Originally Posted By: exranger06
Originally Posted By: Astro14
Originally Posted By: JHZR2
The "speed" rating has more to do with sidewall stiffness and its effect on handling behaviors... Important for safety, no?
Glad some businesses are willing to turn jobs away to ensure that safety isnt sacrificed to save a few bucks.
You can argue going fast or handling all you want... THe vehicle was designed for a specific tire application.
Sorry.
This. Speed rating for the tire is not the same as the speed at which that vehicle can be safely driven on those tires. It's a common misconception that "I have T-rated tires, so I can drive up to 118 MPH on those tires with this car". Maybe you can, maybe you can't.
According to Tire Rack, it DOES only have to do with the maximum safe speed of the tire.:
Quote:
How to Read Speed Rating, Load Index & Service Description
Speed Rating
In Germany some highways do not have speed limits and high speed driving is permitted. Speed ratings were established to match the speed capability of tires with the top speed capability of the vehicles to which they are applied. Speed ratings are established in kilometers per hour and subsequently converted to miles per hour (which explains why speed ratings appear established at "unusual" mile per hour increments). Despite the tire manufacturer's ability to manufacturer tires capable of high speeds, none of them recommend the use of their products in excess of legal speed limits. The maximum operating speed of a vehicle must be limited to the lowest speed rated tire on the vehicle.
Speed ratings are based on laboratory tests where the tire is pressed against a large diameter metal drum to reflect its appropriate load, and run at ever increasing speeds (in 6.2 mph steps in 10 minute increments) until the tire's required speed has been met.
It is important to note that speed ratings only apply to tires that have not been damaged, altered, under-inflated or overloaded. Additionally, most tire manufacturers maintain that a tire that has been cut or punctured no longer retains the tire manufacturer's original speed rating, even after being repaired because the tire manufacturer can't control the quality of the repair.
Nowhere do they mention handling characteristics at lower speeds.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=35
Your response quotes the laboratory conditions under which speed ratings are certified. Did you notice that it's under controlled temp? Specified load? For only 10 minutes at that speed?
Real world is far different. Tires age. Inflation pressures vary from tested. Vehicle weight and load varies. Temperature varies.
So, the vehicle manufacturer specifies a minimum speed rating that accounts for those variables. It may be rated for a higher speed than the speed at which you intend to operate your vehicle.
The shop is following those guidelines.
Sorry that you don't like it.
But go back and rant at the shop owner....see where that gets you...I have always found that yelling at someone and being confrontational convinces them to come over to my point of view....
