Tires: tire size/rating, rim size, speed rating

Question
While tire shopping today 2 of 4 sales people at different stores say that
although my 2004 Avalon came with H-rated tires, I should replace with V-
rated tires.  Is this just an upsell?
Also, may I up size 1 size?  I always like to get a bit more tread on the ground
if possible.  I travel a thousand miles per week with a full load.

Answer
Mark,

The research that I performed indicates that your vehicle came with H-rated tires in either the 15" or 16" rim size options.  If you have been satisfied with the ride, performance and mileage of this speed rating then I would stay with it.

 As for up sizing, I don't see any problems in doing this provided your dealer uses the proper charts for your application.

 Up sales are a necessary part of tire sales.  However, when doing so a dealer should indicate the advantages, as well as, disadvantages of his/her proposal.  And, unless their proposal is based on a manufactures requirement or a customer need then it shouldn't be presented as a HAVE TO.