Can Using Incorrect Tire Sizes Damage Your Car?
When it comes to tires, ensuring the correct size for each axle is crucial, but what about mixing sizes on the same vehicle? For instance, in high-end vehicles like Mercedes and BMW, rear tires are often wider than the front. Manufacturers intentionally design these for specific reasons, such as improved handling and performance. Nevertheless, it's essential to maintain the original sizes provided by the manufacturer to achieve optimal performance.
Why Consistency in Tire Size Matters
Switching tire sizes can disrupt various critical vehicle functions. For example, traction control and ABS systems rely on all wheels turning at the same speed. Incorrect tire sizes can disable these systems, leading to unsafe conditions on the road. In all-wheel drive cars or trucks, mixing tire sizes can cause extra stress on differentials, potentially causing significant damage to your drive train.
Consequences of Mixing Tire Sizes
The risks of mismatched tire sizes vary depending on the degree of deviation. In some cases, the damage might be negligible. However, in other instances, issues can range from minor to severe. For example, changing tire sizes might cause the speedometer to read inaccurately. In extreme cases, such as switching to much larger tires on trucks, the speedometer may be off by a significant margin—potentially reading just 65 mph when the vehicle is actually traveling at 80 mph.
Such inaccuracies can lead to speed-related issues. For a driver, constant mental math to recalibrate their perception of speed can become a distraction and detract from the overall enjoyment of the ride. This is particularly true for high-performance motorcycles where the speedometer reading can vary by as much as 10 to 12 mph. To rectify this, a speedometer correction device may be necessary. I personally had to install such a device on my motorcycle to ensure my GPS and speedometer readings were in sync.
Correcting Speedometer Inaccuracies
Speedometers calibrated for metric speeds might read incorrectly in imperial units, which is common on imported motorcycles. The manufacturers often intentionally set these to be slightly higher to avoid penalties from the American government for underreporting speeds. In my case, my motorcycle's speedometer read 72 mph when the GPS showed 65 mph. This difference was due to the speedometer being calibrated to read 12 mph higher.
To correct this, I installed a small electronic gizmo under the seat that allowed me to adjust the speedometer reading. After some trial and error, I was able to get the speedometer to read within 1 mph of the actual speed at various speeds. This small tweak made my riding experience more enjoyable and accurate, allowing me to focus on the ride rather than constantly correcting my mental calculations.
When it comes to using the correct tire size, it is vital to consult the manufacturer's specifications. Installing tires of different sizes can lead to a range of issues from speedometer inaccuracy to drive train damage. Therefore, it's important to adhere to the manufacturer's tire size recommendations for the best driving experience and safety.