Tires: Wrong tire size, tire placard, 2004 buick rainier

Question
I have a 2004 Buick Rainier and recently found out that Firestone put four new P225/60R17 tires on three years ago. I just bought four used tires this year when they told me that the 2004 Buick Rainier takes P255/60R17 tires. Over a three year span what problems can the wrong size tires have on my 2004 Buick Rainier?

Answer
Benjamin,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.

According to Tire Guides, a publication that summarizes vehicle tire placards, a 2004 Buick Rainier came with either P245/65R17's or P255/60R17's - and this lines up with what was told you.

The only problem I can see would be that the tires had an increased risk of failure - and that didn't happen.  I do not think there would be any residual problems - other than the speedometer and odometer were reading low by about 5%.  Put another way, you traveled less far and at a lower speed than indicated during the time that those tires were on, and that would be corrected with the new tires.

So unless you had some sort of ABS or engine driveability problems during that time frame - no harm, no foul.