I searched but could come up with nothing. I received my RVM Racing UDP this weekend, and took some measurements, and want to be able to compare. Here are my results:

Diameter- Small section= 4 7/8"
Diameter- Large section= 4 15/16"
Weight (by postal scale)= 1.60 lb.

 

I never measured the diameter of my pulley, but I did weigh it and got the same results as Greg
http://www.custommaxima.com/UnorthodoxPulley.htm
-hype

 

http://www.custommaxima.com/UnorthodoxPulley.htm
1.56 lbs, pretty close.
My bet would be they copied the Unorthodox on the measurements but I would like to know for sure.

Doooh, Hype beat me to it.

 

Does anyone have one off of the car that they can measure for diameter? FYI, I measured it in the area where the belt will actually be, not up on the lip, and I measured it at the largest point of the zig-zag pattern (this will make sense once you see one).

 

If you're trying to be exact measure the circumference. It's easier to measure without having to estimate the difference between the belt and the lip area. You could solve for the diameter from that if you really wanted to.
-hype

 

If one were to do that, it would be terribly difficult yo keep the string or wire used to determine diameter on a high point in the ridged belt area. It would have a tendency to slip into a groove, thus giving a less accurate measurement.

Also, we can use diameter to solve for circumference by the application of simple algebra. I know that we really want to look @ circumference, not diameter, but it is easier to measure the diameter.

 

Use a cloth or plastic tape measure.

 

I can do that part. Now all that we need is for someone to do the same on the UR UDP for comparison...