A sheave comprising: a sheave body, the sheave body comprising: a groove; a sheave body outer diameter of ODH; a sheave bore, the sheave bore having a sheave body inner diameter IDHN, a sheave bore width of WSB and a sheave bore axis; a first circumferential surface that generally encircles the sheave bore on one side of the sheave body, and is generally orthogonal to the sheave bore axis; a second circumferential surface that generally encircles the sheave bore on an opposite side of the sheave body, and is generally orthogonal to the sheave bore axis; a two piece flanged adapter removeably and fixedly attached to the sheave bore, the two piece flanged adapter comprising: a first piece, the first piece comprising: a first piece adapter bore, with a first adapter bore inner diameter of IDSS; a first inner flange that generally encircles the first piece adapter bore; a first inner flange surface; a second piece; the second piece comprising: a second piece adapter bore, with a second adapter bore inner diameter of IDSS, and the second adapter bore IDSS is equal to the first adapter bore IDSS; a second inner flange that generally encircles the second piece adapter bore; a second inner flange surface, where when the two piece flanged adapter is installed in the sheave bore, the first inner flange surface abuts the first circumferential surface, the second inner flange surface abuts the second circumferential surface, and the first and second inner flange surfaces are orthogonal to the shave bore axis, the first piece adapter bore abuts the second piece adapter bore and forms a single adapter bore, and the single adapter bore has a width of WAB, and the two piece flanged adapter has an outer diameter of ODSS, and ODSS is about equal to IDHN. A sheave system comprising: a first grooved sheave, the first grooved sheave comprising: an outer diameter of a first value; a groove with a first groove size; a sheave bore with a bore diameter of a fourth value and a bore width of a fifth value; a sheave axis located in the center of the sheave bore; a first circumferential surface that generally encircles the sheave bore on one side of the first grooved sheave, and is generally orthogonal to the sheave axis; a second circumferential surface that generally encircles the sheave bore on an opposite side of the first grooved sheave, and is generally orthogonal to the sheave axis; a second grooved sheave, the second grooved sheave comprising: an outer diameter of a second value; a groove with a second groove size; a sheave bore with a bore diameter of a fourth value and a bore width of a sixth value; a sheave axis located in the center of the sheave bore; a third circumferential surface that generally encircles the sheave bore on one side of the second grooved sheave, and is generally orthogonal to the sheave axis; a fourth circumferential surface that generally encircles the sheave bore on an opposite side of the second grooved sheave, and is generally orthogonal to the sheave axis; a third grooved sheave, the third grooved sheave comprising: an outer diameter of a third value; a groove with a third groove size; a sheave bore with a bore diameter of a fourth value and a bore width of a seventh value; a sheave axis located in the center of the sheave bore; a fifth circumferential surface that generally encircles the sheave bore on one side of the third grooved sheave, and is generally orthogonal to the sheave axis; a sixth circumferential surface that generally encircles the sheave bore on an opposite side of the third grooved sheave, and is generally orthogonal to the sheave axis; a first two piece flanged adapter removeably and fixedly attached to any of the sheave bores of the first through third grooved sheaves, the two piece flanged adapter comprising: a first piece, the first piece comprising: a first piece adapter bore, with a first adapter bore inner diameter of IDSS; a first inner flange that generally encircles the first piece adapter bore; a first inner flange surface; a second piece; the second piece comprising: a second piece adapter bore, with a second adapter bore inner diameter of IDSS, and the second IDSS is equal to the first IDSS; a second inner flange that generally encircles the second piece adapter bore; a second inner flange surface, where when the two piece flanged adapter is installable in any of the first through third sheave bores, the first inner flange surface abuts the first, third, or fifth circumferential surface, the second inner flange surface abuts the second, fourth, or sixth circumferential surface, and the first and second inner flange surfaces are orthogonal to the sheave bore axis, the first piece adapter bore abuts the second piece adapter bore and forms a single adapter bore, and the single adapter bore has a width of WAB, and the two piece flanged adapter has an outer diameter of ODSS, and ODSS is about equal to a fourth value.