The speed rating shouldnt effect the required pressure. I run h rated tires but I too felt like 30psi was low. Usually I run 36-38psi in the front and 32psi in the back. No treadwear problems here.
Thanks to all. I guess my alignment guy got some advice from you guys - I had the tires balanced and the car aligned a couple weeks ago. When I went to check the tire pressure they were all at 36, so I'm guessing they set them there when the balance was done. Felt a little wierd to bleed them down but I'll go pump 'em up again. While the PCM doesn't speed limit the car we have other speed limiters here in New England: short, crappy roads with lots of curves, resulting in a higher law enforcement density :thehand: since they have lots of places to hide. Were Z rated tires specific to the STS or are there STSs without Z-rated? And if so, why?The Z/W rated option was available upto late 2003...
and Yes any car with a Z or W door sticker does not have a speed limiter:thumbsup:
Yes you had to have a STS to have any chance at Z or W rated tire... No SLSs came with "unlimited" tires... Lots of STSs (maybe most) came with slower "H" rated tires. The lower rated tires last longer, ride smoother, and tends to be quieter... GM knew that only a handful of STS owner would ever push there cars over 120 MPH... and that the previous list might be more important to most owners.... Were Z rated tires specific to the STS or are there STSs without Z-rated? And if so, why?