[villagetinker]

DeanFL,
I would try this, jack up the cart so the tire is just off the ground and spin by hand, lower the cart slightly if necessary until it just touches and rotate again. If the drag is equal all the time you are spinning the tire is 'probably' OK, if it is off center, it will rub in one location. Mark where the tire rubs (tape or crayon). Remove tire, rotate 180 degrees on spindle and reinstall, repeat above test, does it rub in the same marked location? Repeat for the other tires. NOTE: you will probably have to take the rear tires off and place on the front, unless you can get the forward / reverse level between positions so the rear can be rotated, my cart will do this.
Hope this helps, send me a PM if you want to discuss this further over the phone.
PS I have the equipment to do this if you do not.