I am not too sure if my grinding technique is correct, I have a ronnie rim and i am currently using heatsink blues and my brake is well good for about 2 days after a new grind then it all goes pete tong. I am holding the grinder inline with the spokes and grinding round the rim, adding a fair amount of force and not just tickling the surface. The brake is set up well good too but after the 2 days the brake is just poop!! , at this rate i will be going through alot of rims in a short period of time so any help or advice would be great. Cheers people