Lots of tire life left based on our extended tread-life test.
We’ve had a series of blog reports on our Toyota Sienna following the tread life performance of its run-flat tires. (See the links below.) Now, at just over 30,000 miles, (30,247 miles to be exact, as shown) we’re impressed with the wear performance of the tires, which are projected to wear out at no less than 54,000 miles—comparable or better than conventional all-season tires.
For those of you just joining us, we purchased a new 2007 Toyota Sienna XLE AWD with the Dunlop SP Sport 4000 Self-Supporting Technology tires (DSST)—run-flat tires. After the road test was completed, we purchased a new set of Dunlop SP Sport 4000 DSST tires for a tread-life evaluation on our Sienna. The evaluation started at the end of March 2007 and now, one year later, the tires still are trucking on.
To be fair to the tires, we have been checking inflation pressures religiously; checking alignment, rotating the tires, and measuring the average tread depth in tread grooves (four grooves) across the tire’s tread width and at four places around the tire for a total of sixteen test points. In the course of the 30,000 mile test we measured tread depth of the new tires, and then eleven times throughout the test, most at 2,000-mile intervals.
Some readers/subscribers have griped that nobody checks tires as often as we did and most certainly do not check alignments that often. To that end, we checked the tire’s inflation pressure just about every month, just like you should do. As for wheel alignment, we did check it routinely but never had to readjust the wheel alignment settings at all. And then there were our drivers, a sorted bunch of car enthusiasts, office administrators, and maintenance staff who drove the minivan all those miles.
Minivans don’t excite many employees here with all the cars that we get to drive at our Auto Test Center, but with the enticement of free fuel, people were fighting over the use of the van, especially for long vacation trips. And so the van has been all over the New England region, and it enjoyed more places than I will ever see, from venturing into the deep-south of the United States to traveling across a wide swath of Canada.
At just over 30,000 miles, the tires still have about 25,000 miles or more left based on the fastest wearing groove, before they are worn-out to the tread wear indicator of 2/32” depth. On average, just two tires were about 50 percent worn out, one was just over 40 percent worn out, and a fourth tire had to be replaced after the previous tread measurement point due to an encounter with a large pot hole. The tires were wearing faster at their shoulder grooves with a slight cupped shoulder. That continued to be the case at the last measurement, but the wear progressed more evenly across the width of the tire ensuring many more miles of happy travel.
The bottom line: Our test doesn’t guarantee that you will get the same mileage. As they say, results may vary, as the total tire range depends on how and where you drive. But given the variability of our test with different drivers, roads, and seasons driven, we feel that with proper maintenance you can enjoy a long relationship with your Sienna’s run-flat tires.
Toyota Sienna all-wheel-drive owners clearly have a beef with the short tread life of the standard run-flat tires and continue to share complaints in letters and Cars forums posts, especially in Tire Talk, the online-subscriber-only tire forum at ConsumerReports.org. We've also covered the frustration of Sienna owners regarding fast-wearing tires here in the Cars blog.
As we’ve said before, most owners were pleased with the overall performance of their AWD Sienna—one of the top-rated models in Consumer Reports tests—but few are satisfied with the run-flat tire tread life, cost of replacement, and limited models from which to choose (two original-equipment suppliers). Some even have psychological fears about not having a spare tire on board.
Many owners have complained that the run-flat tires wear out much quicker than expected or unevenly—often within 15,000 to 20,000 miles. Some owners found themselves facing an aggravating annual tire replacement, costing $700 or more. Toyota finally addressed the issue last year with an extended warranty on 2004 to some 2006 model-year vehicles, mostly addressing the irregular wear condition. Later-model vehicles came with a revised tire intended to eliminate the wear condition.
—Gene Petersen, Jen Stockburger, Ryan Pszczolkowski
Related blog posts:
Update: Toyota Sienna AWD run-flat tires
Toyota Sienna AWD run-flat tires wear well for us
Toyota Sienna AWD tires - patience wearing thin
Toyota extends run-flat tire warranty
Toyota Sienna run-flat tires? Spare us.
Run-flat tires go flat with our readers
Research tires with our expanded tools. Discuss in the Cars forums, especially in Tire Talk, the online-subscriber-only tire forum.