The David and Goliath scenario, with the lighter weight fighter moving up in weight to challenge the bigger fighter is something that has been occurring more frequently in boxing over the past few years. The question is, who has the advantage in this match up?
It's certainly not the rule but a majority of the time the smaller fighter is the better fighter. Clearly bantamweights aren't necessarily better than featherweights, who aren't necessarily better than lightweights. You really only start seeing the diminution of skill in the largest divisions, like when we saw Chris Byrd and James Toney fighting as heavyweights.
The variables in breaking down a bout between a lighter weight fighter moving up to fight a bigger fighter aren't all that complex. In fact, the reality is the bigger fighter is the one who's usually at the disadvantage. If by chance the fighter moving up has a cast-iron chin or is a defensive master, his bigger opponent is reduced to relying on his only weapon, his presumed overload of strength and power. If he lands and can't dent the smaller fighters’ chin he's going to lose the fight a majority of the time. The fact is, the bigger fighter is reliant on delivering his power to pull him through versus the smaller fighter.
Consider James Toney — a certifiable great fighter. Look at the good fighters he fought between middleweight and light heavyweight. He was losing to Michael Nunn before landing a lottery punch. He squeaked by Reggie Johnson and couldn't separate himself versus an old great in Mike McCallum, along with getting a decision he didn't deserve over Dave Tiberi. When he moved up a few pounds, he was schooled by Roy Jones, who was a certifiable great. Notice how against the best of the best and some middle of the road contenders fighting between 160 and 168, he didn't really shine. Fighting as an over the weight light heavyweight he couldn't do much with Montell Griffin, who will never be considered great or outstanding. He also lost a convincing decision to Drake Thadzi — a very tough and hard guy to fight, but certainly not in Toney's league.
After fighting Thadzi, Toney moved up to cruiserweight and heavyweight shortly afterward. As a cruiserweight he fought one of the best fights of his career and won a convincing decision over Vassiliy Jirov. Then it's on to impressive showings versus Evander Holyfield, John Ruiz and Dominick Guinn. After that, four tough fights with Hasim Rahman (2) and Samuel Peter (2). In those fights against big punchers like Rahman and Peter, Toney looked like Ray Robinson at times — totally outclassing them with his boxing ability and quickness. However, had Toney not been blessed with an all-time chin, he wouldn't have been around to showcase his skills.
Why is it Toney could struggle with fighters who were middle of the road fighting between 160 and 180, then move up and win more convincingly? And don't believe it's because he was weak at the weight under 180. James Toney is barely 5'9″ and didn't have trouble making the weight when he had or wanted to. He also didn't become a better fighter — he was always a special fighter. Yet he had more success at the cruiserweight/heavyweight level because he could really fight and they couldn't. And with all that going for him, he would've lost a lot of those fights if he didn't have a concrete chin because he didn't go down or out when he got nailed with some massive shots while he was resting and plotting on the ropes. Toney's success was a perfect illustration as to how inferior the level of fighting is in the heavyweight division compared to the weight classes beneath it.
Chris Byrd proved pretty much the same thing as James Toney. The difference was Chris fought much better heavyweights than Toney did, and when they were closer to their prime. Another thing Chris proved is if both the big fighter and the small fighter can fight, the smaller fighter is in trouble, something he experienced a few times. Big punchers like Bert Cooper and David Tua, who had only their power to rely on, but couldn't always deliver it — he disarmed them and took the bullets out of their guns. Physically imposing guys that were just ordinary, (Jameel McCline) or lacked desire and fortitude (Andrew Golota) he was able to handle or fight to a draw due to his fighting aptitude and toughness.
The fighters who were a nightmare for Byrd where fighters who were in their prime that could box and punch. When Chris fought Ike Ibeabuchi, he was overwhelmed by more than just size and power. The problem was Ike was a boxer-puncher who did both really well and could also put his punches together in fluid combinations. When Byrd fought Wladimir Klitschko, he couldn't cope with his size and reach. Klitschko knows how to use his size and is a decent boxer, thus making it tough for a fighter who isn't a puncher to get to him. The fact Chris Byrd could really box and had a dependable chin really enabled him to shine in the same manner as James Toney, despite always being at the physical disadvantage.
In a different era, I don't think Chris Byrd and James Toney would've been as successful or won a piece of the heavyweight title. I could never imagine Byrd holding off Joe Frazier or Mike Tyson, nor could I see Toney surviving laying on the ropes with either of them. Larry Holmes was every bit as smart and cunning as they were and would've out-boxed both. Lennox Lewis would've done the same thing to Byrd as Wladimir Klitschko, and he would've beat up a flat-footed Toney from the outside. But Frazier, Holmes, Tyson and Lewis were from a deep-era, with more complete fighters at the top.
During the last 10 years you could count on one hand the number of complete heavyweight fighters. Without question there have been plenty of big heavyweights…actually, many are too big and heavy for their own good. All heavyweights can punch, but only David Tua could be considered a genuine life-taker on the level of a George Foreman or Earnie Shavers over the last decade. An overwhelming majority of the ranked heavyweights circa 1998-2008 couldn't be considered fast or good boxers, which left them reliant on delivering their power when confronting Byrd and Toney. Only they seldom caught Byrd, and Toney had a chin from another planet; thus they were vulnerable to being out thought and fought as we saw repeatedly.
In the end, it was the boxing ability, speed and toughness along with just enough size and strength and know-how to fight that enabled Chris Byrd, who weighed 169 in his pro-debut, and James Toney who weighed 159 in his, to capture a piece of the heavyweight title during an era littered with fighters who were barely par.