Thru axle coming loose

[AverageJoeMTB]

Anyone else had issues with their thru axle coming loose? I've tried correct torque settings and over torquing a little but 2-3 trails later and it's loose again. Getting frustrating.

The first time it could have been nasty.

I've got a feeling my rear wheel bearing might be at fault, there is play and I'm wondering if it's causing the axle to come loose through movement.

Either that or the wheel bearing has been damaged by the play.

Thoughts appreciated.

 

[steve_sordy]

I bumped into a guy on the trail yesterday, he had his bike upended. I asked if he had everything he needed and he said he needed help! His rear axle had come loose, had done it before too. But he couldn't get the axle back in. He was faffing a bit, so I said I'd dealt with them before and offered to help. I removed his rear wheel and the mech hanger was loose. It nests in the frame and was secured with a tiny torx screw. I tightened the screw and re-positioned the wheel. The axle went straight in first time (the loose mech hanger had been blocking it) and it tightened up just fine, but the QR lever was at a really odd angle. I reckon that shrubbery may have been catching on the lever and loosening the axle. I showed him how to adjust the lever (pull outwards and rotate) and away he went.
We rode together for a while and when we stopped briefly, he introduced me as his mechanic! .

 

[RocketMagnet]

That sounds really strange as I've not had mine come loose and I Torque it to the specified 10Nm, if you overtighten you can damage your wheel bearing or significantly reduce it's life (I know I've done it before). Probably not a good idea to thread lock the axel threads as you should use grease and you would just be compensating for a fault elsewhere imo so not an option if you were considering it in desperation...

Really surprised you weren't experiencing shifting issues as it loosened off?

Personally I'd check and loosen then re Torque all the linkage bolts to make sure there is no frame play causing it. Gary posted the Torque specs in the Vitus page think they are mainly 15Nm with the small Horst link ones at the back chain stay seat stay intersection being only 6Nm.. check the post first though to confirm the correct values.

 

[Gary]

Yes bearing play/hub endcap movement can cause a thru axle to loosen under normal riding forces. As can a loose mech hanger retaining nut.

My Lyrik (stealth) maxle came loose today... but it was a pretty huge crash that caused it so sort of fair enough that something gave out. cool story Bro I know... but bear with me...
Afterwards I commented to my mate that I though it really odd that thru axles no longer expand or are bolted (pinch bolts) at the threads end to lock them in place.
Pretty much every DH bike ever produced had it's thru axles (f&r) secured this way.
We're now riding the same terrain at similar speeds on these bikes. (well.. .I am anyway)

As for your solution. I'd sort out your rear hub bearings ASAP, make sure the mech hanger nut is tight and fit the thru axle to torque (or nicely tight ). Then if it still loosens I would use a small amount of blue threadlock on the threads.
it'll just mean when it comes to undoing it again you'll need to "shock" the allen key a little to free the threads to loosen it.

 

[AverageJoeMTB]

Cheers all. Its not the rear mech, I've checked it, as the original symptom mid trail, as guessed above, was shifting issues so went there first before the axle. I'll check frame bearings too as I haven't done that yet.

Was hesitant to add lock tight but some blue might not hurt at least if the wheel bearing doesn't fix it.

What's people's thoughts on the stock wheel bearings? Was thinking of swapping them out ofr hope pro 4 hubs. I find them easy to work on and decent wear rates for my riding.

Agree about locking thru axles my old 40s had it and I'm probably faster on my two trail bikes these days.

 

[Gary]

there's absolutely nothing special about Hope hubs or the bearings they use.
Just replace the Novatec bearings with good quality sealed bearings from a good source when required.

 

[AverageJoeMTB]

there's absolutely nothing special about Hope hubs or the bearings they use.
Just replace the Novatec bearings with good quality sealed bearings from a good source when required.

I know there is nothing special about them. I have two other wheel sets using pro 4 hubs. I just know what they wear like and have spares, freehubs etc already. Wasn't sure how they'd deal with the eBike though.

 

[njn]

Use Loctite 248 QuickStix.