Published on February 22nd, 2017 | by Danielle Williams

Ask CATS #10: Answering Your Car FAQs.

Our Consumer and Technical Services (CATS) team receives questions about car care, buying a new or used vehicle, auto repairs, vehicle inspection, driving costs and more. If you have a question for CATS, call 1-866-464-6448 or

We understand not everyone is a car pro, so that’s why we’re here to help and give you information and tips for your car. These are real questions from car owners who want the inside scoop. Here are answers to some of your questions.

Question #1: I have two tires with different mileage on each. Should the newer tires go on the front or the back?

There are two perspectives on this. The first is to have the best tires on the rear. The front tires on a front wheel drive vehicle already get very good traction due to the front wheels bearing the weight of the engine and transaxle. The rears get much less traction due to the relatively low weight at the rear of the vehicle. The best tires on the rear (providing the tires on the front are at acceptable tread depth levels) help compensate for the loss of traction due to the reduced weight.

The second is to have the best tires on the front. The reason is that worn tires are more susceptible to blowouts and are more likely to lose traction in sudden maneuvers, like being cut off by another driver. So we recommend the best tires on the front.

Question #2: Would CAA recommend nitrogen or air in tires?

We recommend nitrogen-filled tires. Having nitrogen in your tires can prevent premature tire leakage. Nitrogen tires are not affected by temperature, therefore keeping your tires at a proper level for a longer time.

If you have nitrogen-filled tires and you encounter a tire deflation issue on the road where no nitrogen is available, topping up the tire with air will not result in any ill effects to the tire or your vehicle’s handling.

If you currently have air-filled tires and want to change to nitrogen tires, it will cost about $49.99 and likely take about 30 to 45 minutes to complete as the facility must remove all of the air first.

Question #3: What’s the difference between Krown and “undercoating” products?

Undercoating is an old technology designed to cover the exposed surfaces of your vehicle with a wax or tar based coating. While these undercoating products look good at a glance, they’re not truly effective in protecting your vehicle. Undercoating products don’t have the ability to creep and penetrate in the seams, spot welds and other hard to access areas of your vehicle like Krown will. These are the areas the rust is most likely to form! Also, as these coatings wear, crack and become damaged, they can actually trap moisture against the metal surfaces of your vehicle and accelerate corrosion. Many people classify Krown as an undercoating or rust proofing product, but Krown’s unique formulation is able to protect your vehicle in ways that traditional undercoating cannot.

Question #4: What is Carnet de Passages?

Basically you can think of it as a passport for your car. It’s an international customs and temporary export-import document used to clear customs without paying duties and import taxes on merchandise that will be re-exported within 12 months. It offers a promise/guarantee to a foreign government that the vehicle identified in the Carnet, if granted temporary importation status for tourism purposes, will be removed from the country within the time limit imposed by the respective jurisdiction. A Carnet is valid for one year from date of issue.

Boomerang Carnets is the new service provider of Carnet de Passages for AAA, CAA and non-members in both the U.S. and Canada. Here’s their information:

Carnet Help Line: 1-800-282-2900
Mobile Carnet Help Line: 1-847-638-8325
Fax: 1-847-381-3857

Question #5: Who does CAA recommend for rust proofing?

We recommend Krown Rust Control. With annual applications of Krown, you will be reducing the cost of maintenance, increasing resale value and extending the life of your vehicle.

Krown is a petroleum based rust preventative. It is a non-evaporating liquid product that creeps over metal surfaces and provides a protective barrier on the surface. Krown’s unique formulation is absorbed into existing corrosion and pushes out any moisture, thus slowing down any further corrosion significantly.

Krown Rust Control will not void any manufacturer’s warranty, unless the manufacturer’s warranty expressly states that the third party rust control products will void the warranty. If concerned, address the question directly to the manufacturer as opposed to the dealership. Click here for more information.

Next month make sure to check out our new Ask CATS video serieswhere we sit with the car pros and get the answers to all your automotive questions.

Got a question for CATS? Call us at 1-866-464-6448 or email us

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