It's probably a safe bet that-even for a tire retailer-the letters UTQG don't exactly roll off the tongue. Sure, most tire professionals are probably aware that UTQG is alphabet-soup shorthand for the federal government's 28-year-old Uniform Tire Quality Grading standards for treadwear, traction and temperature resistance.
But it's likely that a dealer's hands-on experience with UTQG is limited to peeling those federally mandated information labels off a customer's new tires.
When Tire Business decided to look at how tires make the UTQG grade, the folks at Standards Testing Laboratories (STL) Inc., one of the country's leading independent tire testing organizations, came to the rescue.
UTQG testing is just one of the services that Massillon, Ohio-based STL conducts around the clock, 365 days of the year for tire, wheel and auto companies. Its UTQG temperature testing is performed in Massillon, while the treadwear and traction tests are done in San Angelo, Texas, where Tire Business was able to watch some tests in action.
Where, when and how to perform the tests are meticulously spelled out in the Code of Federal Regulations' Section 575.104.
``We hit deer. We've hit cows. About a year or two ago, a horse ran into the road. It totaled the truck-a Chevrolet C1500-and the horse died. It came up over the hood and right into the windshield.''
Lynda Underwood is going over some of the hazards of UTQG testing. Stray animals, she noted, are particularly a problem during a full moon. But the day shift can be just as perilous. ``We also try to avoid running over rocks and dead animals,'' she adds, noting that that includes rattlesnakes. The fangs not only could puncture a tire-any retained venom poses a threat to the tire repairer.
Ms. Underwood, who has been testing tires for 25 years (the last 11 with STL), pointed out that she hasn't seen anyone suffer serious injuries. STL's facility in San Angelo is practically across the street from the Department of Transportation's Uniform Tire Quality Grading Test Center at Goodfellow Air Force Base.
When tires are shipped to STL for testing, they are mounted on identical rims, inflated to the applicable pressure and mounted on a vehicle, often STL's workhorse Toyota Tacoma pickup trucks. When a manufacturer wants the tires tested on a particular vehicle, STL either rents, leases or buys it.
A set of reference tires-called course-monitoring tires-gets the same treatment. The tires run $262 each, while the cost of a typical four-vehicle UTQG testing convoy runs about $12,600, said Douglas M. Garven, STL's vice president of marketing.
UTQG testing is done with either a two- or four-car convoy, with one vehicle always equipped with the reference tires. Each vehicle is loaded to 85 percent of the specified test load, and the wheels are aligned to factory specifications.
The convoy makes two ``break-in'' runs of the 400-mile circuit designated by the regulations. After this 800-mile break-in is completed, all the tires' tread depth is measured to the nearest thousandth of an inch at six equally spaced points in each tread groove.
The wheel alignment is adjusted once more, and the convoy is run for 6,400 more miles. Tires are rotated and inspected after each 400-mile shift. Each vehicle's position in the convoy also is rotated. Two shifts a day are out on the West Texas test loop, which is designed to simulate the road surfaces and driving done by the public.
Treadwear testing normally is completed in nine days. At the end of the required 7,200 miles, the ``candidate'' tire's rate of wear is compared with that of the course-monitoring tire.
The regulation states that ``the treadwear grade is a comparative rating based on the wear rate of the tire when tested on the government's test course. For example, a tire graded 150 would wear one and one-half times as well on the government course as a tire graded 100.''
The government points out that treadwear in the real world ``may depart significantly from the norm'' due to different driving habits, road characteristics, climate and vehicle usage. Tire manufacturers sometimes use lower treadwear grades to be conservative or prevent marketing conflicts.
Ms. Underwood, who is the day-shift trainer in San Angelo, said the job requires common sense and maturity. ``We drive the posted speed limit,'' she said. ``If it says 60 mph, we do 60. We've been called road roaches by people getting irate with us. We try to pull to the shoulder and let traffic go around us. We try to avoid any type of trouble on the highway.
``We're shooting for consistency. If we make turns too fast it will wear the corner instead of the tread and that messes up the testing.''
The traction phase of the UTQG testing measures a tire's resistance to wet-surface skidding. The tests are conducted on multi-lane asphalt and concrete test pads installed in a former runway and taxiway at Goodfellow Air Force Base. Naturally, the inflation pressure of the tested tire, as well as that of a standard wet traction reference tire, are set to the required specifications.
Bob Gregg, a safety compliance specialist for the Department of Transportation's UTQG Center, makes the task look easy. It's not. The trick is to hit the first test pad at exactly 40 miles per hour, maintain that speed, lock one trailer wheel and record the locked-wheel traction coefficient. Then it's on to the other test surface, where the same test is applied.
This is repeated until 20 measurements on each surface have been recorded. Software helps make the process more efficient. The results are averaged and computed using specific formulas to arrive at the adjusted traction coefficient-the higher the coefficient grade number the better. ``It's fascinating, interesting work,'' Mr. Gregg said.
To earn the best rating (AA), the tire's adjusted coefficient must exceed 0.54 on asphalt and 0.38 on concrete. An ``A'' grade requires more than 0.47 on asphalt and more than 0.35 on concrete. The ``B'' traction grade takes more than 0.38 on asphalt and more than 0.26 on concrete.
Finally, a ``C'' grade is 0.38 or less on asphalt; 0.26 or less on concrete. The grade reflects straight-ahead braking traction and not cornering, acceleration or hydroplaning.
So how useful is UTQG to consumers? Barry Harmon-who serves the wholesale accounts of Sherman Dayton Tire Sales in Sherman, Texas, and manages sales data-said he's never seen a customer refer to the UTQG grades when choosing which tire to buy. ``I'm not sure they even know what it means.''