depends on how you ride....nice and easy, no need. You may get 20k out of the stocker. However, I don't think you would be going 16/42 if you rode like a grandpa. I went with the DID zvm 530 x-ring at 7500 when I changed my sprockets...the days of chain adjusting are over, now it gets adjusted everytime I get a new back tire....about every 2500 miles.