V Belt ( B-34 ) Getting damaged frequently

Make sure both the pulleys are type B, both the V are paralle to each other's and shafts of both the pulleys are parallel to each other too.

Belt is tightened as recommended.

If applicable increase both sheaves keeping the ratio the same. Change to a grip belt with the notch inside will handle the smaller diameter better. Increase the length of the belt will decrease the frequency at which any point on the belt goes around the small sheave.

GA from this side. As long as the poster understands what you meaning is. Here's a simple explanation that may make it clear;

Current application - Motor Sheave= 4", Pump Sheave= 12" 3 to 1 ratio. Lets say your motor application allows you to install a sheave up to 8.25" with out interfering with anything and you have plenty of room at the pump, ok?

In this case you would be much better off with the following;

Motor Sheave= 8.25"

Pump Sheave= 24.75"

Still 3 to 1 ratio. But with much less wear and tear on your belts and much better "traction"as well. Always make an effort to purchase "matched set" belts when you are working with multi-groove applications. Alignment and correct tension are also paramount for maximum longevity of not only belts and sheavs, but the equipment that is being driven as well.

If this is not the case, why not attach a photo and add a little more information to work with. Simply save your image to your computer then attach it to your reply by using that little green camera icon you see when posting the message