Left crank arm worked itself loose on the ride home, was fine this morning. Tightened up enough to ride home but was loose again 2 miles later. Right is fine.

Have dried everything out and tightened it up as best I can. Am thinking a drop of Loctite to secure it. Will this work?

They’re not octalink are they ??

Which model if crank?

Usually it’s knackered splines. Loctite will work in the short term but long term it’s new crank arm time 🙁

What kind of cranks are they? If they’re square taper then the left hand crank is knackered. The first time it worked loose the harder BB axle deformed the crank slightly which means that you’ll never be able to get it to stay tight again.

The good news is that square taper left hand cranks are usually reasonably easy to get hold of…

If Ht2, the little black plastic thingy that holds the crank in the correct place on the spindle can break and may need replacing.

Not Octalink. Square taper, cheapo no-name crank arms. Time for a new crank set I guess. Thanks STW’ers.

Re: ht2 – if you’re relying on the little plastic hat thing to hold the crank arm on you’re doing it wrong.

Make shims from coke cans.It’ll keep em going for a while (about 4 years on the commuter so far!).

I’m sure that I or someone else on here could sort you out with a square taper crank arm. There’s 2 things you should check though – the length, centre to centre of the holes, and the angle of the square hole compared to the arm. Shimano and Suntour are 45 degrees off from each other, like so:

Happened to my Truvativ Isoflow left crank arm too, I used Araldite on mine, popped some on the square shaft then fitted the arm as normal. It doesn’t stick the arm on in a sense that its difficult to get off, ots not, it simply fills the areas of the crankarm that are causing the play.
I do this every time I need to remove the crank arm and it hasn’t let me down yet. 😉