Tiki eager to pass torch, sort of BY RALPH VACCHIANO DAILY NEWS SPORTS WRITER Tiki Barber turned 30 last month, and he knows that's traditionally the age when running backs' careers begin to slide. That's why he's in favor of anything the Giants can do to help extend his NFL life. "Absolutely," Barber said. "I want to play another four or five years, and if I keep getting 330 (carries), or whatever I've had the last few years, my body is going to break down. It's just physics. I'm not against doing it, because all I want to do is win and I know by being on the field I help us do that. But it's good to have help." Help arrives this morning when Brandon Jacobs, the mammoth running back the Giants drafted in the fourth round two weeks ago, takes the field for the start of Big Blue's three-day rookie minicamp. The veterans have the week off, so Barber won't be there to see the 6-foot-4, 267-pound rookie who insists he can run a 4.4 in the 40. But he's hoping Jacobs will be good enough to fill the short-yardage running back role. "It'll be interesting to see how he performs on this level because there's been a trend away from big backs," Barber said. "There are more 5-10, 6-foot guys who are agile. So we'll see if he can keep up with the pace. But I'm excited about him. I think he'll help with some situations, like short-yardage and goal-line." Barber had those roles by default last season due to the failures of Ron Dayne. He had every other role, too, as he touched the ball on 39.5% of the Giants' plays. This offseason, the Giants were determined to lighten that load, which is why they drafted Jacobs out of Southern Illinois. Veteran Mike Cloud likely will be Barber's primary backup, but Jacobs and second-year pro Derrick Ward (5-11, 233) will battle it out for the short-yardage role. And that's a crucial role considering the Giants converted just 48% (13-for-27) of their third-and-1 opportunities last season - the second-worst percentage in the league. Barber believes Ward and Jacobs "will push each other and hopefully give us a powerful punch in the backfield." He also hopes they'll allow him to occasionally step off the field. "I think the best teams in this league truly have two or three guys that can go in and contribute just in case something happens," Barber said. "You know, we've been lucky. I've been healthy the last three years." Notebook MEET & EAT: Barber will spend tomorrow night at Brandon Steiner's "Dream Builders" barbecue in Scarsdale along with other sports legends to raise money for Family Services of Westchester's Boys Residence in White Plains and Camp Sussex in New Jersey. Call 914-307-1010 for tickets.