Belt sizing

[Kahuna]

I've added a Power Steering pump to my engine.
It's not a stock pump.
What's the best way to find the correct belt size?
Run a string around both pulleys?
Use the inside or outside measurement?
Thanks
Jim

 

[miker98038]

Belts run in the V of the pulley, on the edges. My first choice would be a belt of the right width, cut and measured. Next would be a rope of the right size, (1/2" 5/8" whatever), at the smallest adjustment and the largest. Split the difference and try the belt.

 

[Kahuna]

Thanks Mike