I stripped the threads on my axle... now what?

[beef_wellington]

First of all, season's greetings to all.
Secondly... oops! I am pretty sure I did it when first installing the wheel. It didn't seem too bad at the time, as the nut was on there pretty good and didn't loosen after riding. After a couple of months of daily riding (and constantly checking all my nuts/bolts), I finally noticed it became loose. Then when I tried to tighten it down again, it won't grab at all. I bought some 12mm replacement nuts to try and do the washer/spacer technique, using the good threads that are left. However, even the ends of the axle are not receiving the nuts well, so I don't think this fix will be an option.

Is it possible to replace an axle in a C'lyte 408F? Are there any other repair options? Should I scrap it and upgrade to a 5-series?

 

[rbelisle1]

your best bet might be a machinist. I dont know if your axle is hollow or solid, so suggesting a fix is a little hard.

If its solid, you might be able to retap the threads, one or two sizes smaller. This of course would make the flat smaller or even non existant.

you might want to think about having it turned down and a outer sleave put on, then thread that sleave... again only if its a solid axle.

You might be able to totally recreate the axle on a lathe, the mate the new axle with the rest of the motor.

Welding, the machining the axle might work...

just sort of thinking out loud....

bob in phx.

 

[John in CR]

I assume there is some thread, just not where you need it. What I did on mine was effectively make the axle 1" diameter with 18mm flats. My machinist buddy took 1" round stock and threaded the inside to match the old axle, cut the flats and threads on the outside. The result is sleeves that screw right onto the axle. You'd have to enlarge your dropouts to fit, but if at the same time you add 1/4" of steel to thicken each dropout, then you won't ever have to worry about torque arms. The larger diameter nuts have a lot more grip too. I did mine in July and the nuts are still exactly how I tightened them. I check occasionally, but they've never loosened.

John

 

[fechter]

I think replacing the axle would be very difficult. It would probably be cheaper to just get a new motor.

If there are enough threads left, I would suggest getting a threading die and chase the threads to clean them up, then find some extra thick nuts (lug nuts?) that will completely cover the remaining threads.

Another option is to use a torch and add some brazing to the damaged threads, then use the die to cut new ones in the brazing. Not as strong as steel, but if you have some original thread left it will be adequate. This is not a good idea on the side where the wires go.

 

[vanilla ice]

If its solid, you might be able to retap the threads, one or two sizes smaller. This of course would make the flat smaller or even non existant.

This could work easy enough if you only go smaller on a portion of the axle's length. Retain the original size for the inner axle where the drop out would go. No worries about the flats then.

 

[beef_wellington]

Thanks everyone for your feedback. I'm taking your suggestions to my very handy brother, who will get me back on the road in no time.

 

[itselectric]

The proper way to fix this problem is to get replacement axle. We just order some replacement parts, It is expected to arrive in 2 weeks. We have both front motor and rear motor axles for 4x motor.

The steps to fix this:
- open up the motor cover
- take the motor out
- place the motor onto a 1 tone press
- press out the axle
- press the new axle onto the motor

http://us.itselectric.ca/

 

[mi7d1]

Thanks to Dennis who notified me of this thread, I can also offer my response. I had an axle swap done on two of my motors. I had a 406 front wheel and a 408 rear wheel. I wanted a 406 rear wheel motor for my velomobile. After an email conformation with Justin to confirm they could be pressed out, an electrician at my work used a 50 ton hydraulic press to swap my axles. Justin said that they've pressed out the axles using a 20 ton press. One of my axles were bent in the process and a machinist at work made me a new one that is a custom length for my Cruzbike. Last I asked about three months ago, Justin at ebikes.ca had front wheel axles in stock. With a big enough press they come out like butter from the stator.

 

[electricridefl]

my rear axle nut seemed to strip out the first time i loosened it , and the threads on the axle were harmed too....I screwed a lugnut for a yamaha golf cart onto the axle, with a couple of washers....the threads aren't exactly the same, but this has been working for several years now...

 

[beef_wellington]

I went home to pick up my bike, as my brother can't sleep unless he has fixed (or broken) something each day... even on Christmas. Since I already took care of the breaking, I figured his efforts could only help. After a close inspection, he decided that some wide spacers and some Loktite would fix the problem. It seems to have done the trick. He claims that the axle on the stripped side had some non-threaded axle exposed, which didn't give me enough thread to properly tighten the nut. And that an extra washer or two in the beginning would have prevented this.

I'll keep a close eye on the fix, and see how it holds. It is good to know that replacement axles are available. At the slightest sign of failure, I am going to get a new axle. Thanks again for the help.

 

[mi7d1]

I picked up some nyloc M12x 1.25 locking nuts at Ace Hardware. Perhaps you could also find some coupler nuts. The coupler nuts being much longer than regular nuts would have much more thread to bite into. On my 406 motor one side of the axle is stripped. What I did, I'm in no way recommending but it was better than running with only one nut and my two torque arms holding the rear wheel on. What I did was to run a half inch die and cut newer threads over the old stripped ones. Then I used a half inch coupler nut and that grabbed all of the axle that was exposed and for the first time in a while I was able to tighten down the left side of my wheel. Just another idea if push comes to shove. I'm hopping that Justin will get some rear axles in soon. If not I'll have a new axle made for me again or I'll make them myself.

We have a new Tech Shop branch opening here in Portland well it's really going to be Beaverton, Oregon. http://portland.techshop.ws/ It's going to be the same as the one in Menlo Park, Ca. complete with laths and Milling machines. I have plans to learn and make me several spare axles for my motors. Here's a link to the Tech Shop in California. http://techshop.ws/ The membership is a little steep for me but if I can learn and then make a small batch I figure it would be worth it.

 

[dogman dan]

I have about 1700 miles on my motor since I stripped one side. Rethreading one side to SAE threads worked for me. SAE simply since that was what I had in the garage. I try like hell to never have to take the wheel off the forks now though.

 

[docnjoj]

Same as above for my P2a. Threaded stripped side to 3/8 and use torque arm on other correctly flatted side! Ran a few hundred miles with no probs uhtil the steel planet gears bearings failed. Now awaiting reconstrucyion after Bafang!
otherDoc

 

[beef_wellington]

I'm hopping that Justin will get some rear axles in soon.

As of yesterday they have rear axles in stock, but not fronts. Apparently Justin even returns emails at 3:30AM Christmas night.

I took a long ride today, and everything is still snug. But I may just convert it to a rear axle should anything show signs of loosening.

 

[mi7d1]

I'm hopping that Justin will get some rear axles in soon.

As of yesterday they have rear axles in stock, but not fronts. Apparently Justin even returns emails at 3:30AM Christmas night.

I took a long ride today, and everything is still snug. But I may just convert it to a rear axle should anything show signs of loosening.

Thanks for the news. I'm going to order one. I like my motors on the rear wheel. I'm more comfortable with the strength of the rear dropouts. The Cruzbike being a front wheel drive has the wheels reversed. On my early version I still have the 135mm nut over lock on the rear triangle. That's why I had the special custom made one for my Cruzbike. I needed a front wheel with a 135mm spacing. The downside to the rear motor is the wheel dishing required. I've gotten around that problem with an offset spoke flange hub. Now the wheel dish is very close to zero on my velomobile.

You can see the offset flange on the left rotor. Notice also the difference in spoke flange thickness. If you do a rear motor conversion, you're gong to need the side cover for the thread on freewheel. I have three motors so that wasn't a problem for me.

 

[beef_wellington]

Just to update something I mentioned previously... Justin says he has decided to order some 4-series front axles in his next C'lyte order, due in February.

 

[Affliction]

Rethreading the axle 1 size coarser is a quick and effective repair. Cut the threads to M12 X 1.50 thread pitch. This has worked on numerous stripped axles.
Other benefit of this size it is what is commonly used for automotive lug nuts! Just don't use the tapered end against the dropout as it will spread it.