Cut-resistant heavy-duty radial tire

A heavy-duty radial tire comprising:

• a carcass formed of a single layer of steel cord;
• at least four belts formed from steel cords and bearing most of stress of said tire;
• at least one cut protective layer disposed at an outer circumferential side, in a radial direction of said tire, of said at least four belts;
• wherein said carcass, said at least four belts, and said at least one cut protective layer are disposed so as to cross each other, further comprising:
• an outer side belt layer of two belt layers of different cord diameters which are defined by said at least four belts being divided into said two belt layers, said outer side belt layer being a belt layer of said two belt layers which is disposed at an outer circumferential side of said tire in a radial direction of said tire;
• and
• an inner side belt layer disposed further toward an inner circumferential side of said tire in the radial direction of said tire than said outer side belt layer;
• wherein said at least four belts are provided such that,
• when a belt cord diameter of said outer side belt layer is .PHI. out, an average value of absolute values of belt cord angles, which are defined by an equatorial plane of said tire, of said outer side belt layers is .alpha. out, a belt cord diameter of said inner side belt layer is .PHI. in, and an average value of absolute values of belt cord angles, which are defined by the equatorial plane of said tire, of said inner side belt layers is .alpha. in,
• a difference between belt cord angles of respective belts of said outer side belt layers is less than or equal to 5.degree., and a difference between belt cord angles of respective belts of said inner side belt layers is less than or equal to 5.degree., and the absolute values of the respective belt cord angles of said belts of said outer side belt layer are in a range of 17.degree. to 20.degree. and the absolute values of the respective belt cord angles of said belts of said inner side belt layer are in a range of 25.degree. to 27.degree., and a belt cord diameter of said inner side belt layer is in a range of 2 millimeters to 4 millimeters, and a belt cord diameter of said outer side belt layer is in a range of 4.5 millimeters to 5 millimeters, and 1<.PHI. out/.PHI. in.ltoreq.2.5, and .alpha. in-.alpha. out.gtoreq.5.degree., and (.alpha. out+.alpha. in)/2.ltoreq.23.degree. .

A heavy-duty radial tire comprising:

• a carcass formed of a single layer of steel cord;
• at least four belts formed from steel cords and bearing most of stress of said tire;
• wherein said carcass and said at least four belts are disposed so as to cross each other, further comprising:
• an outer side belt layer of two belt layers of different cord diameters which are defined by said at least four belts being divided into said two belt layers, said outer side belt layer being a belt layer of said two belt layers which is disposed at an outer circumferential side of said tire in a radial direction of said tire;
• and
• an inner side belt layer disposed further toward an inner circumferential side of said tire in the radial direction of said tire than said outer side belt layer;
• wherein said at least four belts are provided such that,
• when a belt cord diameter of said outer side belt layer is .PHI. out, an average value of absolute values of belt cord angles, which are defined by an equatorial plane of said tire, of said outer side belt layers is .alpha. out, a belt cord diameter of said inner side belt layer is .PHI. in, and an average value of absolute values of belt cord angles, which are defined by the equatorial plane of said tire, of said inner side belt layers is .alpha. in,
• a difference between belt cord angles of respective belts of said outer side belt layers is less than or equal to 5.degree., and a difference between belt cord angles of respective belts of said inner side belt layers is less than or equal to 5.degree., and the absolute values of the respective belt cord angles of said belts of said outer side belt layer are in a range of 17.degree. to 20.degree. and the absolute values of the respective belt cord angles of said belts of said inner side belt layer are in a range of 25.degree. to 27.degree., and a belt cord diameter of said inner side belt layer is in a range of 2 millimeters to 4 millimeters, and a belt cord diameter of said outer side belt layer is in a range of 4.5 millimeters to 5 millimeters, and 1<.PHI. out/.PHI. in.ltoreq.2.5, and .alpha. in-.alpha. out.gtoreq.5.degree., and (.alpha. out+.alpha. in)/2.gtoreq.23.degree. .