Was it a single or dual JP chain? How many miles did you have on it with the XP and 105's? Do you stomp on it often? And so, are you saying the JP chain itself is weaker than the rollmaster? There is a bit of price difference between the 2, but I assumed it was because of the past failures with the JP's they had to make themselves more attractive. I currently own a single rollmaster with about 5 minutes of run time and a brand new double JP.