I started out at 360 and found the length of the ride was determined by comfort (or rather discomfort) from the saddle. A move to the Brooks B17 (recommended here in a number of threads) was an eye opener allowing longer rides. At my weight I wasn't aware of having to break the saddle in however I had a more relaxed bike fit, with saddle height a bit lower than optimum. This allowed for more miles and training. Having lost 75lb, and a new bike fit, I found myself sitting differently, and again struggling with comfort, prompting a move to a Selle Anatomica. There is no need to suffer through unbearable saddle pain, more comfortable saddles are available, and yes my LBS has been wonderful allowing me to trial saddles for a number of days.