Yeah, I checked it, it apparently can't go below ONE second.
The more you know.

The whole build feels scattered and has no synergy. You have sunfire cape in your lategame section, but not in full build, you have an IE with no other crit items on a champ that really isn't an autoattacker. Your build seems to try to make Hecarim a jack of all trades, but it really just wastes a lot of his potential. Replacing just a few items in this build could make it all the better, but until some work is put in it won't go anywhere.

Yeah... Spirit of Dread sustain kinda contradicted yourself there. Also needs bbcoding, explain your runes, and masteries. All in all doesn't look too bad, but Its not in depth.

No sustain > Spirit of Dread -.-

Your guide turns into a wall of text at the end, try to code or use images to illustrate a teamfight.

@TheDevilex11 Rampage can never go below 2 second cd, I've tried it out with 40% CDR and I checked while having the buff up it did not go below 2 seconds

Hm.
Did you consider changing Infinity Edge for Black Cleaver or Youmuu's Ghostblade? Hecarim is not an autoattacker, Youmuu's Ghostblade syngergizes with his E and Q (he needs more of armor penetration then AD since his scaling is meh and charging with Ghost and Youmuu's Ghostblade is kinda fun :P) and he can stack Cleaver quite easily thanks to ~0.59s cooldown on Q with 2 Rampage stacks.
Also the skill order is bugging me. You complain about his lack of sustain while level 5 Spirit of Dread can heal you for quite some HP from minions, not to mention while fighting champions. Also saying that Devastating Charge is additional DPS is quite strange. I've always seen it as escape or initiate (playing Heca since day 1), sometimes when things get dire I just smack the hell outta it. In close fight, 180+(0,5*bonus AD) isn't much compared to, for example, 260 damage total on level 5 Spirit of Dread.
One last thing, the Vampirism masteries are good on Hecarim since the Spirit of Dread gains more healing out of it. A tiny bit, but it's always good.
Experiment with it and take notes.