lanierb wrote:
I think the only way to get used to it is to practice it more. Just stay in the aero bars - it's just as stable if not more so - and keep your butt in the seat (unless there are bumps). Try practicing on progressively steeper hills - start at maybe 30-35mph and go up from there. It will eventually feel fine. In races I actually pull my knees in and drop my head/shoulders to get extra aero on the downhills, staying in the aero bars. It's not scary unless the wind is gusting really hard.^^^^^This.
Practice more and you will get used to it.
For me, I always felt like I wasn't as stable when in the aero position going faster. After all, my hands aren't 'on the brakes' and I'm steering with my forearms, so it's as stable but clearly feels different. I routinely ride my Zipp 808's on my cervelo P3 (*prior to that my P2) all year-especially in the spring when it's windy, to get used to crosswinds at speed. And every year on those first rides, my heart would pound and I thought that I'd lose control...but I didn't. I live in a hilly area and I routinely hit > 40 mph on EVERY ride now-with a peak of 50+ at IMLP before the roads were paved on the Keene descent (oh, it's so nice now comparatively).
Practice, practice and practice more.