What's most likely happening when a bolt will not keep a crank arm tight on the spindle, despite being tightened to torque, is that the crank arm interface is damaged in some way. The splines on the crank arm can be ovalized or otherwise damaged if ridden when loose. If the arm is damaged, no matter how tight the bolt is torqued, it will not stay tight on the spindle. Re-torqueing the bolt will keep the arm on for a short amount of time, but eventually will critically damage the crank arm bolt. Best bet is to have the left hand arm replaced.
Articles in this section
- Will my road crank fit my MTB, or my MTB crank fit on my road/cross bike?
- My crank arm keeps falling off even after I re-install it to proper torque. What is going on?
- I’m not sure what bottom bracket type I have, but I have measurements from my frame. Can you tell me what works?
- Just got a new crank and it came with some spacers. How do I know where they go, and how do I install my new crankset?
- I have installed my GXP bottom bracket, but there is space between the spider and dive side bearing. Is this normal?
- My Omnium crank comes really close to my frame’s chainstay and/or the chain is not straight. Can I space the crank out using spacers to change the chain line?
- My crankset came with pedal washers. Do I really need to use them?
- I want to use a Direct Mount 1x chainring with my direct mount capable crankset. What offset chainring do I need?