switching tire sizes would that change your gear ratio much?

[addiction2bass]

im thinking about swaping out the tires with some lower profile ones. my dad said this would change the ratio but would it be much noticable over the stock ones?
j/w
just thought about swaping out the rears with some lower profile tires and see how much it changes. my trucks just to slow and weither or not i do a rear end swap or tire change they would cost about the same. and with the lower profile the truck would sit alittle lower as well.

any comments on what you think?

[Hit Man X]

Lower profile will make you quicker also.

I usually go by 1" difference in tire height equates to 0.1 on the gear ratio differences.