I know the theroies behind it all - ive worked on enuff of em lol. The simple fact is that i have had cars where i have pulled up the handbrake and it feels perfect. However, its turned out that the drums have still been at fault. I simply wont rule out the rear drums untill they are swapped. I learnt the hard way. Friend has a concours car, with everything new from ford. We changed the WHOLE front end, and it still vibrated like mad. Handbrake was smooth. Only thing left was drums. IN all honesty i couldnt beleive it. They're cheap and easy to change though.