Theories on CRACKED wheel nuts

[canamryder]

Yes, these are only theories on causes, not cures or answers. I came up with this theory from working in a QC dept. at a hydraulic manufacturing co. for 24 years.
I imagine the company that machine the nuts receive extruded (maybe 10-12' long) roughly shaped 12 point bar stock bundles from their vendor. There may have been a batch(s) that easily got through whatever QC inspection is required. Laminations and or "stringers" may have been present internally in the bar stock. This would be hard to catch, not every bar can be cut and visually checked. Where I worked we had a problem with this because the vendor forgot to cut off the 1st & last 4' of each extruded bar. Maybe this is where most "stringers" are. Now I'm wondering if the nuts start cracking in the thinnest cross section of the nut, because of a "stringer" in that location, PLUS torque wrenches certified at up +4% maybe some are higher. 221 ft lb already seems high but add 4% to that = 230 ft lb. Not all alum. is created equal.
My personal semi immediate (solution?)with added $ would be to torque to about 215 ft lbs. Then possibly add the Monster Nutz by Lamonster.
http://www.lamonstergarage.com/monster-nutz-can-am-ryker-wheel-caps-3pc-set-lamonster/

 

[Rob Rodriguez]

If its a material issue than the problem you talk about can be solved by the parts being inspected (both visually and scanned by imaging machine) for material defects after they are manufactured. I have to think the issue is small because someone on a FB Ryker group posted the 2020 ECO changes for the rykers and the nuts were not on the list. This means the 2020 nuts are the same as the 2019's.

 

[PMK]

Possibly simply being that they could be made from extrusion, the grain of the material would be parallel to the stub axle, and the threads themselves induce a load trying to explode or split the nut.

 

[KC61]

I have learned being in Telecommunications for over 40 years to think simple first. That usually saves me a lot of time. Particularly who touched the machine last. So with that being said I suspect it is nothing more than incompetent personnel.

 

[MDLNB]

Not very knowledgeable when it comes to engineering, but to me it sure seems weird that something like a hub nut would require 221lbs of torque. Just saying. I am not suggesting that the amount of torque would make a difference in stress, just that since we are on the subject, that it seems like a lot of torque for a wheel.