They (the band) are hugely supportive spiritually and financially of the work I do, but they are in a rock 'n 'roll band, and the first job of a rock 'n 'roll band is not to be dull," Bono told British Broadcasting Corp. radio on Saturday.
"So we have to be very careful about just letting me go too far."
With fellow musician Bob Geldof, Bono was one of the leaders of this year's international Make Poverty History campaign and Live 8 concert, and he frequently makes on-stage statements about global poverty during U2 concerts.
"When I do my rant on making poverty history, I have got Larry Mullen, our drummer, behind me looking at his watch, timing me."
"I thought we would wear our audience out, but it hasn't happened," he said. "People are smart out there. They know what you are doing, they know the compromises you are making, they get it."