I have a rim brake on the back of my bmx that just wont stop me. I just replaced the pads to huge Odessey 2x4's but still no luck. The next thing i tried was sanding the pads alittle but still not alot of improvement. Next, i rubbed soda on the surface of the rims so they got sticky. This made things alittle better but i still cant stop very well at all and now it makes an annoying screeching noise when i brake. What else can i try? The rims i have are black not chrome. Can i sand the actually surface of the rim?