Like every other cars, AWD vehicles also goes through the wear and tear process. Certain components need a regular inspection, while specific requirements must be changed after a certain time/ mileage as per the owner’s manual.
Tires are the most important piece that should be inspected regularly, maintained, and replaced as per the protocol. Regardless of what vehicle you drive, new or old, proper tire pressure as per owner manual, wheel alignment, and wheel balancing are main maintenance required. This is important for vehicle dynamics and handling and is needed to achieve the tires’ design life. Besides this, there is one more critical maintenance step: “TIRE ROTATION” after a specific interval.
This gives the tires uniform wear.
Tire Rotation and AWD Vehicles:
Although tire rotation might not sound significant in your regular front wheel or rear wheel vehicle, it is imperative to drive an AWD vehicle like Sportage and Tucson. The AWD in these vehicles and many others on the market have a sophisticated system that keeps monitoring the road condition. The AWD system has viscous clutches and / differential coupling, resulting in every wheel rotating with different speed.
There are sensors on each wheel, which are continuously monitoring the rotation of the tire. The data is sent to a computer control module, which in return, transfers a certain percentage of the torque if required with the help of a computer-controlled transfer case. The system automatically divides the power between the wheel and basically cuts power from the wheel, spinning faster than the rest and transferring it to the wheels that are moving slowly or stopped or stuck.
In brief, there is a computer-controlled transfer case that provides traction and stability control to wheels, and all this is based on the data the system collects from the tire’s behavior with the road surface.
Mismatched Wear on AWD Vehicles:
As tires wear over time, the thread depth reduces and reduces the overall diameter of the tire and reduces rolling circumference. In the case of AWD vehicle, all tires MUST wear within a certain degree and limit. As the tire wears, the number of rotation required to cover a particular distance increase. In case of mismatch, the tire might be forced to make up the required distance or stop.
If there is mismatched wear, the AWD module will get improper data as different rotational speeds of tires will simulate tires slipping. The AWD system will go in unnecessary stress and wear, especially if you drive on straight highway road. In other words, the system will detect a non-uniform rotation and will send or cut power to a particular wheel, although in reality, the road condition might not be needing that. Also, keep in mind the AWD/ ALL WHEEL DRIVE as in Sportage/ Tucson are still technically front-wheel drive vehicles with front wheels as main driving wheels. The rear wheels only come in action when the system detects the need for it.
Front wheels on Sportage / Tucson, like any other front-wheel-drive vehicle, will wear faster. The AWD system is sophisticated and capable of handling the different wear patterns but only to and within a certain degree and specific limit. As an example, Subaru allows a maximum of 7mm of variation in the circumference of tire. Please consult your owner manual.
Is It a Problem?
Regularly check tire pressure, which one should do even on FWD vehicles. Wheel alignment and balance should be periodically inspected and as per the owner manual.
AWD vehicles must do the tire rotation every 7500-10,000 kilometers or whatever the manufacture recommends.
The front tires wear much faster than the rear tires on a front-wheel-drive vehicle, so all tires must have uniform wear, which can be achieved via a proper tire rotation.
Tire rotation must follow the industry-standard rotation pattern, and it depends on the type of tires you have on your vehicle. Directional, Symmetrical, Asymmetrical tread patterns have different tire rotation pattern. I am intentionally not sharing the patterns because many people would get confused, and most might not even know what type of tire they have.
Tire Wear and Precautions in AWD Vehicles:
If one tire got damaged, you must replace all the four tires with the same brand and replace it with the exact same size and specifications as recommended by the manufacturer. The AWD system is calibrated for the specific tire size as given by the car manufacturer.
This is one of the main reason the AWD Sportage comes with the full-size alloy wheel as spare. Technically, it is always a best practice that the spare wheel also becomes a part of the tire rotation pattern. If the spare wheel is not part of the tire rotation schedule, then the spare wheel should be treated as a spare wheel only and temporary substitute.
This means, if the actual tire is flat/ punctured, it should be fixed as soon as possible, and the spare tire should go back to the trunk. The spare is full-size alloy and many people will think it is the same, so they can keep on using it and store the punctured tire, which is fixed in the trunk.
This will result in a newer tire [ Spare Tire ] on the vehicle concerning the rest of the three. This can cause trouble for the AWD system. So, either the spare tire should be part of the rotation pattern OR else, use the spare tire when needed, fix the flat tire and immediately put the spare wheel back in the trunk.
If you have one tire damage, you can replace it with the exact same brand, and with the exact same tread pattern instead of replacing all 4 tires, provided you have the tire shaving service available from the tire selling store. Basically, the new tire is shaved using a particular machine to bring the tread depth down to the same level as the rest of the vehicle’s tires. I am not sure if such an option is available locally but should be kept in mind.
Lastly, improper tire maintenance and mismatch tires damage the AWD system and are not covered under warranty.
Visit PakWheels Auto Store to buy products regarding car wheels maintenance.