One of my last jobs in TN it was freezing rain all afternoon and by the time we got out of there the roads were all iced and traffic backed up everywhere. Getting onto the freeway right near the jobsite was a long steady uphill grade.
We started filling up our truck beds with concrete blocks, I put about 20 in back of my half ton 87 Ranger. It eased up that long grade never slipping an inch, even tho it was slow stop and go all the way up.
Next day I asked one of the superintendents how much those blocks weighed, he came back with 48 pounds each, it was his job to know such things. Those 20 blocks had that half ton maxxed out, in addition to the tool box that was on it(same one on my 93 Ranger now)