David Haye’s moment has come and regardless of how it turns out,  it will be a weighty one.

The former all-but-undisputed cruiserweight champion boasted for some time about what he would do if he ever laid his hands on heavyweight champions Wladimir and Vitali Klitschko and then ducked both of them after agreeing to fights with each so he could instead face the far less formidable of the reigning champions, WBA titleholder Nikolai Valuev. Tonight in Nuremberg the boxing world will learn if that was a wise calculation by the British-born Haye or simply a massive undertaking for which he was ill-prepared.

Friday night in Germany the two weighed in and the hard-punching Brit with the sometimes suspect chin was barely one stone (14 pounds) above the cruiserweight limit of 200 pounds. At a tad under 217, he appeared fit and fierce. What he did not appear to be was a guy who belonged in the same ring with a towering presence like Valuev. That doesn’t mean this will prove to be the case because in boxing looks can be deceiving and size does not always matter.

Still, Valuev stands seven feet tall and weighed in at 314.6 pounds, nearly 100 pounds more than Haye, who never looked more like a junior heavyweight than he did standing next to a guy whose head seemed like it would not fit on Haye’s neck.

To his credit, Haye has said repeatedly, “I don’t care what I weigh. I haven’t looked at the scales’’ so when Valuev came up weighing a full straw-weight more than Haye he was already prepared for the discrepancy. Whether he’s still ready tonight remains to be seen but Haye understands an important thing about boxing. He understands it’s a sport more about speed than size, more about explosiveness than brute strength.

And in those areas Hayes (22-1, 21 KO) seems to have it all over Valuev. The question is whether the Hayemaker can get close enough to Valuev to make those things a factor because Valuev has more than a straw-weight advantage over him. He also has an 85-inch reach, a five-inch advantage over Haye that the cruiserweight will have to find a way to overcome.

How to do it, he believes, is obvious. Whether he can or not remains to be seen.

“He’s never fought anyone as fast or who punches as hard as me,’’ Haye insisted this week and, frankly, he’s probably right. In boxing, speed is power and Haye has both, the latter being generated by the former.

He also has the kind of athleticism that seems likely to give the ponderous moving Valuev (50-1, 34 KO) trouble, although everyone who has been in with Valuev felt the same was true and left the ring admitting the  two-time champion was a better fighter and more difficult opponent to face than they thought.

Haye may find the same is true for him, especially since he’s more than nine inches shorter. To give away nearly 100 pounds in weight, nearly half a foot in reach and more than that in length is, well, to ask for trouble but that is what boxing is. It’s a willing acceptance of trouble, or at least the potential for it.

Haye understands that but he also understands the gamble he made by walking out on arranged fights with both Klitschko brothers in the hope of picking up a third of the title first to improve his negotiating position was a wise gamble. It may not pay off but don’t tell that to the Hayemaker, who has insisted ever since the fight was agreed to that “I’m going to make him look silly. I’m going to embarrass him. People physically can’t see how I can beat him. They can’t see how I can get close enough to hit him.

“I’ve never fought anyone his size so I’ve got to make up for the physical limitations by going at him with things he’s never seen before. I’ve got to punch from different angles with ridiculous speed.. I’ll do it with fast, explosive movements and cleverness.’’