Crank Type Identification

Crank Type Identification


Hello, Calvin Jones here with Park Tool Company. In this video we’re going to focus on crank type
identification. We will then refer you to the applicable crank removal and installation
video if it exists in our collection. We’ll start with self-extracting type cranks. The self-extracting cranks have a crank puller
basically built into the crank. A retaining ring that has fittings for a tool is
threaded into the arm surrounding the crank bolt. There may be pin holes for
the retaining ring, or a hex hole. This retaining ring has a
10mm hex hole. Inside is an 8mm crank bolt. Don’t confuse a dust cap or
dust cover with the retaining ring. This one has no tool fittings. If you are in
doubt, simply unthread the crank bolt. In this case, it’s a dust cap. so if the crank has a retaining ring, go to this video. For crank removal and installation of self
extracting style cranks. We’ll now focus on the two piece crank systems
that have no self extracting system. The two piece crank consists of one
arm with the spindle permanently attached and then simply the other arm. In this system,
the right arm and spindle are permanently attached. The left arm is held on with this
compression slot and two pinch bolts. If this is the style of crank you have, see the video crank removal and installation for two piece
compression slotted cranks. Another two-piece crank option is the
Campagnolo Power-Torque. The right crank arm has the
spindle permanently attached. The left arm attaches to the spindle with the crank bolt. After the crank bolt is removed, We can see a splined spindle inside the arm.
The crank arm has no threads for a crank puller For Power-Torque, see the video Crank Removal
and Installation: Campagnolo Power Torque. Ultra-Torque is another option from Campagnolo.
There are two large holes in the left and the right arm. Our crank bolt is buried deep inside the right arm. For Ultra-Torque, see the video
Crank Removal and Installation: Ultra-Torque Campagnolo also has the Over-Torque system in the two-piece option. Both sides have a large hole. The left arm is pressed on with a separate tool
and the security ring holds the arm in place. Another two-piece crank system is the
S-Works crank from Specialized. The crank is serviced from the right side. The dust cap is removed to expose the crank bolt inside. A long Torx bit is placed through the hole to remove or tighten the crank bolt. We will now focus on the three piece style cranks. The three piece cranks consist of a left crank,
a right crank and a separate spindle that joins the two. Three piece systems will have a crank bolt on either arm. If you have crank bolts on either side, go this video: Crank Removal and Installation
for Three Piece Style Cranks. Now let’s have a deeper look at the different
style of three piece cranks, starting with this one. To know what type you have, remove the crank bolt. Inspect inside for the interface and the fit.
This is a square tapered spindle crank. In this three piece crank, after removing the bolt, we
can look inside and see it is a spline style crank. Ten splines make it the ISIS drive system. This three piece crank is the Shimano Octalink. After removing the bolt, a look inside reveals
a splined spindle with eight splines. Yet another three-piece crank is the
Power Spline system with a bolt on each arm. After removing the bolt, you can see the
spline system engaged inside the splined arm. Another three-piece system is the Hologram crank from Cannondale. Each crank is held on with a separate bolt. After removing the bolt, you can
see inside it’s a splined spindle. While it is still around, the cottered crank is a three piece crank system that was popular before the 1980s. steel arms are held to a spindle with a
pressed pin. A nut keeps the pin in place. The BMX or freestyle cranks come in many different configurations. This is just one of many. One piece crank systems are just that: a single piece of steel is bent to form both arms and the spindle. The crank is then fitted through a large frame shell. A nut on the left side holds the bearing and the crank in place. for one piece cranks see, the video
Crank Removal and Installation: One Piece. As you can see, there are many different
types of cranks out there, and the list will only continue to grow with time. We hope this video has been useful and thanks for watching.