Toyota Sienna run-flat tires? Spare us.

If you subscribe to ConsumerReports.org, you can ask advice on tires under Tire Talk where our tire experts can help you make a good choice on your next set of tires. While questions on this forum cover all types of tires for cars and trucks, we rarely see a steady stream centered one car or tire model--in this case, the Toyota Sienna minivan and its original equipment tires.

Specifically, many subscribers have written to us about the all-wheel-drive models that come standard with 17-inch run-flat tires. The problem seems to be that these fast-wearing tires typically last no more than 18,000 to 20,000 miles. For some owners, that's a yearly tire purchase for their Siennas. And these tires aren't cheap to replace, typically costing over $1,000 for a set of four according to many of our subscribers. Replacement choices are limited to the original equipment model, supplied by Bridgestone and Dunlop. Both seem to wear out rapidly. The double whammy of frequently replacing tires and paying a bundle to do so is irking owners.

The two tire suppliers know of the problem. Bridgestone has at least pro-rated their original equipment tires for some owners. Many upset owners say the Toyota dealers are also well aware of the problem. We'd bet that that subject never comes up during the selling process of a new Sienna. Owners are frustrated by the lack of action taken by their dealers and the Toyota Motor Company. Even CR's letter to Toyota has resulted in silence. Oddly, Toyota now offers a spare tire kit that takes up one of the rear seats and is being sold to people who elect to buy conventional tires to replace those expensive and fast-wearing run-flats. Our local Toyota dealer estimated a cost of $900 for the complete kit (individual parts are sold separately) and cautioned that the third-row seat would have to be removed to fit the temporary spare tire and accessories. One hitch: we are not certain that conventional tires will wear any better. Yes, they are cheaper and more models are available, but you'll have to weigh that against the cost of buying that optional spare tire kit.

What should you do? Unfortunately, Toyota is being very un-Toyota-like. Sienna owners we communicated with are dissatisfied with the short tire life and the no-comment attitude of the company, which goes against the grain of the high owner satisfaction scores of the Sienna in CR's Annual Survey. If you're a Sienna AWD owner, you may want to view our forum to exchange information with others. You can also Google other forum sites for additional information. There's at least one class-action law suit that we know of. 

One recommendation that we think is a must: check your tires routinely to be sure that they're inflated correctly (low pressure will wear the tires out even quicker), and replace them when they're worn out. Some owners try to wring every last mile out of these tires, which perilously sacrifices wet- and winter grip.

Either way, we think Toyota has gone flat satisfying Sienna owners with run-flat tires.

--Gene Petersen

—Aaron Bailey