A lot of us Marion drivers like our vehicles to reflect our personalities. We're picky about color and body style. We'll customize anything from floor mats to window tints to license plates. One popular way for Iowa motorists to customize a vehicle is to get new wheels.

Wheels come in thousands of designs. Custom wheels can add personality, style or sass to a vehicle. Many of these customizations involve getting a bigger wheel.

Fifteen or 16-inch wheels used to be the factory standard, but today, because a lot of Marion drivers like the look of larger wheels, many vehicles are available with 17 or 18-inch wheels. Optional wheel packages of 20 inches or more are also available in Marion.

If you want to upsize the wheels on your current vehicle, however, you should know it's not a do-it-yourself project. There are factors involved in ensuring your wheel change doesn't jeopardize the safety of your vehicle.

First of all, you need to understand rolling diameter. The rolling diameter is the overall height of a tire. If you increase the rolling diameter of your tires when you upsize your wheels, you may have to modify your suspension to make sure the larger tires fit in the space and don't rub in turns or over bumps. If that's more work than you're willing to do or pay for, then you need to maintain rolling diameter when you change your wheels.

It's not as hard as it sounds. Imagine a doughnut. That doughnut represents rolling diameter, so you can't make the doughnut bigger. However, you can increase the size of the doughnut hole. That gives you a bigger wheel. Tires with reduced sidewall on larger wheels will preserve your rolling diameter.

Rolling diameter is important because your wheels and tires still need to fit inside the wheel well. Also, your speedometer, odometer and anti-lock brakes are all programmed to work with a specific rolling diameter. You'll throw off the readings on your speedometer and odometer if you change your rolling diameter. And for your anti-lock brakes to work properly, your rolling diameter has to be within 3% of factory recommendations. While some Marion drivers who upsize may not be concerned about meter readings, throwing off the brake system is a serious safety hazard.

Further, many vehicles in Marion are now equipped with electronically controlled suspensions. Changing the rolling diameter will negatively affect this system as well, which can lead to a less smooth ride and lower handling performance as well as safety concerns.

Your friendly and knowledgeable Blair's Ferry Automotive tire professional may be able to reprogram your vehicle's computer to adjust for a larger (or smaller) rolling diameter.

So to maintain rolling diameter, you'll need tires with a shorter sidewall. These tires will be designed to give the sidewalls the strength they need to maintain ride quality. Consider that doughnut again. As the wheel (the doughnut hole) gets bigger, the sidewall of the tire (the width of remaining doughnut) gets shorter. That means the tire holds less air. The sidewalls have to be made stiffer to compensate for the decreased air capacity.

To improve their strength, the shorter tires will also be slightly wider than your previous tires. But this means you'll have a larger contact patch, or, in other words, a larger area of tire making contact with the road. This can actually increase your handling performance and decrease braking distances. Many Iowa auto buffs customize their wheels just for this reason—they want the improved performance rather than looks or style. If you drive a truck or an SUV around Marion, you might be interested in the extra control an upsized wheel can provide.

Now, that larger contact patch still has to fit inside your wheel well without rubbing when cornering or when bouncing over bumps or potholes on Marion roads. This is termed fitment, and you may need a few adjustments so your new wheels will fit properly. You may need spacers so that your brakes will fit inside the new wheels, as well.

Blair's Ferry Automotive tire professionals are experts at mounting, adjusting and customizing wheels. They can give you a lot of good auto advice about wheels and tires and how they affect driving performance and car care. They can help you select wheels and tires that will suit your driving needs and habits.

For example, if you drive off-road around Marion, you should consider a higher profile tire. This type of tire will protect your rims from damage while you're bouncing over rocks. Or, if you tow a trailer or haul heavy loads around Iowa, you'll want a tire with a load rating equal to your demands. Your friendly and knowledgeable Blair's Ferry Automotive tire professional can help you with these types of concerns.

Once you've got your new wheels, have your service advisor at Blair's Ferry Automotive see if you need an alignment. You don't want those new wheels and your higher performance compromised by poor alignment. Get the most out of your investment by getting the work done right at Blair's Ferry Automotive in Marion.

Last but not least, remember tire pressure. With larger wheels, your new tires will hold less air and they'll need slightly higher pressure. You'll need to stay on top of preventive maintenance and keep them properly inflated. Be sure to check their pressure at least once a week. If you don't keep your tires at their correct pressure, they will wear out really fast. It will also affect your braking and handling performance.

So smile and show off your vehicle around Iowa. Make it all yours. Bumper stickers, vanity license plates, custom wheels — strut your stuff!

Blair's Ferry Automotive
1565 Blairs Ferry Rd
Marion, Iowa 52302
319-447-6310
http://www.blairsferryautomotive.com

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