On the market for new tires and looked at the Hankook Optimo H418's and saw that at Tirerack they are rated among the lowest possible: at Discount Tire, they very high ( out of 5 stars). Consumer reports rates them as above average. PepBoys had 4 (235/55/17), fully installed for $516 and they rated them as an excellent tire compared to the other brands they carry.

Any theories for these discrepancies? Anyone have experience with these tires (no need to recommend others just curious about these in particular).

 

Different vendors partner with different brands. They will most likely get better deals on brands they do more volume with so they will promote that brand higher to ensure higher margins.
On the other hand, the ratings may be consumer based and the majority of buyers have no idea what they are talking about.