Hello! As you can see, my chainrings wobble from side to side. I tried tightening the arm as much as I can, but it doesn't fix it. The 3 chainrings are straight (I checked them individually on a flat surface). Could it be the bottom bracket or the crank arm? Or do I just need to tighten it even more? Thanks!
by toutestparfait
4 Comments
[deleted]
Oval chainrings? Regardless, that’s fine.
Any time all chainrings move the same direction to the same degree in unison, three things could individually cause that or simultaneously contribute to that.
1. The crank arm interface might not sit perpendicular to the spindle, as in the crank mounted crooked. This can happen if one applies lateral force to the crank when tightening the crank bolt.
2. The spindle is bent.
3. One of the crank’s chainring mounting arms is bent.
Edit to respond to other comments: while common, it is not to design, though in some cases runout won’t cause significant rub on a derailleur or dropping a chain, and if that’s your situation, feel free to ride it like that.
When did your kid bash into the crank arm while parking the car in the garage?