New Yz250. I always clean the threads and nut with contact cleaner and torque to spec 92 ft lbs.
I've had the wheel on and off a few times for various things. Everytime I remove the axle nut a bunch of Metalic powder is present. I figure it was just a bit of galling and some of the zinc coating coming off.
Today I remove the axle nut and found a a chewed up thread. About half a thread( about mid nut, when torque ) was broken clean off.
I had thought about putting antisezie before but I known it will significantly affect torque spec and I don't want to overtighten and strip the nut or potentially have it work loose.
Has anybody else had this happen, it seems kind of bizzare since I did not cross thread anything, and did everything by the book.
Not happy, as a new axle and nut is 120$ canadian.
Looking for advice.
I grease the threads and never had an issue. I know it affects the clamping load so I reduce the torque ~20ft lbs, but I doubt it's actually necessary since you're not preloading the bearings. You're just making sure there's enough clamping force to keep the axle in place while riding. Valvoline moly fortified is my grease of choice for chassis bearings and threads.
Thanks, do you have a yz250 as well? I have also heard of the front aluminum axle nut stripping easily. The torque spec on that one is 77 ft lbs which is crazy high. What are you doing for the front?
Put the torque wrench away…
I have 2 yz450fx's, a TTR225, CBR600F2, DT125E, CRF50F clone, and have had a WR250F, KX250, WR400F, YZ250F, YZ250, XJ700X, V-Star 650, and TS50. All of them get or had grease on the threads with zero issues. That aluminum nut is fine for 80ft/lbs.
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I use a little excess grease from the axle all the way down onto the threads, too. It works just fine as an anti-seize for the length of time I commonly go between wheel removals. You don't need all 90 foot-pounds of torque, either.
I imagine this is a case wherein the Yamaha engineers thought to themselves, "overtightening and destroying the product is better than not enough torque causing the wheel to come off." I know from experience Japanese engineers think very carefully about that stuff. On items where rider safety is seriously affected (Wheels, brakes, suspension components,) they will err on the side of "that's not coming off."
After tightening gazillions of fasteners in a lifetime, I've now adopted the "manual, torque wrench guided method."
I basically use my torque wrench to monitor, but ALWAYS stop when I sense that's good/snug if the wrench hasn't beeped/clicked.
Many fasteners torque up as expected, no issues and it's nice to know they are to spec.
Others - like YZ250 2-stroke shock tower bolts do not. I always get about 1/2 way on those and say "Nope! No more."
I also strive to use the physically smallest torque wrench I can for the job so I have the least mechanical advantage which gives me better feel (vs. a 2-ft lever arm).
My brother nick named me “ Jonny over tighten” when we were younger…he was a much better mechanic than me, but I learned over the years…now I know for engine building mainly 4 strokes, an accurate torque wrench should be used….but for all my 2 stroke builds and my basic maintenance, I don’t use a torque wrench on anything, I don’t strip threads and nothing comes loose….I have seen guys use a torque wrench on rear axle nuts, so tight the bearings get killed….
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