NVDAILY.COM | Lifestyle/Valley Scene

Posted February 21, 2013 | comments Leave a comment

Ask Dave the Car Guy: Tires, compounds and tread design

dave-herman.jpg
Dave Herman

By Dave Herman

When my students ask me for ways to increase car performance, I ask them, "What is performance? How far can the car travel in 3 seconds? How does it handle an off-camber turn? What is the braking or stopping distance? Horsepower? Safety?"

The first four are met with smiles and positive body language, but safety, well immediately the smile is replaced with that blank teenage stare of "whatever."

Safety in this case is the ability of the car to get from point A to point B reliably. What if your tires are so worn you can't make it up a snowy hill or hydroplane into another car in the rain? That high-dollar stereo system won't sound so sweet as you lose control, lose you car, and possibly your health.

You have to make smart choices. Skip the stereo for now and go for the new tires. You need to ensure that you, others on the road, and your car are safe. After all, no car, no transportation, no job, no money, no school, no date, no fun.

So, let's use the rest of this column space to discuss types of tires, compounds and tread design.

You don't need the most expensive tires to get you to and from your obligations. You do need to know the difference between street tires, all weather, and mud and snow tires.

Before I get into all the technical stuff, let me remind all drivers to check your tires often and especially when there are major temperature changes as it can affect your tire pressure substantially.

Street tires have different tread designs. Some are better suited for dry pavement, some are designed for dry and wet traction, some are designed more toward wet traction with tread design to channel water from under the tire to decrease hydroplaning in heavy rain and standing water.

Hydroplaning is when you have a film of water between the road surface and your tire contact area, causing a total loss of traction. You may notice if you watch auto racing that they run tires that have little or no tread on the tire contact surface. The tires work great on a clean dry paved track as they have more surface area contact than a treaded tire. But, as soon as it looks like rain, what does the pit crew do? They "pit" and get the treaded rain tires on before the driver hydroplanes and loses control of the car.

Mud and snow tires with deep aggressive tread are designed to self clean the mud and snow from the tread. This helps traction in deep snow. Some snow tires have a soft compound that stays soft in extreme cold and even helps with traction on ice. You should remove them as soon as snow season is over due to the fact the soft rubber compound wears out quickly on dry pavement. Also snow tires and aggressive treads can be very noisy on dry pavement.

Not to over simplify, because there are books devoted to the science of tires and our space is limited: tire compounds are important.

Race tires have a tread wear rating of 0 to 60. They are sticky and pick up everything from cigarette butts to gravel. Street tires generally go from a tread wear rating of say 200 soft compound with a 20,000-mille guarantee, to a tread wear rating of 600 hard compound with say a 60,000-mile guarantee.

Yes, the 60,000 will last longer, but can be a harder rubber compound. If I am a spirited driver and tend to drive hard in the rain, this tire could be deadly for me or my loved ones. I will pick a softer tire with a proper tread pattern and choose to give up some longevity for safety.

Tires also have speed ratings and load ratings. Speed ratings help you select a tire designed for the speeds you will be driving on the street or for particular driving events. Load ratings are important, also, as they help you put the proper tire on you car or truck that will be safe for the load you will be hauling, with less chance of tire failure.

You will find more information online with charts to help you select the proper tire for your needs. Learn about tire selection before you talk to a tire professional so that you will be able to understand them and come to a conclusion as to their knowledge and advice. Remember to analyze price versus performance and always remember the tire is what connects you to the road. Be safe!

Before his retirement, Dave Herman ran one of the largest independent German service centers in Northern Virginia. He has built, raced and taught racing to Porsche/BMW drivers. He lives in Shenandoah County, where he has opened a driving school. Email your comments and questions about anything automotive to info@nvdaily.com. Read more of his columns at nvdaily.com/lifestyle/guest-columns


Copyright © The Northern Virginia Daily | nvdaily.com | 152 N. Holliday St., Strasburg, Va. 22657 | (800) 296-5137