Tires: SUV tire selection, pirelli scorpion str, speed rating

Question
Mr. Smith,

My 2010 Expedition came standard with 275/55-20 Pirelli Scorpion STR tires. I'm not happy with their winter performance nor am I pleased with the wear. I've researched several other brands but the dealer cautioned my because they are T rated for speed as opposed to the H rating on the Pirelli. Although I indicated that I never come close to even driving at the T speed rating I was told that they simply won't last as long and might even be more susceptible to road damage.

Thank you for your input.

Answer
Tim,

Here's the problem in a nutshell.

For years, vehicle manufacturers under-specified the tires on their vehicles.  They put barely enough tire as far as load carrying capacity and speed rating.  The result was the Ford / Firestone debacle.

So vehicle manufacturers have changed the way they specify tires and currently newer vehicle use larger load carrying and higher speed rated tires.

Personally, it makes good engineering sense to over-specify - and I would be very hesitant to change the specification.

However your dealer is wrong about the T rated tires.  The properties that affect treadwear and road damage are not tied to the speed rating.  

But durability is!  I recommend to everyone who asks that vehicle;e used on the highway be at least H speed rated - and there are a number of tire that are H speed rated and have the other properties you are looking for.

Do you NEED an H rated tire?  No, but you are safer if you have one!