Epic Fail!

Before my epic fail I want to express my gratitude for this awesome forum. I'm really, really impressed by both the purpose as well as the technology coming around!!!

SO, Epic fail time. I've been hanging around and reading forums here for months and now I'm building a really nice ebike that I've been dreaming of for a while: X5303, rear, 6 packs worth of fatpackness, 72v please, Lyen controller... nothing complex, nothing crazy... In my previous life I worked on SCCA Cars, then went to Jim Russell racing school for a year before working on Porsches, then I went and built customs, motards and superbikes for a friends's AFM/AMA shop. I'm even Dynojet certified. So, i'm not exactly a nOOb, but I'm also a chubby college student now and not a dashing formula car driver and mechanic anymore, I just lurk around LEV Forums now. ehh. On to the epic fail.

I was installing the rear wheel tonight and, following electric riders instructions, buttered the bag out of the deralleur side threads. I have a snap-on torque wrench which is about as expensive as the rear wheel and 5303, with recent calibration, and I'm fairly certain- being that I was torquing in a three step sequence- 50, 55, 60, which was the figure electric rider states for the m14x1.5 thread. It seemed high, but so does the load on the setup. The left side came up to 55, but the right never made it over about 52.5, which in retrospect was probably more than tight enough ( for instance... mono bolted rear wheel on formula mazda race car? 110 Lbs. One bolt, 3/4" shank, 170 hp, 2600 lbs, 150+ mph...) but it was buttered by then anyhow so it needed to come off. I wondered if ER meant 60 Nm, but thats, what, like 45lbf? Oh retrospect. That sounds pretty reasonable, and would have clicked on the wrench on either side.

I'm pretty sure the nut failed before the threads, but then again I'm not entirely sure the pitch of these nuts ER included is as reliable as those on the really, really nice axle I just hogged. Honestly, after reading the torque plate murder thread, I was pretty impressed by the construction of the Clyte parts. I can't believe I did this. I'd include a pic, but really, I don't wanna look at it right now.

I'm going to try to chase the threads and then have my fabricator make me a double deep nut on his lathe, unless somebody knows where to find this (metric allthread is 14x2, thought of a coupling nut), which will (hopefully) reduce the individual load on each thread section and then lock that in place with low strength loctite, which shouldn't pose any more problem to get off than the 60 lb-ft bolt anyway, and gets around alignment issues.

Any other suggestions or experience which seems pertinent here? Whole thing scares me now until my fab dude- who was one of my teachers at mech school and former Penske indy crew- visits and blesses it. One thing which may come out of this is Massive Torque Plates for rear hardtail applications, if for nothing else than a reinforcement which would make the axle completely captive and possibly keyed.

thanks sphere!

Fails happen. Methods did the exact same thing the first time he tightened his Cylte hub into a frame.


As much as you don't want to see it, you gotta get a feel for how much of the damage occured to the axle thread vs the nut thread. I've seen some situations where the nuts are made out of some sort of china-butter-steel, and the axle pulls the threads right out of the nut and takes no real damage itself, but appears wrecked from the threads of the nut being stuck in the axle threads.

That torque sequence they recomend isn't smart. 50-55-60 only means a ~10% difference between the torque stages. The difference in the static and kenetic friction of the surfaces is higher than 10%. Meaning, if you correctly sweep the 50ft-lbs curve in 1-smooth motion (the only way a torque wrench can be accurate), the 55 and 60ft-lbs setting should just click with out the nut turning.

You gotta have at least the difference between static and kenetic friction Mu as the levels in a multi-stage torque sequence. That's why you see a flywheel bolt pattern say something like 22ft-lbs 1st stage, then 42ft-lbs final stage.

It's great to have another guy on here who enjoys wrenching on cars and racecars. There is a short supply of folks who are into racecars on this board, the more the merrier.

I seem to remember some finding that a lug nut had the right threads, and is a longer nut than normal. Not sure if that was x5 axles though, or smaller 408 axles. When I stripped a smaller axle on a WE motor, I was able to save it by rethreading the axle to a smaller size, in SAE. Then I was able to cross my fingers and tourqe it down, but not all that tight. Got away with it on a low power hub.

Ebikes-ca may still sell replacement axles. But some have had machine shops break the aluminum rotor doing the pressing. Do some hunting in the pics sections for x5 motor builds. Some have exellent examples of custom tourqe plates.

Awww shucks, I was hoping this was a hub spun dropouts fail so I could say something like:

"Hubs aren't meant for crazy torque."

Somebody here used a lugnut that was extra long.

Lugnut from an 85 Ford LTD fits my Fusin's axle, but it does not feel like a tight thread fit, so it may be a different ID than the OD of the axle. Don't know if it is metric or not.

After a good night sleep and some fine advice from various sources (my favorite? My friend who's dad has the aerospace machine shop who suggested simply fabbing one up and then having it hardened... I can only imagine the price tag) I'm going to try to chase the threads with a die (I hope my Mac set is good enough) and then try a deeper nut and a more conservative torque schedule, like 22-44-60. Also, i'm not going to run the lock washer, it's redundant and not really as effective as nylock, loctite or wire. I will replace the stock flat washer with an AN or other high grade piece, to minimize chance of distortion.

I'm going to try to find a lugnut with the m14 x1.5 thread thats real deep, at least 10 or so threads. Then, I'll have that lathed down so it's got a flat true face. I'm going to use loctite or safety wire (remember that stuff? Remember the .032 holes in your hands learning? Nothing looks cooler though, than well done wiring, imho...) to assure it's tension between flat tires (cross fingers). If my research is correct, that size lug isn't rare at all- it's used on chevy trucks!

Thanks again for the patience and help-

Sounds like a plan that will work fine to me

get a lug nut that fits your hub threads. just type 14x 1.5 or whatever the size is into amazon.com and they have tons of acorn lug nuts that could be a great fit. i am just saying this but I have not done it myself I just tighten the nuts that came with my hub with a snap on flat wrench and pray they don't let go!

Anyone know what type of thread the x5 uses. I've also partially stripped mine and would like to get a longer nut that can grip more of the working thread.

90% of the time the nuts strip out and the axle is fine.. ( not likely engineered this way, just the way it worked out at crystalyte parts availability lol.. )

Lowell reported using nuts from i think it was a porsche that were exact same thread pattern but can't find the thread with reference to it.

When the axle is long enough i like to use double nuts to lock them in against each other.

I counted the threads on the lug-nuts i use on my ebike and they were indeed 9 threads long. These lug-nuts are just the regular ones they sell at auto stores that are chromed, they look about one third longer than the regular ebike stuff, and cut deeper.

Did a search on ES;

According to drawings at http://ebike.ca/store Not all X5s use M14 nuts.
400 Series Front M12 x 1.25
400 Series Rear M12 x 1.25
400 Series Rear Disk M12 x 1.25
400 Series Project 19 DIA
5300 Series Front M14 x 1.5
5300 Series Rear M14 x 1.5
5300 Series Rear Disk M12 x 1.25
DC Front M14 x 1.5
DC Rear Disk M12 x 1.25

nice info thanks for doing the research

NorCalTuna,

Make the nuts and threads all but irrelevant by reinforcing the dropout and make it so that it clamps onto the flats of the axle. Here's one of my recent versions of this approach, which even leaves some room to adjust alignment or to tighten the chain.

WOW! There is a 10 pound solution to a 4 oz problem. Your solution is stronger than the torque arms on my 60,000 pound truck

I check at a wrecker today and found 14mm X 1.5 is a standard lug nut on many vehicles.

So, A bit of an update. The axle thread is super common- it's used on chevy trucks, porches, some vans and stuff...

Basically, there's no reason to run the nylock or the lock washer, they're a liability because of their cheepnis. The mr.lugnut plain conical lug, turned backwards, provides about 10 complete threads for the axle and a nice flush face. I also threw out the cheap washer and used a hardened piece from the local ace- about 7 bucks and now I have enough lugnuts to have spares when I lose these. Blue loctite- the weakest- rounds out the program. Lastly, a conservative torque program on my old reliable in-lb wrench up to the 720inlbs. No big snap on piece. The lugs look sick!

That clamping torque arm is very similar to what my fab guy and I came up with tonight...

I used a (mac?) repair tool on the threads to good effect, as well. Those nylocks should be binned. They're terrible.

stay tuned, Hopefully the name of the thread won't be applicable for too much longer!

were did you buy the mr.lugnut parts?

mr.electric;
My local auto wrecker has a "help your self" drum of them.

mr.electric said:

were did you buy the mr.lugnut parts?

Click to expand...

Kragen! I'm sure any ratty car parts store would have something like it. The trick is the non-shouldered conical face so you can run it backwards and still put the tool on it to torque it.

Hopefully anyone attempting to mount a hubmotor can figure out how to grind off the 45* cone

I want to get a locking lug nut to add security to my bike when it is locked to a pole.

FWIW my x5 is not 14x 1.5 or 12 x 1.25. Guess I'll try 12x. 1.5 tomorrow. Maybe I got a weird hub, Coulda been rethreaded once already since I bought it used. The nuts have been borderline for awhile, and I finally did strip em yesterday dangit.

Locking lug nuts could easily be grabbed with a vise grip on a bike. You could tack weld the axle to the frame.

mr.electric said:

I want to get a locking lug nut to add security to my bike when it is locked to a pole.

Click to expand...

Like dogman said, the security of a locking lug-nut comes from the 1" thick aluminum around it preventing vise-grips from grabbing it and turning it.

Well, I couldn't get any size lug nut to thread on my half stripped axles. They were 12x 1.25 but with the lugs it was hard to see if I was getting them started straight. Problem solved, as long as I keep the watts low, by using two new 12 x1.25 nuts instead of one. First I used a new nut like a die, tossed it, and then put on two new nuts. Good enough for 1000 watts, but if I ever get a real controller and battery for this motor, I'll have to just make some Costa Rico style dropouts and weld em onto the bike. Great design on that, John in CR.