Tires: load rating, passenger car tires, emergency maneuvers

Question
QUESTION: Hi Barry, my question is about load ratings.  I have wanli 205/40zr17 80w tires currently.  However I blew one of the tires a while back and have been looking to replace it.  I have only been able to find one with an 84w rating with all the other same specs 205/40zr17 84w.  Would it be ok to buy this tire and use it with the others that are 80w?  The car they are being used on is a 98 nissan altima.  thanks
ANSWER: John,

Considering that your original tires had a Load Index of 89, which means you ought to be using 5 psi above what the placard says - so you should be using 35 psi - then the 80 Load Index doesn't have as much load carrying capacity as the original tires, and that's a terrible idea. Besides having one odd tire tends to make the vehicle pivot around that tire in emergency maneuvers.

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

QUESTION: so if your load index is less than the stock tires or what the manufacturer suggests then you increase the psi by the difference, provided the tires can hold it?


Answer
John,

Pretty much, but you have to remember that the upper limit for inflation pressure increases to get increases in load carrying capacity is 35 or 36 psi for Standard Load passenger car tires and 41 psi for Extra Load passenger car tires.  Unfortunately the pressure written on the sidewall of the tire isn't the pressure you are seeking in this instance - That's the maximum usage pressure, which is a slightly different animal.