I have worked with Helicoils. Don't beleive everthing the Helicoil Salesman tells you. With a Helicoil, or most any thread insert, you are removing the stripped threads and tapping the new hole with a larger tap that will accomodate the OD threads of the insert. There is no way that two threaded surfaces are stronger than a single threaded surface. if it were true that helicoils were stronger than the original thread, wouldn't it make sense for the crank sets to come with them already installed?