Question about 20" rims... ???

[Hazieview]

I have a question about putting 20" rims on our chevy trucks. If you put 20" rims on lets say a stock '87 chevy pickup wouldn't you have to upgrade your brakes or no? I know it all depends on weight but I am sure that a of 20" rim would weigh a considerable amount more than a 15" steel wheel which the brakes where designed for right?

Just wondering because if I decided to spend a couple grand on 20's I hate to find out I have to spend another grand on brakes. Any help would be appreciated. Thanks!