HD rotor & LD rotor measurments

[Lowl!f3]

Where are these measurements taken to find out which rotors your looking at?
Is this talking about thickness or edge of the rotor? The bearing opening?

3) Rotors: There are two different widths of rotors available on the 73-87 model trucks.
3.1) HD or Heavy Duty rotors: (1-1/4" wide version) available from 73-87
* These will require matching HD bearings and calipers.
3.2) LD or Light Duty rotors: (1" wide version) available from 81-87.
* These will require matching LD bearings and calipers.

[chevy_mike]

On a new rotor, these would be the thickness of the rotor face. Now if you have used rotors, there could be enough wear that the thickness could be less than what is listed so it's not as easy. I know the bearings are different sizes but don't know those measurements off the top of my head.

[Lowl!f3]

Well they are used, so they must be the HD rotors. I didn't get down on the rotor. I just threw a tape on it and it was what looked like close to 1-1/2". So I would say they are definitely over 1" thick.

[chevy_mike]

Sounds like the HD (thick) rotors.