"This Marathon Tires Flat-Free Semi-Pneumatic Wheel never goes flat, keeping hand trucks and carts rolling along. Bore Diameter in. 5/8, Load Capacity lbs. 200, Outside Diameter in. 10, Hub Width in. 2.3, Tire Size 10 x 2.75, Tread Type Ribbed, Tire Type Solid rubber, Rim Size in. 4, Rim Included Yes, Grease Fittings No, Bearings Included Yes. Made of heavy-duty solid rubber Steel rim with 5/8in. ball bearings 2.3125in. centered hub"