text: Have put 250 miles on these shoes over a few months and found toward the end the medial heel surface completely compressed such that it was affecting my knees late in runs.  Went back to my ds racers and no problems. The structure of the hyperspeeds has almost no structure in the medial heel surface so if you have any heel strike whatsoever these shoes are not for you. The shoes themself wear fairly well and if not for the heel issues, these would not be bad shoes.