I have been trying an awful lot of grinding of method on 6 different bike (all the people of my local club's bikes). Now the best one after 6 months of experimenting: -Make sure you have a good clean rim (Also some rims hold the grind much better than others: for example DX32 hold the grind very well). If your rim is dirty, clean it with aceton. This is because my method does not remove material but just conditions the rim! -Then, always leave the tyre on the wheel, never take it away from the wheel or it will put some rubber from the tyre on your rim, this will result on a contaminated grind. -Start grinding, if you run an HS33, grind the rim the opposite way from when the wheel turns, if you run Vees, grind the rim the same way the wheel turns. I don't know why but both these type of brakes perform better depending on the direction you grind your rims... -Always use a brand new Metal cutting disc, about 2 or 3 mm wide. -When you grind, never push on the grinder, just let it touch your rim and move your arm around. -Choose your own angle depending on the depth of the grind you want. As you use a metal cutting disc, be careful not to put it under 30 degrees, or the disc will potentially break (and it's not funny, believe me!). -Grind all the Rim surface, otherwise, if your wheel is untrue, the pads will touch a part of the rim that is not grinded --> BRAKE FAIL! -Sand your pads afterwards to remove all the previous stuff that could be on the rims before the grind. -Take your time when griding, you don't want to damage your rim, and you'll get faster after many griding.