Tires: Tire Load Differences, tire placard, inflation pressure

Question
QUESTION: I have a 2005 Volvo S80.  I just had 4 new ires installed.  I just noticed that the tire load rating for the new tires is 91.  The old tires were 93.

Is this okay or should I bring them back?

ANSWER: Paul,

I think I need more information:

On every vehicle sold in the US, 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.

If you'll tell me what the tire size is on the placard (inflation pressure would be good, too!), and the tire size currently on the vehicle, that will fill in a bit of missing information.

BTW, be sure to include the letters in front of or behind the tire size.

---------- FOLLOW-UP ----------

QUESTION: I'm sorry! I meant to include that info the first time.

The tire size is 215/55 R16.

Cold tire inflation pressure:

Front: 32psi
Rear: 30 psi

Thanks again,

Paul

Answer
Paul,

You didn't include the letters and the tires current on the vehicle have a letter "P" in front of the tire size.  The old tires did not.

This is one of those rare cases where this is OK.  If you want to read up on why, try this:

http://www.geocities.com/barrystiretech/loadtables.html

Pay particular attention to the graphs where I plot TRA vs ETRTO vs JATMA.  In your case, the old tires were ETRTO and the new tires are TRA.