The crankshaft can shift inside of the housing, along the direction of the white arrow. Also the pedal-crank without the cogs is able to wiggle on the shaft. In the third picture, the shaft is moved to its other end. How can this be fixed?
by ThomasDM373
3 Comments
Undo the pinch bolts on the crank arm.
Press the crank back onto the spindle (though depending how long you’ve ridden with it like this, the spindle and/or crank arm may be damaged and require full replacement)
Set preload with [the large crank bolt](https://www.slowtwitch.com/wp-content/uploads/2024/05/53607-largest_02_Preload_knob_install.jpg). Cranks shouldn’t wobble, but should spin smoothly.
Tighten the 2x pinch bolts alternating. Up to ~11-14Nm.
You probably lost your crank fixing bolt you’re gonna need that to do this properly. Get one of those from an LBS.
Loosen the two bolts on your non drive side crank arm. There’s typically a little safety plastic clip there as well, disengage that. The crank fixing bolt goes at the end of the crank spindle and tensions the non drive-side crank. Tighten the crank arm fixing bolt(you’re going to need specific tool for this) so that the two crank arms are snug against the face of the bottom bracket but not tight enough to drag. Once that’s done, tighten the two bolts on the non drive side crank arms to spec(12-14 Nm).
If you’re familiar with adjusting a modern stem and headset it’s the same principle.
NDS crank wiggling on shaft and the process gone so far may mean that splines in the crank are already way beyond repair. As in the joint is going to slip both directions in rotation under alternating riding torques even if clamp bolts are fully tightened, and this will undo the preload bolt again.
This style of crankset is perhaps best executed by Shimano, mostly because they (in their typical fashion) hold the patent for their implementation of the joint.