I’ve always used grease or anti seize compound on thru-axles as the last thing you want is for one to stick. However, I went for a quick blast this afternoon and somehow my rear thru axle came loose and the back wheel jammed badly on a fairly swift downhill section. It took some finagling to get the wheel unlodged and reseated, I came home carefully and gave everything the once over, and think I’ve got away with just a badly bent rotor.

I have absolutely no idea how it came loose. I rode a few days ago without incident and the bike felt fine. Today my gears started jumping, fixed on the move with barrel adjuster, just to reoccur 5 mins later. This was clearly an indicator that things were coming loose – hindsight is wonderful! I have had the wheel off recently but have ridden 6+ hours since then so think if I’d left it loose I’d have found out sooner.

I’m now wondering if:
a. I didn’t torque it up enough and it’s taken 6 hours of riding to come loose
b. My wife is trying to kill me and loosened it last night
c. One of my kids has been spannering (he and a mate have recently started showing interest in bikes and tools)

Interested in thoughts – could this have worked itself loose and would you use thread lock on a thru axle?

I always apply a smidge of grease to the axle and thread, was it torqued correctly (generally 10-12N) ? Very unlikely the grease had any impact, most likely under torqued.

If you’ve always done it, and this is the first time it’s failed, then I’m going for one of your A, B, C scenarios. No reason why it would suddenly become the incorrect thing to do.

I put a slither of grease on them too.

Yeah, they definitely need a very thin coating of grease on the axle before installation, especially if you tend not to take the rear wheel off for long periods of time.

Always worth checking axles and linkage bolts every couple of rides. Blue thread lock any that you notice slowly coming loose.