Hi,

Yeah I agree that's whats going to happen to anyone at high speed on
a 105 OC.
Personally when I made boards they always had an angled front strap
so your leg is not at an awkward angle for riding at that speed. The
OC boards' straps are both straight on so you have no choice but to
put your feet and toes pointing to the edge.

However it is much easier to ride if your front foot's toes are
facing more toward the front of the board (like the 20 degree angle
you would have on a snowboard) and I use quite a high angle. Much
more than a snowboard.

So my suggestion is to loosen the front strap a little bit more
(presuming you have the single strap version and not the multi
strap) and bring your heel more towards the back of the board while
angling your toes more toward the front and then lean most of your
weight on your back foot and just use the front one for steering.
Any weight on your front foot at high speed on a 105 board and
you're gonna hit the dirt.

A longer board would also definately help.

Let us know how you go,
Cheers
Chris