Lighter Side Frames: Aluminum hubs make each side frame up to 9 1/2 lbs lighter than other dollies so they're easier to lift, carry and set up. Easy, on-the-spot repairs: Key components like spindle assemblies and trip assemblies can be repaired on the spot. No more cutting, welding, or expensive trips to the welding shop. This translates to near-zero down time and no added repair bills. Lubrication of major pivot points: A lubrication groove in the shoulder bolts allows the grease to flow 360 degrees around the bearing surface displacing any moisture that accumulates. This helps prevent rusting and seizing of parts if the dollies are left exposed to the weather, corrosive road salts and chemicals without regular maintenance. Each dolly includes two side frames, two axles and a jack bar. This set has two 72-inch fixed length aluminum axles. Dollies with 5:70 x 8 tires have a 3,640 lb. lift rating.