These cable-routing shims are designed to improve the fit of the Blue Ridge on most drop bar setups. They create a space for your housing to run in between the Blue Ridge and the shims, so that your cables don't have to bend as suddenly after leaving the wrapped section of your handlebar.
If you have drop bars with tape wrapped until pretty close to the stem (which is most drop bars) then these will probably help you fit your Blue Ridge. If your bars have a long unwrapped area in the middle, then they might not do much for you.
