Cheapest way to ship wheels/tires?

I’ve shipped wheels in the past using ShipNex, and weeks after they shipped they hit me with a bogus surcharge. Any ideas on cheapest method?

ive always used fedex ground or greyhound

Depends where they are going to/from.

Internationally UPS Air-Frieght works best. Domestically UPS, FedEx, USPS or Greyhound (if you’re really saving pennies) work fine.