Many riders are upgrading to power meters or switching to a 1X chainring setup. Our JCOB short cranks are fully compatible with both, but there are a few details to check to ensure a precise fit.

Align the indexing nub

On the drive-side crank arm, there is a small raised indexing nub in the center bolt circle. This must line up with the matching notch on the power meter or chainring. Without alignment, the part will not seat correctly.

Light fit adjustments may be needed

If the chainring or power meter does not slide into place easily, lightly file the inner bolt circle for clearance. Use a small round file or Dremel tool to remove only the surface finish — this is a minimal adjustment and does not weaken the part.

Ensure a flush fit

Once installed, the chainring should press fully onto the crank arm with no visible gaps. If there is a high spot, remove the ring and re-file the contact point very lightly.

With these quick checks, your crank upgrade will seat properly and perform reliably without stress or wobble.