Non-drive side crank coming loose (square taper)

[WKNDWRRR]

Hi Hubbers. My non-drive side crank arm on my road bike works itself loose after less than 10 Kms. I have tightened the crank bolt properly and even tried loctite. It's a square taper spindle. Any ideas?

 

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[Phatman]

Tighten the bolt on the right side crank as well, then tighten the left side again. And use a long Allen key. I had the same problem on an old bike and the bike shop said the crank arm taper was worn, so I just overtightened both sides and it held.

[WKNDWRRR]

Tighten the bolt on the right side crank as well, then tighten the left side again. And use a long Allen key. I had the same problem on an old bike and the bike shop said the crank arm taper was worn, so I just overtightened both sides and it held.

Thanks , I'll try that. I also think it's the crank arm taper that's worn. I might have to replace it 

[cfcjim]

Best to replace it, very cheap: Cycle Teknix have very some inexpensive units.

[WKNDWRRR]

Best to replace it, very cheap: Cycle Teknix have very some inexpensive units.

Replace the crank arm only?

[cfcjim]

Replace the crank arm only?

Sorry, the bottom bracket. But thinking about it, the crank arm might be worn as well.

[cfcjim]

Ahh. I was being an idiot. It's far more likely the crank arm is worn - alloy crank arm vs steel spindle.

[David Marshall]

Check out the prices carefully before you buy a new crankset.  Some new ones come with BB while others don't.  Might be time to get an outboard BB and crank rather than a square taper.

[BaGearA]

Check out the prices carefully before you buy a new crankset.  Some new ones come with BB while others don't.  Might be time to get an outboard BB and crank rather than a square taper.

You can't go wrong with this option