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I would suggest finding a set of wheels that have a metal sleeve on the inside where the bolt slides through.
Places like Home Depot sometimes offer a selection of them. I would bring in one of your stock wheels and see if you could match up a set that would work.
Here is a picture of one for reference:
http://www.hardwarestore.com/pop-print/larger-image.aspx?prodNo=142188
vs.
http://www.hardwarestore.com/pop-print/larger-image.aspx?prodNo=4513
I would suggest finding a set of wheels that have a metal sleeve on the inside where the bolt slides through.
Places like Home Depot sometimes offer a selection of them. I would bring in one of your stock wheels and see if you could match up a set that would work.
Here is a picture of one for reference:
http://www.hardwarestore.com/pop-print/larger-image.aspx?prodNo=142188
vs.
http://www.hardwarestore.com/pop-print/larger-image.aspx?prodNo=4513