Rear axle coming undone

[leocompositing]

I got my decoy elite delivered a few weeks ago. I’ve been in love with the bike but I’ve been having issues the rear axle.

The first couple of rides the rear axle came undone, in a really dangerous way in the middle of the trail. Tightened back and made my way back home. After much research I learned that people have similar issues with the DT Swiss rear axle and some even use locktite which sounds a bit strange to me. I’ve got a similar axle on my decoy Bronson and never had that issue so thought was a dummy axle. I decided then to buy a through axle which I could properly torque to the right spec. To my surprise today the through axle came undone once again in the middle of the trail right after a rock garden. It could’ve been disastrous.

I’ve got a spare hanger that I bought with the bike: do you recommend that I swap the hanger? Is it possible that the hub is damaged?

Thanks in advance!

 

[Mikerb]

Assuming you are referring to the through axle rather than the hub axle....first check that the hub axle has no play, then ensure the threads on the through axle are clean and the threads on the captive through axle nut are also clean. Lightly grease the shaft and threads of the through axle and then tighten to specified torque.

 

[leocompositing]

Assuming you are referring to the through axle rather than the hub axle....first check that the hub axle has no play, then ensure the threads on the through axle are clean and the threads on the captive through axle nut are also clean. Lightly grease the shaft and threads of the through axle and then tighten to specified torque.

When you say hub axle do you mean the quick release? I’ve had issues with both of them. I assume the thread on the captive must be the issue. Isn’t going to make even more loose if I apply grease to the thread? Should grease be applied only on the shaft?
Thanks

 

[steve_sordy]

The Novatec axle on my Focus is not QR but requires an Allen key. After the first time it came loose, after six months, I torqued it up to the max of the range printed on the end (12-14Nm). The second time it came loose, two months later, I used Loctite blue and torqued it up. It never came loose again and that is after another 16 months.

There is nothing wrong with using Loctite blue on bolts that you don't want vibrating loose. Especially those that you don't want to be too tight in the first place!

 

[leocompositing]

The Novatec axle on my Focus is not QR but requires an Allen key. After the first time it came loose, after six months, I torqued it up to the max of the range printed on the end (12-14Nm). The second time it came loose, two months later, I used Loctite blue and torqued it up. It never came loose again and that is after another 16 months.

There is nothing wrong with using Loctite blue on bolts that you don't want vibrating loose. Especially those that you don't want to be too tight in the first place!

What happens if one needs to carry the bike on the back of the car and needs to remove the wheel for transport? Every time will have to apply locktite? That’s madness

 

[steve_sordy]

What happens if one needs to carry the bike on the back of the car and needs to remove the wheel for transport? Every time will have to apply locktite? That’s madness

I agree, madness. But then there won't be too much time elapsed before you will be forced to check the axle tightness. My situation is slightly different, although I too carry the bike on the back of my car, I don't have to remove the rear wheel, so it can be months before I check the axle tightness*. I have never had a problem with a similar Novatec axle on the front wheel, just the rear.

Another explanation of course is that my torque wrench is poorly calibrated. (And yours maybe?)

*Note: For shame steve_sordy, I really ought to check every bolt every time before I go out! (But bollocks to that!)

 

[Mikerb]

When you say hub axle do you mean the quick release? I’ve had issues with both of them. I assume the thread on the captive must be the issue. Isn’t going to make even more loose if I apply grease to the thread? Should grease be applied only on the shaft?
Thanks

The hub axle connects the hub to the freewheel, and the through axle ( a the name suggests) goes through it to connect the wheel to the chainstays. The hub axle has adjuster nuts on both drive and non drive side to ensure it is snug against the hub bearings with no side to side play.
The through axle can be an allen key fixing or a QR/Level type. Either way the normal torque is c 15nm. You cannot get the torque correct on any bolt unless the bolt has minimal friction. So the shaft of the through axle is lightly greased to enable it to smoothly go through the hub axle, and the threads are also lightly greased to ensure the threads in the chainstay/hanger ( whichever is applicable) into which the through axle secures, also has minimal friction. The correct torque is important. There is no spring washer etc because the correct torque slightly compresses the distance between the chainstays and that torque is also determined by the material ( ally) and pitch of the securing nut and bolt thread. If you overtighten, the chainstays no longer provide that spring washer effect and you risk damaging the threads.