A one-piece tensioner adjuster comprising: a plate portion comprising an opening for receiving a fastener for installation of a tensioner; a first neck portion extending from the plate portion; and a second neck portion extending from the plate portion on a side of the plate portion opposite from the side of the plate portion from which the first neck portion extends; characterised in that: the first neck portion is a first curved neck portion and the second neck portion is a second curved neck portion; wherein the tensioner adjuster further comprises: a first guide portion extending from the first curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; a second guide portion extending from the second curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; (i) a first reinforcing support (58a2) that extends from the first curved neck portion; (ii) a second reinforcing support (58a3) that extends from a side of the first curved neck portion that is opposite the side from which the first reinforcing support (58a2) extends; (iii) a third reinforcing support (58b2) that extends from a side of second curved neck portion; and (iv) a fourth reinforcing support (58b3) that extends from a side of the second curved neck portion that is opposite the side of the second curved neck portion from which the third reinforcing support (58b2) extends. a plate portion comprising an opening for receiving a fastener for installation of a tensioner; a first neck portion extending from the plate portion; and a second neck portion extending from the plate portion on a side of the plate portion opposite from the side of the plate portion from which the first neck portion extends; characterised in that: the first neck portion is a first curved neck portion and the second neck portion is a second curved neck portion; wherein the tensioner adjuster further comprises: a first guide portion extending from the first curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; a second guide portion extending from the second curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; (i) a first reinforcing support (58a2) that extends from the first curved neck portion; (ii) a second reinforcing support (58a3) that extends from a side of the first curved neck portion that is opposite the side from which the first reinforcing support (58a2) extends; (iii) a third reinforcing support (58b2) that extends from a side of second curved neck portion; and (iv) a fourth reinforcing support (58b3) that extends from a side of the second curved neck portion that is opposite the side of the second curved neck portion from which the third reinforcing support (58b2) extends. a first guide portion extending from the first curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; a second guide portion extending from the second curved neck portion and comprising a fastener engaging member constructed and arranged to engage the fastener; (i) a first reinforcing support (58a2) that extends from the first curved neck portion; (ii) a second reinforcing support (58a3) that extends from a side of the first curved neck portion that is opposite the side from which the first reinforcing support (58a2) extends; (iii) a third reinforcing support (58b2) that extends from a side of second curved neck portion; and (iv) a fourth reinforcing support (58b3) that extends from a side of the second curved neck portion that is opposite the side of the second curved neck portion from which the third reinforcing support (58b2) extends. (i) a first reinforcing support (58a2) that extends from the first curved neck portion; (ii) a second reinforcing support (58a3) that extends from a side of the first curved neck portion that is opposite the side from which the first reinforcing support (58a2) extends; (iii) a third reinforcing support (58b2) that extends from a side of second curved neck portion; and (iv) a fourth reinforcing support (58b3) that extends from a side of the second curved neck portion that is opposite the side of the second curved neck portion from which the third reinforcing support (58b2) extends.