It is highly likely due to user error. Many people make the mistake of having the tensioner too tight, ie no gap for the hydraulic cylinder to move. This can put severe loads on the studs causing failure. Stock or Ramey studs can fail under these circumstances. Either way, the Ramey studs are a higher grade steel and should be stronger than OE even if they were the same diameter. As long as everything is installed properly either one should function flawlessly. That said I'm running newer Ramey studs. Had a set of the gold zinc ones from Z1 and the machining was not as good as my newer unplated ones. The newer studs neck down less between the threads and the shoulder where they thread into the block and have a slightly wider filet at the shoulders as well. Not sure why there is so much variation between them.
