Dayton Daily News

Wheels: An e-mail question from JRP asks, "I bought a new car two years ago, and the tires were nearly bald after only 26,000 miles. I think tires used to last much longer. Are manufacturers using cheaper tires today? Is it true that rotating the tires will extend the life of a set of tires?"

Halderman: The short answer is yes, rotating tires does increase tire life. Are the vehicle manufacturers building cheaper tires? The answer is complex. According to Goodyear tire engineers, the original equipment manufacturers, such as General Motors, Ford, and Honda, each specify specific performance standards. These standards include:

• Low rolling resistance for best fuel economy

• Low noise

• Handling, including evasive maneuvers

• Wet handling, including wet braking performance

It is a very difficult job to design and construct a tire that meets all of these standards. Notice that tire wear is not mentioned. In fact, in many advertisements for new vehicles, there is a warning that certain tires, especially on 18 inch or larger wheels, could have a life expectancy of less than 15,000 miles. By rotating tires, especially on front-wheel-drive vehicles, the wear is equally shared over all of the tires thereby increasing the life expectancy of all four tires. However, the cost involved in rotating the tires may not be justified compared with the cost savings in tire wear. When replacing tires, look for the tread wear rating; the higher the rating, the longer the tires should last. For additional information, visit www.tirerack.com.

Wheels: Ed asks, "Can you help with this reducing mileage issue? My 1999 Toyota Corolla is losing about 2.5-plus mpg in the 2006-2007 average compared to how it ran in 1999 to 2001. I ran some mild diagnostic checks on the fuel system and the injectors and pump seem to be running the way they should. The spark plugs are two years old, but have only 15,000 miles on them. The tires are worn, but have life well above and beyond the minimum. Can you think of anything that I have missed that would recover the missing fuel mileage?"

Halderman: Fuel economy has many variables, so it would be very difficult to track down the root cause. I think there are several possible causes, including:

• The worn tires have a higher rolling resistance than tires with deeper tread.

• Weather can also be a factor because the cooler the weather, the lower the fuel economy. Ask any driver of a hybrid vehicle and they will tell you that they can almost tell the outside temperature by looking at the fuel consumption gauge.

What would I do? I would be sure that tires are properly inflated and keep the oil changed. Try a synthetic (SAE 5W-30). I hope this helps.

James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit your automotive care questions to Halderman via e-mail at jhalderman2@juno.com. or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 45 S. Ludlow St., Dayton OH 45402.