When lock-on grips took over, we forgot the compromises they brought with them. Their plastic core leaves less room for padding, and they can weigh as much as 100 grams more than push-ons. Where else can you spend less than $20 and save nearly a quarter pound?
The trick is to keep them from spinning. One problem is the shot-peened finish of most bars. It allows moisture to work its way under your grips, and it limits the surface area needed to keep them stuck together. Many bars are designed with mirror-smooth surfaces under the grips, but if yours aren't, you can cheat it with some packing tape.
One layer on top and one layer underneath is all it takes. Slide your brakes and shifters in, measure the length of your grip, clean your bar, and lay down a strip of clear packing tape on top, just under where the grip will sit. Very gently press the strip as far around the bar as it will reach, making sure not to leave any bubbles or wrinkles. Do the same on the underside of the bar.
It'll work best if you install them dry, but you'll need an air compressor to slide them on. Once they're positioned and your controls are back where they belong, you're ready to sit down and hold on.