are seatposts a uniform diameter or am I going to have to measure mine to make sure I get the right sized replacement? Thanks for all the help. I should be able to convince the wife that it's worth it to drop the cash on two different things (saddle and post) as money isn't really that tight, just having a hard time convincing her that bikes are more than toys and are worth a serious cash investment. Was hoping that by commuting every day that I could do that (and drop some weight at the same time).