I'm about 340lbs right now, no excuses. But this thing holds me up. I've done 30 miles on it, with some hard sprints on my fixie. Customer Service said none of their stuff has weight limits so I picked this up and a 130mm aero stem. I got the 400mm 0 Layback, even though most of it gets buried in the frame, I figured it would add more support. I wish they would explain a little better on how the saddle mount system works. I had to flip my piece around to go more forward. Watch the video it does help some. Once everything was set in the right position, I just went slow, back and forth on each screw until it was torqued properly. Didn't have any issues after understanding the system. It's very cleverly designed.