I have found that one thing with Zoot shorts is to make sure they are pulled ALL THE WAY UP and then adjust them back down in the leg. If I don't adjust the chamois/legs way into the crack of my legs (for lack of a better description) before pulling the legs to the leg line, it chafes worse than if I just yank them on really quickly, which leaves gaps and they rub somewhere else against my skin. That said, they still chafe on longer rides, and I have to use the bodyglide. I don't have chafing with my tri suit but I haven't rode it more than about 25 miles straight.

I have yet to try another brand of tri shorts, I like the quality of the Zoots. Just thought I'd toss in my two cents about how they fit. Trying something without a chamois as Knot suggests might be the best first shot.