Jointer V belt replacement

Hi all. I have a Hafco 6" jointer and recently replaced the V belt as it was almost broken through (about 12 years old). It was a smooth belt and the machine has always run well and smoothly.

The replacement was a cogged one of the same length and angle. Now the machine vibrates when running and the belt seems to flap around a bit. I am pretty sure i have the tension about right.

Could the vibration be caused by the "cogged" belt? or could it be that the pulleys may have worn unevenly.

I replaced the belt on my table saw at the same time as it was a bit frayed and am getting some vibration from that as well.

Hope you can help.