I just recently bought a pair of REI Flash Carbon trekkiing poles about a year ago. They have rubber tips, but the metal part in the center on the very bottom in the center really hits the side walk hard when walking in the city. It makes a loud noise. I ordered a new pair of rubber tips, but I don't see any way to remove the old ones. Is there something that fits over the ones that came with the poles, or do I need to figure out how to remove the old ones and replace them with the new rubber tips?