Had a particularly stubborn front sprocket nut the other day, wouldn't budge with the rear brake - breaker bar combination.

Tried giving it 5min of blowtorch heat, didn't help.

Then, even with my pal putting his full weight on the rear brake pedal (some brake fluid even leaked out at the rear banjo bolt), the rear wheel would still eventually move. Put the motorcycle on the ground, same thing, wheel would slip on pavement.

Finally, solved it by putting the transmission into 1st (obviously a poor idea).

This got me thinking: assuming all else fails (impact wrench, etc) how bad is it to put this much torque through the transmission? Doesn't clutchless shifting at high speeds put at least as much torque into it? Is it a 'not even once', or more of a 'don't do it too often' kinda deal?

The alternatives were not too great either: putting a bar to jam the wheel/swingarm could deform the wheel, and some say that blowtorching the axle/nut is a no-no.

What do you guys think?

  • Did you use the brake and put it in gear? If so, there'd only be a little added torque to the transmission, as the brake would be doing most of the work. I don't think putting it into gear would cause your tranny any issues. – Pᴀᴜʟsᴛᴇʀ2 Jun 26 '20 at 12:10
  • Stitch drill and split the nut or get a nut splitter. – Solar Mike Jun 26 '20 at 12:44
  • 1
    Make sure it is not left hand threaded. – Moab Jun 26 '20 at 21:43

If that much torque has been applied to tighten it then you’d think it would be ok to use the same amount to loosen it. Have you access to a compressed-air impact wrench? I’ve found those to be effective, and using the inertia of the output shaft reduces the force on the rest of the gearbox. Improvising some kind of strap wrench using the chain would be another thing to try


Not a complete answer, but found some discussion here on the subject with mixed opinion:


Including this video with an interesting trick of blocking the chain:


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