Serpentine belt tension questions

[Rob888]

The spec serpentine belt deflection for my 2010 two door Yaris hatchback is .43-.51 inches according to my 2010 Yaris Hatchback Factory Repair Manual. But the manual does not specify the amount of force to apply to the belt when measuring deflection.

The standard recommended belt deflection is 1/64" per inch of belt length. My serpentine belt is 10.5" between the centers of both pulleys. So the deflection should be 10.5x1/64=.16". But again, the amount of force applied to get 1/64" deflection per inch of belt length is never specified.

I have a belt tension measuring tool that measures deflection when 10 foot pounds of force is applied. How many inches of deflection would be in the specified range for my car with ten foot pounds of force applied?

Thanks for any replies.