I’ve got my seatpost all the way up to the max extension line, but it still feels too low. It causes me to put too much weight on the pedals. If I put it past the line to experiment, is there really that much danger that it would break?
The danger is that the leverage the seatpost has on a short bit of seat tube could bend the seat tube. You probably can cheat a little, but if you’re doing stuff that puts stress on the seat post (like hopping), you might want to look at getting a longer seatpost.
I always have this problem and most of my seats are way above max. Some with only an inch in the frame!!! :0 Not ideal but for some reason I have yet to have a problem. Knock on wood. Maybe I’m not abusing them enough.
That’s because your legs are way above max. If you’ve never broken one of those, I think you’re doing pretty well.
Raising your seat a little bit above the max. line is kind of like drinking milk after the expiration date.
I have always figured if you have at least 1/2" under the bottom of the slot you should be OK.
Like anything else the line has a built in safely margin.
I’ve broke a couple of seat tubes on bike frames from running my post too high. Now I always buy the longest seatpost available, then cut it down to a length that allows for maximum insertion, while still having some downward adjustment. The length being determined by the frame’s seat tube and the height needed by the rider. As THOLUB stated, the leverage is what you need to be concerned about.
On the other hand, breaking a unicycle frame isn’t nearly as bad as breaking a bike frame; in a lot of cases you could just hacksaw off the broken bit and it would still work fine, and replacing it is cheap. So don’t sweat it too much.