Thanks for all the advice! I did neglect to add that the deck was not engaged as I was towing a yard trailer with garden soil. No, haven't been to the Cat scales but I guess I could load it on the utility trailer and make the trip.
As this blow out occured on the steer axle I didn't think it was relevant as no WDH on the trailer (only effect of hitch wt would be a wheeli)
but the tractor does have an OEM front weight attached. Maybe I should check into a set of Bilstin's for the front.