|---|
| Speedometer Reading | Becomes inaccurate, reads faster than actual speed | +3% to +5% error |
| Odometer Reading | Records more distance than actually traveled | Inflates mileage over time |
| Ground Clearance | Reduces height from ground to chassis | Decrease of 0.5 to 1 inch |
| ABS/ESC Performance | Alters wheel speed sensor data | System may engage incorrectly |
| Gearing Effect | Makes final drive ratio "shorter" | Faster acceleration, higher engine RPM at cruise |
| Braking Distance | Reduces contact patch with the road | Increased stopping distance |
| Fuel Economy | Higher engine RPM at highway speeds | Decrease of 1-3 MPG |
