hey there, I'm looking in to grinding my rear rim. I usually run smooth with tar and plazzys but I'm thinking if it would be good with a nice sharp grind. But the only problem with grinds I seem to find, is that the grind goes dead after about 3 weeks, and then your brake is worse than ever before! (in my experience) Then you try and tar it and the tar simply goes into the cracks in the dead grind and creates a sheen of smooth tar, so your brake is even worse!!! It may possibly be the grinder and disk I used??? I dont know so any help would be appreciated thanks rob