I got my first saddle sore and I've been riding off and on for over 20 years. I bought my new Ruby and it came with the 155 jett. I didn't know as much then and I never questioned it. When I got into the longer distances is when I got the sore. I think I saw a post and realized the jetts come in different sizes and mine was the 155. I asked my lbs and he said it was probably too wide for me based on my size/bones, etc. (5'7", 145 lbs) I do think the 143 is better but I think it had a lot to do with the shorts too. Between the saddle being a bit too wide and the chamois in the new shorts-it wasn't a good match. BTW-for my inseam length, this bike also had cranks that were too short and bars that were too wide-I won't be going back to that bike shop again. But now I'm dialed in and I love my Ruby-always did but even more now.