Tires Q&A: Can I replace one or two tires at a time on my car?

Consumers Union held their annual open-house tour on Saturday, October 17 at the company headquarters in Yonkers, New York. Visitors got a chance to tour various stations to hear how Consumer Reports tests different products. It’s always a nice opportunity to talk about how we test tires at this event and as in past years there were a lot of interested visitors looking for more information on tires, particularly on how to buy.

Question: By far, the most common question asked this year was: “Is it OK to purchase just two tires at time?”

Answer: A simple question, indeed, and the simple answer is yes you can in most cases--but there are many considerations.

Most importantly, CR recommends rotating tires routinely following the guidelines spelled out in your vehicle’s owner’s manual, typically every 6,000 to 8,000 miles. The owner’s manual will have a rotation pattern to follow as well. Following the routine rotations will optimize a tire’s tread life and will wear all four tires evenly. Bottom line: when it comes time to replacing the worn-out tires, buy four new ones.

Many drivers may not rotate tires at all or not on a routine schedule. Owners of front-wheel drive vehicles will likely be replacing the front tires two to three times more often than the rear tires --since the front tires are doing most of the work by driving the wheels, doing most of the braking, and steering the car. The rear tires have a much easier life, being generally lightly loaded and free-rolling. In this common scenario, where only two tires are worn out and need replacing, CR recommends at least purchasing new tires of like brand and model as those already on the car, despite the best practice of purchasing a full set of four new tires. Mixing tire brands or even different models may cause handling instability. And when replacing only two, we recommend installing the new tires in the rear and placing the (older but still decent) rear tires in the front. This may help prevent a spinout or oversteer condition on slick roads. Both these recommendations apply to rear-wheel drive vehicles as well.

Finally, if you own an all-wheel drive vehicle, the first step before buying a new tire or pair of tires (short of installing four new ones) is to read the vehicle’s owner’s manual. Many makes of all-wheel drive vehicles will stipulate that all four tires must be of the same size, brand, model, and state of wear. Any deviation could result in an all-wheel drive system failure due to the stress placed on it from rotating dissimilar overall diameter tires.

Now wasn’t that simple?

To see full details on all tire models we tested, check out our Ratings and recommendations (available to subscribers). In addition to our updated Ratings, all site visitors can access our free buying advice for tips on getting started, types of tires we test, features that are important in making a tire purchase, and general tire care. Also, be sure to check out our TireTalk forum to interact with our tire engineers and other drivers.

—Gene Petersen 

2009 SEMA Show: Tire testing and the transformation of the tire industry

Every year Consumer Reports’ tire team attends the Specialty Equipment Manufacturers Association (SEMA) show in Las Vegas to meet all the tire manufacturers under one roof. It is an effective way to have face time with industry members, learn about upcoming developments and products, and shape our upcoming tire programs. With these insights, we will soon have outlined the tire models that we will be testing for the next major tire report due next year. This much we do know: we’ll be covering ultra-high performance models, including summer, all season, and performance winter tires.

The dismal economy shaped this year’s SEMA show. Big names such as BFGoodrich, Bridgestone, Continental, Dunlop, Firestone, Goodyear, Michelin, and Yokohama were noticeably absent. (Read “2009 SEMA Show: Tire coverage.”) 

But not all companies followed that trend. Cooper had a dominant front entrance booth and was creating a big draw from its major sponsorship of the PBR (Professional Bull Riding) rodeo that was in town the week of the show. Pirelli was there, as in previous years, but employees were dressed in refreshing business-casual attire unlike previous years when the mandatory suit almost made the booth seem overly serious. Pirelli was touting green performance this year. “Green” products seem trendy, but Pirelli’s tact was to demonstrate its new Scorpion Verde All Season tire for SUVs and truck—a tire that is energy efficient and has low noise transmission, but supposedly does not compromise tread life and all-weather grip.

Also present was Hankook, a maturing tire company offering a full array of tire products for aftermarket and original equipment markets. Most Americans’ would be shocked to know that Hankook is the seventh largest tire manufacturer in the world, with record sales tallied in 2008. It perceives itself as the next-generation tire company, growing significantly even during these rough economic times. Upcoming companies like Falken, Maxxis, and Nexen also commanded attention at this year’s show as major contenders in the post-recession period. Nexen plans on developing new tire models dedicated for the North America market soon. They created traffic at their booth with a silly 15-series performance tire in a 365/15R24 size they created—think of an elastic band around a wheel.

Overall, it seemed like the underlying mission among manufacturers was to make a statement of confidence to tire dealers and attendees, moving forward with new products, and a commitment to succeed despite the poor economic conditions. A threat to the big names missing at the show, maybe, but even the major companies present could see the irony by looking down the hallways of the convention center to see so many newcomers. These companies are not household names yet, but can you imagine someday buying tires with brand names like Sunny, Hankang, Linglong, Triangle, and Wanli? Stay tuned.

For Ratings, recommendations, and buying advice on car, truck, and winter tires, see our tires section.

—Gene Petersen

Also see from the 2009 SEMA show:
Better than expected, future looks greener
Our favorite modified Chevrolet Camaros
New iPhone apps for auto diagnostics
World's fastest Honda Civic circa 1976
All shades of green project cars
Surfrider Toyota Camry hybrid CNG
Kustomizing the Toyota Prius
Hot rodders turning green
Auto aftermarket prepares for show time in Las Vegas

Tires Q&A: Tire rolling resistance

In our ongoing series of Q&A blog columns, we will highlight common and interesting questions posted to our Car forums, with answers from our automotive experts.

Question: I bought four Yokohama Avid TRZ tires just two weeks before the 11/09 Consumer Reports issue arrived. I'd read reviews on the internet but none addressed mileage. As I drive an ‘04 Prius, mileage is very important. I had been trying to figure how new tires would drop my mileage a very noticeable 10 percent (from 53.3 to 48). Had I only known the tire ratings were coming I would gladly have waited and would definitely have different tires today.

Answer: I’m sorry the report did not reach you in time of your tire purchase. Until the State of California or the federal government comes out with rolling resistance regulations and ratings, your only sources for rolling resistance information on tires are from manufacturers’ claims and Consumer Reports. Our testing is comparative among the models tested.

Yes, you could have purchased a more fuel-efficient tire, but the Yokohama Avid TRZ is average among all season replacement tires for rolling resistance. Some were better--such as the top-rated Michelin HydroEdge, and the Toyo Versado LX. One point to consider when replacing tires: As tires wear out, you’ll likely see improved fuel economy since the tires will have less rolling resistance as the tread (mass) is removed from the tire. Installing new tires, identical in brand and model as those removed, and you likely see a reduction in your fuel economy. The new TRZ tires should become more fuel efficient as the tires wear. Also, keep the tires properly inflated and check them monthly to get the optimum fuel efficiency.

To see full details on the tire models we tested, check out our Ratings and recommendations (available to subscribers). In addition to our updated Ratings, all site visitors can access our free buying advice for tips on getting started, types of tires we test, features that are important in making a tire purchase, and general tire care. Also, be sure to check out our TireTalk forum to interact with our tire engineers and other drivers.

—Gene Petersen 

Tires Q&A: Tire-testing vehicles

In our ongoing series of Q&A blog columns, we will highlight common and interesting questions posted to our Car forums, with answers from our automotive experts.

Question: Has CR tried using different cars, but same size tires to see if the relative ranking would change dramatically?

Answer: Our tests are designed to judge tire performance on a comparative basis. Our goal is to use a popular and suitable car and appropriate tire size that also best represents the segment we are evaluating. Hence, we use one car or truck as the test calls for.

From our experience, a car’s natural abilities in terms of handling and ride comfort would influence the results, but it would be an offset in the comparative ratings between one car model to another. Also, differences in vehicle weight, wheel alignment, and drive-wheel configuration could affect a number of tests like snow traction, ice braking, and hydroplaning resistance. But, again, the comparative results should be maintained. The same holds true for our tread life test that’s done on like vehicles under identical conditions and is strictly a comparative test. Rolling resistance is the only test done without a car, performed on a dynamometer, so there is no vehicle effect.

More recently we have seen stopping distance reversals of tire models when used on different cars. This generally happens with tire models that are somewhat close in braking performance, and our data suggests a grippy tire is generally good on a wide variety of cars. But today’s cars have ABS brake systems tuned to a specific peak friction characteristic. To judge the tire’s peak level of grip we now do a “best effort” stop on dry and wet surfaces. A best effort stop has the driver modulate the brake pedal effort to get the shortest stop without wheel lockup, evaluating each tire model to its own peak friction level.

Comparative testing works well if you can remove or compensate for the vehicle effects as we strive to do. Publishing actual data would be misleading because it applies to the specific vehicle used.

Ratings, recommendations and buying advice on car, truck and winter tires, see our tires section.

—Gene Petersen  

2009 SEMA Show: Tire coverage

Every year Consumer Reports tire engineers trek-out to the Specialty Equipment Market Association (SEMA) show held in Las Vegas usually in the first week of November. The show is the premier industry event for aftermarket automotive products. This non-public event attracts well over 100,000 people who work in the automotive industry.

We go there every year to meet with the tire manufacturers, discuss upcoming tire testing programs (including what tire models to test and trends and challenges facing the industry as a whole), and to view new tire-related products that might be interesting to evaluate. In previous years, nearly every major tire manufacturer would attend, each with their own flashy booth, exotic cars shod with their newest tire models, and sometimes have scantily dressed models to help draw in the floor traffic. 

This year, coming off the heels of the worst recession since the Great Depression, many tire manufacturers are struggling to make a business case to attend the show and as a result many won’t be there. BFGoodrich, Bridgestone, Continental, Dunlop, General, Goodyear, Kumho, Michelin, and Toyo will not exhibit this year. That will put the lime-light on Cooper, Hankook, Pirelli, Maxxis and Nexen.

We’ve seen the automotive landscape change this year in a historic way with the restructuring of GM and Chrysler. Maybe times are a changing in the tire industry, too, as reflected in the companies that will (and will not) be at the show.

We'll bring you the latest tires coverage from this year's SEMA show, which runs from Nov. 3rd through Nov. 6th.

—Gene Petersen 

Tires Q&A: Run-flat tires for Corvette?

In our ongoing series of Q&A blog columns, we will highlight common and interesting questions posted to our Car forums, with answers from our automotive experts.

Question: My first Corvette has Michelin Pilot Sport A/S Plus. I’m considering using the same tires but in a run flat, but I hear bad things about them. Any feedback would be appreciated.

Answer: In short, the virtue of a run-flat tire is extended mobility with no need to worry about being stranded with a flat tire. If you have my luck, the tire will go flat on a rainy, cold night over a dangerous section of road--and you don’t get to choose when a tire goes flat. Run-flat tires can handle a puncture or road-inflicted damage and allow the driver to make it to a service station or final destination. That’s the payoff of having run-flat tires.

Our experience is that some applications work better than others. The Corvette C5 is a perfect candidate for run-flat tires as there’s not much room for a spare tire, let alone room for tossing in a full-size flat tire inside the car. Run-flat tires are stiff by design to support the weight of the vehicle with no air pressure. For the Corvette, which uses stiff, low-profile ultra high performance tires, a run-flat is not much of a trade-off in terms of ride comfort and handling, even when it goes flat. Also, the Corvette was designed to accommodate run-flat tires, so it should be your first consideration when making a new tire purchase.

See our run-flat report to learn more about on the pros and cons of run-flat tires. For Ratings, recommendations and buying advice on car, truck and winter tires, see our tires section.

—Gene Petersen 

New tire ratings and a new look

Our new redesigned tire product page has launched and offers a new look and additional information that will help users make good choices in purchasing new tires. As with the previous design, subscribers can view recommended models, Ratings and overall scores, but with the enhanced functionality, you can now select each model to view a photo of the tire, see features and specifications including available sizes, as well as a “CR’s Take” and Highs and Lows of each model. We have also added User Reviews—which allows consumers to read reviews and experiences for the models you are considering or a write review yourself.

Powerful new tools have been added to the left side of the Ratings charts to take the guess work out of comparing tires. You can now filter models by Brand, Price, Feature (speed rating, warranty, etc.) and by performance Rating (dry brake, wet brake, etc.). 

We invite you to test drive our new tire section, where you’ll see new Ratings on all-season, performance all-season, and winter tires (which will appear in the November issue of Consumer Reports magazine). Michelin tires swept the categories of all-season, performance all season, and winter tires, among 69 models—the largest group ever tested by Consumer Reports. To see which models are tops our tests, check out our Ratings and recommendations (available to subscribers).

In addition to our updated Ratings, all site visitors can access our free buying advice for tips on getting started, types of tires we test, features that are important in making a tire purchase, and general tire care. Also, be sure to check out our TireTalk forum to interact with our tire engineers and other drivers.

—Gene Petersen

Tires Q&A: Problem solving irregular wear

In our ongoing series of Q&A blog columns, we will highlight common and interesting questions posted to our Car forums, with answers from our automotive experts.

Question: My Mazda RX-8 is showing tread wear on the outer edges of the tire. Wheel balance, right? Wrong. I paid $50 to find out that all the wheels are within specs. I consistently keep the inflation between 32-34 lbs so that can't be it. The shop guy said "bad tires." They are original Bridgestone Potenzas. Could he be right? I don't know where to turn next.

Answer: Tire wear issues like that mentioned above are all too common and often the blame goes to the tire manufacturer if there is no apparent easy answer. That’s too bad since it can be avoidable most of the time. Most experienced tire dealers can diagnose the problem just like a doctor does with a patient – mostly by observing and narrowing down the possibilities.

In this case, the tire wear pattern tells the story. The fast outside shoulder wear suggests a wheel mis-alignment. The owner said that the tires received an alignment, which was deemed in-spec but not on-spec. Often that might not be good enough for some cars and the owner and consumers alike should request that wheel alignment be adjusted back to the middle of the alignment specification or as close as possible. In other words, sometimes “close-enough” isn’t good enough. The RX-8 owner isn’t alone. We just recently examined a police cruiser that had a similar wear problem. The officer had the cruiser checked for alignment and was told it was within tolerance but not to the exact specification. Ironically, the alignment shop told the officer that the tires were probably the problem and replaced them. Guess what? The new tires were starting to wear like the old ones. We told the officer to have the wheels re-aligned to the exact specification and to have the shop check for any worn suspension components while they were at it.

Bottom line: Sometimes you have to be persistent. The red flag in both examples was that the alignment was checked, but the shop didn’t put the effort into re-aligning the car to the exact specification. Look at your tires, particularly their wear, as they can tell the story.

—Gene Petersen

Tires Q&A: How to choose the right tire for a Honda Odyssey

In our ongoing series of Q&A blog columns, we will highlight common and interesting questions posted to our Car forums, with answers from our automotive experts.

Question: I'm looking for some advice about tire sizing. I'm very interested in using the Michelin HydroEdge tires on my 2003 Honda Odyssey van. However, the size available for my van (225/60R/16) does not meet the load rating requirement.

I've noticed a lot of people are using this tire on the van over at TireRack, but I haven't seen any mention of the sizing. If I were to go up to a 235/60R/16 I would meet the load rating.

My question: Will there be any negative consequences of moving to a slightly wider tire? Perhaps lower mileage?

I'm also interested in the Goodyear Assurance TripleTread but the same issue applies for this tire.
 
Any good advice for choosing tires for this van? I'm looking for something that will last a good while and be very good in the rain.  

Answer: This issue is to swap-out Euro-Metric tires for P-Metric tires on the Honda. The Odyssey came with Euro-Metric tires, also called “Hard”-metric tires by some. This size designation is common in Europe, whereas in the U.S. a “P” precedes the size designation. The two size designation systems are similar, but not the same, adding to the confusion of making a tire purchase.  

In the case of the Odyssey, replacing the Euro-Metric original equipment tire with the same “size” P-metric version would result in load capacity shortfall of 44 pounds. (The load capacity and load index, a code that coincides to the load capacity both can be found on the tire’s sidewall.) Multiply that by four tires and the load capacity in down 176 pounds.   Most tire retailers may sell the tire in the two designations interchangeably, but tire manufacturers won’t recommend switching. Our advice when buying new tires is to follow the recommendations made by automobile manufacturer by replacing tires with the same size and load index as listed on the tire placard. The placard is usually found on the door jamb, under the fuel fill cover or in the glove box of most cars. With this knowledge, you can find a tire that best meets your performance and budget needs in our ratings.

—Gene Petersen

Before buying, be sure to consult our car, truck, and winter tire ratings and buying advice. And check out our new, interactive tire ratings tool.

Car tires: All-season and winter tire ratings are coming soon

Many astute readers who commonly visit Tires & tire-talk forum are aware that it’s almost time to release our new tire ratings. And this year we have an extensive list of new tire models. To be exact, 69 new models were tested and rated.  The tire test results will be included in the November issue of Consumer Reports. (See our current car tire buying advice and ratings.) 
 
The new report will include 23 models of standard all-season (primarily T-speed rated) tires, 29 H- and V-speed rated performance all-season tires, and 17 winter tires.
 
Last year we promised to shorten the test cycle to provide major updates every three years rather than four and five years that were customary before. The three-year cycle covers three major categories: standard car tires, ultra performance tires, and truck tires.  And as the cycle goes, last year we tested truck tires, this year is car tires, and next year expect to see a report on ultra high performance tires. Here’s a glimpse of the tire models you can expect to see in the November issue, as well as online in October.

Standard all-season tires (T-rated)

 BFGoodrich Traction T/A
 Bridgestone Turanza EL400 
 Cooper CS4 Touring  
 Cooper Lifeliner GLS 
 Dunlop SP 60
 Falken Sincera SN828  
 Firestone FR710 
 General Altimax RT 
 Goodyear Assurance TripleTred 
 Hankook Optimo H727 
 Dayton Quadra LE 
 Kumho Solus KR21 
 Maxxis Escapade MA-T1 
 Michelin HydroEdge 
 Pirelli P4 Four Seasons 
 Pirelli Cinturato P5   
 Sumitomo HTR T4 
 Toyo Versado LX 
 Toyo Extensa A/S  
 Yokohama Avid T4 
 Yokohama Avid TRZ 
 Yokohama Avid Touring-S  
 Uniroyal Tiger Paw Tour SR  

Performance all-season tires (H-rated)  

Continental ContiProContact 
Cooper CS4 Touring 
General Altimax HP  
Michelin Primacy MXV4 
Hankook Optimo H418  
Nokian WR G2  
Goodyear Assurance Fuel Max 
Falken Ziex ZE512 
Falken Ziex ZE912 
Fuzion HRi
Pirelli P6 Four Seasons 
Kumho Solus KH16 
Michelin Pilot Exalto A/S   
Yokohama Avid H4s

Performance all-season tires (V-rated)  

Bridgestone Turanza Serenity   
Continental ContiProContact   
General Altimax HP   
Toyo Versado LX   
Goodyear Eagle ResponseEdge   
Kumho Ectsa LX Platinum  
Hankook Optimo H418   
Bridgestone Potenza G019 Grid   
Dunlop Signature  
Firestone Firehawk GTv   
Fuzion VRi 
Goodyear Eagle GT   
Pirelli P6 Four Seasons   
Michelin Pilot Exalto A/S   
Yokohama Avid V4s

Winter tires (Q, R, S, T rated) 

Bridgestone Blizzak WS60   
Continental ExtremeWinterContact   
Cooper Weather-Master S/T 2   
Dunlop Graspic DS-2   
Firestone Winterforce  
General Altimax Arctic   
Goodyear Ultra Grip Ice   
Hankook Winter i*Pike   
Michelin X-Ice XI 2   
Toyo Observe G-02 Plus   
Yokohama ice Guard iG20   
Gislaved Nordfrost 5   
Nokian Hakkapeliitta 5   
Nokian Hakkapeliitta R  

Winter tires (H-rated) 

Hankook icebear W300  
Pirelli Sottozero 210 Series II   
Michelin Primacy Alpin PA3

We tested all tires in the popular P215/60R16 size. Our tire-test cars included a 2008 and a 2009 Chevrolet Malibu. Testing 69 models was no easy task. We purchased 976 tires, mounted and balanced over 360 tires, and performed over 3,200 tire changes at our track, not counting the tires we commission an outside laboratory to test for rolling resistance and tread life. Test preparations started last November and the testing was completed in July. Overall scoring of these tires will include results from dry and wet braking and cornering, snow traction, ice braking, hydroplaning resistance, handling, ride comfort, rolling resistance and tread life.

We are still working on compiling the results. Expect a few surprises as many of the models have never before been tested. 

—Gene Petersen

Before buying, be sure to consult our car, truck, and winter tire ratings and buying advice.