breaking the tire bead from the rim

hey thanks for the answers..i was leaning towards trying a c-clamp...the vise sounds good too....the answers all sounded good...i have a harbor frieght tool outlet nearby and am gonna look into a tire changing stand but,i'll try some of the clamping and warming tips this weekend.
there was a crew or actly a couple who were changing tires at a demo stand at the ama superbike finals(laguna seca).He was just stading there swapping big meaty sport tires on modern rim widths and then repeating the process..over .and over whiile taking questions.it was called a no-mar changing machine...kinda pricey "i think" it was around six hundered....i asked him about 19" rims and tubed tires and thinner rims and he said you gotta use some attachments.
Years back i used a car to break the bead and it was not my best thought out project kinda iffy on the rim and rotor..peace Craig

i did the tube type last night and for the two 73 z-1 rims with tubes the bead was easy to free up. i have some later kawi lester and morris mags i am gonna try this weekend i am hoping the clamps can get them started...any one need a pristine 11-73 z-1 front rim six hole disk pattern..i want to e-bay it cause my girl is wanting to know why i need 15 rims,and cause it is too nice to sit in my shop..how much should i ask for it?????? it is sweet and has the axle and rotor bolts with bend tabs, speedo drive tube protector strip, it is new looking? peace craig