18 - Will Shaving Your Road Course Tires Actually Make Them Last Longer?
Yes, this is true and something I addressed in a recent "Contact Patch" column. To recap: One of the reasons radial racing slicks are so effective is because they feature shallow tread depths and their contact patch acts as a single unit-they don't have normal tread blocks. Basically, any tread design breaks the contact patch down into smaller elements, and additional deep tread depth (required to enhance wet traction) allows tread-block squirm, which will reduce dry performance.
Again, the folks at Tire Rack explain that shaving a tire is an effective means of permitting more of a tire's performance capability to be realized earlier in its life. A shaved tire's tread profile will usually result in a slight increase in the width of the tire's contact patch, putting a little more rubber on the road. The resulting shallower tread depths reduce the tire's slip angle, increases its responsiveness, and helps stabilize its cornering power by minimizing tread-block squirm. Minimizing tread-block squirm also reduces heat buildup and the risk of overheating its tread compound. In many cases, shaved tires used in competition or at driving schools may actually have a longer useful life than tires that begin being run at full-tread depth.
19 - What Are Tire Speed Ratings And Where Can I Find Them?
A tire's speed rating is expressed as an alpha-numeric symbol you'll find on your tire's sidewall that tells you the maximum sustained speed the tire is capable of safely handling. An H-rated tire, for example, is built to be safe for continuous operation at speeds up to 130 mph. Most current model year family-type cars have S (112 mph) or T (118 mph) speed ratings. High performance cars often have tires with a V (149 mph) or ZR (in excess of 149 mph) speed rating. A few ultra-performance cars have W (168 mph) and even Y (186 mph) speed-rated tires.
You will find this speed rating expressed one of two ways. One, as part of the tire sizing information, such as 275/40-ZR17, a ZR rated tire. Or, you may also find it expressed as a numeric-alpha "Service Description" such as 92 V, typically printed on the tire's sidewall behind the size info. This is a combination of load rating (92) and speed rating (V).
 This terminator Cobra is really...  This terminator Cobra is really working the tires hard-notice that even the inside rear tire is picking up the outside edge. In the second photo, notice how the weight transfer onto the left rear tire is affecting the contact patch of that tire. |  Properly set-up Fox Mustangs...  Properly set-up Fox Mustangs can also load up their tires. Check out the sidewall deflection in the driver front, with the passenger front is leaning away from the turn, essentially lifting the tread of the tire off the surface of the track. |  Sliding the car through the...  Sliding the car through the corners is a sure-fire way to accelerate tire wear. |