Tire testing by the numbers

Gene Petersen, Jen Stockburger, and Ryan Pszczolkowski could probably land spots on a pit crew if they ever chose to leave Consumer Reports. The three of them do the bulk of our tire testing at our Auto Testing Division, which means, among other things, performing some 2,600 tire changes last year alone. That’s enough to routinely wear out the studs that hold lug nuts to the hubs--despite  liberal doses of silicone and careful torque wrench use. Few cars will ever see anywhere near 2,600 tire changes between the assembly line and the scrap heap. But then again, most magazines don’t buy several hundred tires for testing every year.

Regular readers know that Consumer Reports conducts the most thorough car testing program of any magazine or Web site in the United States, but even CR junkies may not realize how extensive our tire-testing program is.

For the last report, we bought 572 tires, including duplicate sets and spares. To minimize damage to the tires from changing, we also bought 150 identical wheels. The goal is to have all the tires in-house by November, to give us a couple of months to catalog and mount them. By January, we’re ready to begin.

One car was bought new specifically for the tire testing program this year, an Audi A3 for performance-tire testing. Last year it was a Honda Accord for all- season tires. Each car quickly ran up close to 14,000 miles, mostly at our track.

These are some hard miles. Days of hard braking, handling tests, flat-out acceleration and circling the skid pad in all kinds of weather take their toll on the cars, as well as the tires. The cars routinely wear through at least one set of brake pads before the six months of testing are through, and they’ve also worn out brake master cylinders, suspension parts, and at least one transmission. 

When all is said and done, the tire test car will have made more than:

·        430 trips through our avoidance maneuver course. (Note to Gene, Jen, and Ryan: Light breakfast.) 

·        860 laps around the skid pad. (Skip lunch.)

·        1450 stops from speed in the dry, wet, and even on ice. (Maybe just start fasting altogether.)

But the really big number comes from our wear testing, which helps determine how long you can expect the tires to last on your car. In 2006, we racked up a grand total of 1,120,000 miles.

At least the wear testing can be done on a full stomach.

--Jim Travers

Comments

[Dave]

Okay, now you got our attention, would you please do a blog on what tires you're impress with? Just the "first look" on cars, just on tires thought. You can have a full breakfast while doing it.

[JR]

What is the best ( safest and longest wearing ) tire for an AUDI Cabriolet A-4 2004?

[Mike]

My mechanic has recommended Kumho tires for my 2004 Monte Carlo. Specifically their Solus KR21 line. I have never heard of Kumho tires before. We do a lot of winter driving here in Wisconsin. Anyone have experience with or comments about Kumho tires?

[Joe]

I was wondering why we have such a dearth of tire information on the site - now I know - it takes a full year to get ready for and conduct a tire test ! Is there a way to mix in other tire types tested so that we can see information on high performance tires greater than every 5 years ? The last one was in 2003

[tom]

I agree with mike, maybe publish intermediate results with a pass fail or similar easy grade? I was just recommended a brand of tire I never heard of (Nokian)and would love some info. Thanks

[ken]

Many of us use our SUV's and light trucks to pull trailer RV's and log thousands of miles doing it. Are some SUV tires better than others in pulling long and heavy trailers over long distances. I can think of many questions, and hopefully, you can point me and others in the right direction regarding this important topic. MANY THANKS

[Harry Taylor]

I am upset that you recommend Q rated snow tires without any warning about the changes in handling that dropping two or three speed ratings will cause.

Q rated tires have a continuos speed rating of 99 miles per hour. Typical underinflation of five PSI will reduce the speed capacity of a Q rated tire into the high seventy to low eighty MPH range, creating a dangerous situation in clear winter conditions on freeways.

If you recommend tires with Q ratings you should alert your readers to the dangers of tires with marginal safety capacity and reinforce the need to check tire pressures regularly.

[Andy]

confused?
why do the same tires with different speed ratings test differently. Continental Conti extreme contact tires in the UHP category zr rated have a very good rating by consumer reports and the same tire in the performance category (different speed rating) are rated at the end of the category. does the speed rating of the tire change the compound that much or is this incorrect ?

[bob holden]

We are thinking about purchasing four Goodyear Viva 2 all season tires for our car, are these good, quality tires or have there been reports that they don't hold up well?
Thank you for your help,
Bob Holden

[Tom Kalligher]

I do a lot of highway and stop and go driving and need some advice on a good tread life tire without losing the other vital specs, handling, comfort, traction, ect. I purchased a set of four Goodyear Fortera tires and they lasted about a year as far as tread life goes. For the money I spent on them I was very unhappy with that aspect of the tires. I drive in Florida and consider myself a "normal" driver, not excessive speed, no hard braking, no hard take-offs, ect. Any advice would be helpful for I am in the market as I write this for a new set of tires.

[Emma Olson]

Kumho tires (225/65R17) have been suggested as alternative to Michelin for my Highlander Hybrid 2006 front wheel drive. Do not see any specific CR rating that applies. Price difference is significant. Any experience with Kumho?

Thanks

[Robert Petit]

Kumho tires are a promising brand of tires recently becoming more available in the US. They are Korean and much like Hyundai, their quality has improved significantly to the point where they can compete with some of the best well established brands. I have found that the user reviews posted by drivers on the TireRack.com website can give you useful information short of a consumer reports test-based review. You should always consider the source of the review. I recommend paying attention to reviews from drivers who have put a lot of miles on the tires they are reviewing with vehicles of similar size and characteristics to your vehicle. I also pay close attention to the rating of how likely the driver would be to buy those same tires again.
I am buying a set of 4 Kumho KR-21's for my Grand Cherokee Limited to replace Michelin Cross Terrains. I liked the Cross-Terrains, but the Kumho's are highly rated and are half the price of new Michelins.