Why would you discard a perfectly good torque wrench? Since the working part is the beam itself and not the needle which is simply a fixed reference, moving the needle has absolutely zero effect on the accuracy of the tool. And the beam itself won't ever change since the flex property (Young's Modulus) is unchangeable.

Reset the needle to zero, and it'll be fine for everything short of moon rocket work. Certainly it'll be more than adequate for bike use.