Lets just say that I wanted to "validate" the size of my tires. How do you measure the diameter. Parallel to the ground or perpendicular? I'm thinking parallel, but I'd like to here your thoughts. I know I can read the markings on the tire and look up the size on line. I want to be able to compare the two numbers to see how accurate they are.
Right now my 58 Suburban, '78 250 six, stock 3 on the tree and stock 3.90 rear, runs at 3,000rpm at 55mph according to the GPS. I have been told "you're running pretty short tires." They are cool looking white walls, but not that great for highway cruising. The speedometer in the truck also reads 5mph fast. So at 55mph on the GPS it reads 60mph. I'm thinking that if I get a little bit taller tires I can correct the reading and get a little better cruising revs.
On a related note, I'm running all stock original drum brakes. The truck stops straight and even. I think the previous owner did a brake rebuild before I got it. It actually drives quite nicely on the road.
