Mechanical explanation of the 987. Each arm's internal tension spring is accessible, replaceable, and adjustable. One end of the spring fits into a hole on the arm, the other end of the spring fits into a cadmium plated metal nut. The bottom of this nut is hex shaped with a 3.5mm rise, so a 13mm cone wrench can be used to adjust the spring tension. When mounted on the bike, turning it clockwise tightens the spring. A Black plastic shroud covers the spring assembly leaving just the hex bottom visible.
The brake arm revolves around a machined steel bushing inserted into a brass sleeve inside the brake arm. So the aluminum arm has a brass inner sleeve, which has a separate steel bushing that the mounting stud passes through. The brake pads are mounted on the rear of the arm.
The 987 relies on a traditional cable carrier arrangement. Each 987 comes with a 270mm long straddle cable that has two lead anchors on one end. A 7mm barrel shaped lead piece fits into the top of the left arm, the second lead anchor is to make a finger hold to quick release open the brake. The other end of the cable is bolted down, at the rear, to the top of the right arm. The cable fastening bolt is cadmium plated steel, with a 5mm hex fitting in its head. It's threaded has 6mm by 1mm pitched threads and is 10mm long with a 3.5 grams weight. The straddle wire is carried by a carrier stamped from aluminum plate. The Black carrier uses a «keyed» (fits in just one way) steel bolt with a hole through it. The brake cable inner wire passes through the hole and a Black aluminum nut tightens the bolt and two spacing washers to securely hold the inner wire.
The 987 comes with two Black steel washers and two Black steel mushroom head mounting bolts. These bolts have 6mm by 1mm threads, are 13mm long and weigh 5.5 grams. The steel washer covers the pivot axle beneath the mounting bolt. The brake
We found the 987 cantilever