The assumption going into the Manny Pacquiao-Ricky Hatton fight on May 2 in Las Vegas is that Hatton will have a strength advantage in the ring.

After all, the Briton is the natural 140-pounder. He’s fought at 140 or 147 his entire career. Pacquiao started his career at 106 and fought at 129 only three fights ago, when he outpointed Juan Manuel Marquez in March of last year.

Freddie Roach, Pacquiao’s trainer, doesn’t accept the conventional wisdom. He said his prot├®g├® had trouble making 135 for his fight against David Diaz last June and walks around at about 155.

Thus, he said, 140 is the perfect weight for Pacquiao at this stage of his career.

“Manny has really settled into the 140-pound division,” said Roach, speaking on a conference call with counterpart Floyd Mayweather Sr. on Wednesday. “He’s getting used to the weight. He’s knocked out four of seven sparring partners in training camp. He looks good at the weight, really strong.

“Ricky will be a little heavier by fight time but being heavier doesn’t mean stronger. I have the stronger fighter going into the fight.”

Roach thinks Pacquiao will weigh 147-148 pounds at fight time.

“He’s getting bigger and stronger all the time,” Roach went on. “One thing about Manny, he’s a lot happier when he’s not (struggling to make) weight. (At 140) he gets to eat what he wants and feels happy. That’s a good thing.”

Trainer wars: Mayweather spent much of the conference call belittling Roach, who alternately fought back and brushed off the comments.

It’s difficult to understand where Mayweather is coming from. On one hand, he says he’s just having fun and building interest in the fight. On the other, he claims he’s serious when he says Roach – a three-time trainer of the year – is not good at what he does.

“Who has he really worked with?” Mayweather asked. “He’s had a lot of big fighters but he’s not done nothing with them. He has one man, Pacquiao. Who else? What fighter has he ever made? I made my son [Floyd Mayweather Jr.]. Who has he made? He ain’t never made anybody.

“He’s just what I said, Freddie the Joke Roach Coach.”

Roach, who learned his craft from the late Eddie Futch, began working with Pacquiao when the Filipino was still relatively raw and built him into the best fighter in the world. He also built Virgil Hill into a champion and worked with many other big-name fighters.

His reaction to Mayweather’s comments?

“I know who they’re coming from so I don’t really pay attention,” he said.

Roach’s best comeback was a reference to the third Trainer of the Year award he’ll receive from the Boxing Writers Association of America in June.

“Floyd, when I get presented the Trainer of the Year award, I want you to present it because that’s as close as you’ll get to it,” he said.

Mayweather has never won the award.

Who was better?: Roach and Mayweather were both fringe contenders in their fighting days. They got in a few jabs on the conference call as to which of them was better.

“I was most definitely a better fighter than Freddie Roach,” Mayweather said. “I got a poster at the gym where Freddie fought on my undercard.”

Roach responded, “I tried really hard. I fought on TV a lot more than him. I was more popular.” ÔǪ “You were a bum,” Mayweather interjected. ÔǪ “You’re brother was a good fighter. You lost to Marlon Starling, my fighter (later on), twice,” Roach said.

So who was better? Hard to say. Neither of them fought for a major title or beat an elite opponent.

Mayweather fought from 1974 to 1985, with one comeback fight in 1990. He finished with a record of 29-6-1, with 19 knockouts. Much like his son, he had quick hands and excellent defensive skills. He was knocked out by Sugar Ray Leonard in 1978, Leonard’s first fight against a ranked opponent.

Roach, more of a hard-nosed, resilient fighter, fought from 1978 to 1986 and was 39-13, with 15 knockouts. He went the distance with a young Hector Camacho in 1985 and lost a close decision to Bobby Chacon the same year.

Mayweather was shot in the leg, reportedly by his brother in law, during a family dispute shortly after the Leonard fight and might never have been the same afterward.

“I think he would’ve been a very good fighter if he hadn’t been shot,” said Bob Arum, Pacquiao’s promoter.