KEY PARAMETERS: Tire and Wheel Model: 4.00-6; Tire Diameter 13.5"; Tire Width: 3.7"; Axle Bore Hole Diameter: 5/8" or 3/4"; Centered Hub Length: 1.75"-5.75"; Dynamic Load Capacity: 300 LBS,NOTICE: These solid tires are among the most commonly used sizes on wheelbarrows and trolleys. It is not recommended for long-time high static load. and not for highway use,PUNCTURE-PROOF & INFLATE-FREE: The solid air-less tire is made of premium PU foam, which has the features of high strength, good wear resistance, and tear resistance. So that you do not have to worry about the problem of tires being punctured,INTEGRATED WELDED RIM: These wheelbarrow wheels are equipped with SEALED CARBON STEEL BEARINGS to provide flexible rotation. And high-strength WELDED RIM to make sure it does not bend or fall apart with the hub when loading large-capacity,WHEELBARROW TIRES WITH EXTRA ADAPTER KIT: Comes with two 3/4-inch bearings and two 0.5-inch and 1.5-inch nylon spacers that can be adjusted for different wheel hub lengths and bearing holes