I love the fit of these things except when I lean forward there is room in the cuff. Making the buckels tighter does not seem to help.
What are my options?
If your boot has a power strap attached to the shell, feed it inside the shell around the liner only and tighten it very snugly---this will pull you leg back to the shell and stop the liner from opening up.
Then tighten the ankle buckle to the point it hurts--- then back off till it is just comfortable---tighten the upper latch as snug as is comfortable around the liner and power strap. Doing this may pull your leg rearward and behind the boot center up position if you have slim legs.
This is why many performance boots come with a device called a spoiler---you may need to slip it in between the liner and shell to push your lower leg forward to the correct position. If you need more info you could PM me.
Question: What is the circumference of you calf when measured around the leg at the top of the liner? (use a narrow tape measure)