Yes, there is a speed rating for the tires, and it does relate to speed; but I have also learned that it relates to the thickness of the side wall.

Lower speed rating thinner side walls.

This is consistent with the comments in this thread about the weight a tire can hold, and the cornering ability of the lower speed rated tires being poorer.

__________________
Thanks for the help
Bill Fisher

'86 560SL (186K) - Now a 'classic' : Registered as an Historic Vehicle
02 E430 in the stable
'14 LS460 (Lexus)
- - - - -
'95 E420 (198K) found a new home
'99 E320 (80K) (gave it's life for me as we hit a bumper)
'95 E420 (231K) Sold to a happy buyer, new to Mercedes
'90 300E (65K) Sold to an Mercedes Lover
'92 190E (215K) - retired to the salvage yard
'93 500SEL (214K) - Moved to another family, still runs like a young pup