need help with tire size please...

i have a 16 X8 inch yukon rim and i need tires what size should i go with?? i dont know shit about tire sizes... i think i need a 215-45-16 or a 215-50-16...... which one is better??? any help please.. i will be buying the tires this weekend or next but i sound pretty stupid when i call around asking for prices..lol

16x8?
I wouldn't go any narrower than 225 on a wheel 8 in. wide.
But it's supposed to be 16x7 on the Yukon...
Are you measuring the bead width, or the whole wheel?

Those wheels are 16x7.

215-50-16 would be recommended to keep your speedo fairly accurate, give you a decent ride and also look good.

Or you could do a 225-45-16, but with the Mazdas, you don't really need anything wider than a 215.