Left crank suddenly coming loose - what to replace?

[Butterbean]

Thanks, so helpful - as you can tell I have no experience with any of this - I'm in the Northern Suburbs of CT

 

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What time you hoping to ride tomorrow?

 

If you can come through to Somerset West tonight, I can help you out, unfortunately morning time I'm in church tomorrow, so can only help if you're planning to ride later in the day.

 

Let me know if you want to meet up, send me a PM and Ill send my cell

[brucem76]

What time you hoping to ride tomorrow?

 

If you can come through to Somerset West tonight, I can help you out, unfortunately morning time I'm in church tomorrow, so can only help if you're planning to ride later in the day.

 

Let me know if you want to meet up, send me a PM and Ill send my cell

Thanks so much, PM'd

 

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[droo]

Whoever said you an take the preload cap out after tightening is talking through their noughthole. Once you've done up the pinch bolts there's no way you're moving it.

 

That little pin is a last ditch safety backup and does nothing if the pinch bolts are properly tightened - don't worry about it.

 

Try with a new preload cap, but my feeling  is that the spline is now most likely worn from when the crank has fallen off, so you're probably in for a new crankset...

[JXV]

Deleted

[JXV]

You should have an o ring, the little plate with a pin, two bolts with washers, the plastic pre-tensioner cap and the crank arm.

 

Download the exploded view (EV) diagram from si.shimano.com

 

It will show all the bits. Procedure:

1. Slide crank arm onto shaft with clamp bolts loose and pin plate pivoted up out of the way.

2. Pivot the pin/plate into the clamp slot, locating the pin in the small hole on crankshaft.

3. Hand tighten the pre-tension cap using the correct Shimano tool listed on the EV diagram. The required torque is very low and hand tightening is sufficient. You are basically just taking up slack.

4. Tighten the clamp bolts alternately in small imcrements to recommended torque (12 to 14 Nm iirc) and do not overtighten these.

 

If you overtighten the pre-tensioner cap the head will split off from the threaded part and fall out. The crank will gradually work loose....BTDT. Buy (or borrow)the plastic Shimano tool for fitting the cap when you buy your new cap.

[Headshot]

Whoever said you an take the preload cap out after tightening is talking through their noughthole. Once you've done up the pinch bolts there's no way you're moving it.

 

That little pin is a last ditch safety backup and does nothing if the pinch bolts are properly tightened - don't worry about it.

 

Try with a new preload cap, but my feeling  is that the spline is now most likely worn from when the crank has fallen off, so you're probably in for a new crankset...

Ya its a no brainer. Just look at every new bike in the bike shop - they all have the pre-load cap installed and as you say its impossible to remove once the bolts are tightened.

 

You still need to be careful though. A few weeks ago I had the crank off to service the lower pivots and was distracted while reassembling  - I forgot to tighten the bolts. Half way through the ride off a small drop, the left crank spun on the axle and stayed put parallel to the right crank.. I had to be rescued by my wife as I'd left my tools at home too. A double no-no!

 

All seems fine now though, so these things can take some abuse.

[brucem76]

Confirmed - got a new crank bolt and installed - pedal crank staying on again. Phew!

 

 

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[Odinson]

Didn't want to start a new thread just for one question.

 

Does anyone know whether you can by a SRAM GX non-drive side (left) crank arm separately? I think I bent mine, but don't want to buy a whole new crankset just because of it.

[BaGearA]

Didn't want to start a new thread just for one question.

 

Does anyone know whether you can by a SRAM GX non-drive side (left) crank arm separately? I think I bent mine, but don't want to buy a whole new crankset just because of it.

Look for someone who has bought A stages arm then you should just be able to take it over form them.

 

 

Place A wanted AD , Or check if there is thread about stages ( I don't train nearly focused enough to worry about power meters)

[droo]

Deleted cos didn't read the whole thread. Poephol.

 

  

[carbon29er]

Didn't want to start a new thread just for one question.

 

Does anyone know whether you can by a SRAM GX non-drive side (left) crank arm separately? I think I bent mine, but don't want to buy a whole new crankset just because of it.

All other cranks are available to purchase left side only, but not the newest stuff like GX and Eagle.