it depends on the sole length, i cant remember the proper name for it. There should be something on the boot to say the size but if not either measure or look it up on the net. If it is only a small difference than it shouldnt matter.
What's the BSL of you AoS boots? I know the BSL of a 27.5 FT is 310. Most likely they wont have to have anything done, and if anything a simple forward pressure adjustment should do the trick.
27.5 Ace of spades have a BSL (boot sole length) of 31527.5 FT's are a 310
You'll need to adjust your forward pressure by moving the heel piece about half of a centimeter forward.Unless you are rocking FKS or your bindings are already all the way forward you should be fine.
