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Discussion Starter · #1 ·
My 2019 Stumpjumper came with a 1x11 drivetrain with NX crankset. It seems every ride the crank arms are getting loose. I tighten the crank arm bolts, but it's only good for 10-15-ish miles before they start to get loose again. I bought some blue loc-tite, but due to the frequency I fear the crank arms just may be dunzo. A couple of questions:
1. On a bike with roughly 200 miles and only 5 months old, this seems like a warranty issue, right?
2. Any advice on keeping the NX crank arms on or are they toast? Will the loc-tite help or it is a lost cause?
3. Warranty aside, would an switch to a new setup be appropriate. I am on a budget so I am looking at the following setup. Shimano SLX or XT boost crankset, with a XT bottom bracket.
4. Would that be a stronger setup than the NX?
 

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If crank arms are ridden loose, the splines where they fasten to the spindle can get distorted such that the arm won't stay tight. This is almost certainly an assembly issue due to not properly installing the crank, not a problem with the cranks. It's not on SRAM but on whoever installed the cranks. If it was a shop, it's on them.
 

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Discussion Starter · #3 ·
KABOOM goes the crank arms. I tightened them to appropriate torque with a dab of blue loctite, then several miles out developed a wobble on the drive-side. The crank arm bolt sheared off.

My shop is throwing is discounting a set of GX Cranks with a DUB or BB30 BB.

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Loctite is not specified, necessary or desirable in this application. Grease should be used on the spline and fixing bolt. I would bet something went wrong with the installation process to cause this.
 
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