OK but those carts could be heard a mile away with all the creaking and squealing. I was in error, the Conestogas were greased, not the ox carts. The carts contained no iron at all, being entirely constructed of wood and animal hide. The cart was buoyant and could be floated across streams, yet it was strong enough to carry loads as heavy as 1000 lbs (450 kg). Two 12-foot-long (3.7 m) parallel oak shafts or "trams" bracketed the draft animal in front and formed the frame of the cart to the rear. Crosspieces held the floorboards, and front, side and rear boards or rails enclosed the box. These wooden pieces were joined by mortices and tenons. Also of seasoned oak was the axle, lashed to the cart by strips of hide or "shaganappi" attached when wet, which shrunk and tightened as they dried. The axles connected two spoked wheels, five or six feet in diameter, which were "dished" or in the form of a shallow cone, the apex of which was at the hub. The noise was akin to the shreeching of an unturned violin.