Rear Hub axle keeps coming loose

[SlowManiac]

I have a '14 Trek Fuel EX 9 with a 142x12 rear hub. The rear axle has somehow worked itself loose 3 or 4 times now. Any ideas on what can cause this, what I can check if something is wrong before I crash and die? Also how to prevent it.

I am pretty sure I am doing it up pretty tight, it's happened enough that I think something is wrong.

 

[silentbutdeadly]

Whilst I'm largely ignorant of 142x12 axle fixings...that'd be the QR on the thru-axle that's not holding against the squirm in the rear chassis. Try a different axle.

 

[Ackland]

If it's just one of the threaded 5mm allen bolt in jobs, put some loctite on the threads.

If it's a maxle, check the torque specs on the lever - from memory, you need a 2mm (or is it 2.5mm) allen key to tighten the little grommet and then the maxle lever should be firm enough that when you close it, it leaves a small imprint on your palm that quickly fades.

If it's an x-12, then the conical fastening isn't contacting correctly

 

[SlowManiac]

I think it's a Maxle type - threaded on one end with a QR type lever on the other.

Thing is I do it up pretty tight - I guess I try and do it up even tighter.

 

[T-Rex]

I think it's a Maxle type - threaded on one end with a QR type lever on the other.

Thing is I do it up pretty tight - I guess I try and do it up even tighter.

If its a Maxle I suggest you go really easy. We run the RS 150x12s Maxles in T-Rex Junior's DH bike, and had the same problem with them working loose. I managed to break one by over tightening it with the lever. A $75 mistake. The RS Maxle takes a 6mm Allen key in the non drive side, which can do it up tighter than the lever.

However, the only thing I found that really worked was loctite .

 

[Ackland]

Check the lever tightening mechanism that I mentioned above before you start trying to really wind it tight or you can damage the "tightening collar" notch (if it's a maxle it will have Rock Shox Logos)

 

[teK--]

I think it's a Maxle type - threaded on one end with a QR type lever on the other.

Thing is I do it up pretty tight - I guess I try and do it up even tighter.

You need to clean all grease off the througbolt threads and where it screws into the dropouts. Also clean off grease from mating surfaces at the lever side as well. You can have a little bit of grease on the axle itself where it sits inside the hub.

Failing that, use some loctite on the threads after you've cleaned thoroughly and leave overnight to cure.

 

[SlowManiac]

Thanks, seems that this type of axle does have a few problems with them working loose.

I had a look, it's a Bontrager (Trek house brand) axle.

The grease thing strikes a chord, it started happening after a bike service and the shop did grease the axles.

 

[The_Taurean]

I had this problem just recently. I've got a 12 x 142 quick release (I think it's a formula one?) It actually came completely undone and I lost the chip that sits in the frame that the axle screws into. I discovered that there's a tiny little grub screw that goes through the frame from underneath and locks that chip into the frame. Once I tightened that up the problem seemed to go away. I think it must have been the chip moving in the frame that slowly undid the axle.

 

[Minlak]

I had this problem just recently. I've got a 12 x 142 quick release (I think it's a formula one?) It actually came completely undone and I lost the chip that sits in the frame that the axle screws into. I discovered that there's a tiny little grub screw that goes through the frame from underneath and locks that chip into the frame. Once I tightened that up the problem seemed to go away. I think it must have been the chip moving in the frame that slowly undid the axle.

The Trek System is a bit different and you don't get the grub screw to hold it in place. You screw the thread into the frame with a 24mm nut type arrangement. It is a bit annoying as my Trek has the quick release further away from the frame than i would like and vertical I prefer it facing backwards.

 

[tomacropod]

make sure the abp nuts are done up tight, this presents like a loose hub on the treks.

- joel