Take the Vehicle Manufacturer's Recommendation
We mentioned earlier that vehicle manufacturers often have a recommended tire size and type for each vehicle. This recommendation is based on the size, weight, load capacity, off-road capability and steering for your specific vehicle. Changing the tire size and type could impact the handling of your vehicle. We talked about how plus sizing a tire can change certain aspects of your driving experience.
Changing the tire size can also affect your speedometer reading. For many cars, the speedometer reading is based on one full revolution of the tire on your vehicle. If the tire size is changed, then the time it takes a tire to make one full revolution will increase [source: Yahoo Autos]. Since the speedometer rating is calibrated for only one length of rotation, a newer tire that is larger will inhibit the speedometer from reading the correct speed of the vehicle.
If you have an electronic automatic transmission, changing your tire size can also impact the timing of your shifts [source: Yahoo Autos]. This may impact your fuel mileage, uphill and downhill transmission changes as well as the general shift timing.
Downsizing your vehicle's tires can also have negative effects as well. It's obvious that the tires on your vehicle are keeping it up off of the ground. Well, the size of those tires is part of the reason why the car doesn't come crashing down. If you tried to put a smaller size tire on your vehicle, you would be adding additional stress to the tire that it may not be able to handle. A smaller sized tire may need a different wheel rim to handle the changes.
You can change the size of the tires on your vehicle but these problems must be factored in and adjustments made so that the vehicle will function correctly with the new tires. Changing the tire diameter or the aspect ratio is possible if you can maintain the correct load capacity and adjust other potential problems, like the speedometer [source: Yahoo Autos].
Up next, find out what you should ask your mechanic to check when you buy a new set of tires.