Spearmin

The rear thru axle on my Bianchi Infinito CV Di2, which I spent a fortune on in March, keeps coming loose. The first time it happened the wheel slammed against the rear fork and nearly caused me to fall off the bike.
Today, the front axle came loose and the wheel came off and nearly caused me serious injury. On the way home, I spent one and half hours stopping and retightening the axle to stop the wheel falling off the bike again. When I tried to tighten the wheel, the wheel would hardly turn. When I loosened it off to let the wheel spin. the axle unwound itself.
To make matters worse, the back wheel was also loose when I got home.

Is this a common fault with thru axles, or am I just unlucky? I bought the bike from a shop 200 km away. I have phoned them and they say they have never heard of this problem.

cxwrench

Thru axles are dead simple. Unless there is a problem w/ the threads they don't come loose if properly tightened. And that is usually pretty damn tight.

mpetry912 

something is wrong - either the threads are stripped, you have the wrong thru axles, or something else.

please get this looked at by someone familiar with your bike. Front wheel coming off could get you seriously injured

/markp

HillRider

You do realize that thru axles have to be slipped into the unthreaded (non drive side) side of the dropout and threaded into the other (drive side) dropout. It is NOT just a slip fit and has to be tightened firmly. If you aren't doing this, you better find someone to show you how.

Spearmin

Yep, familiar with that. After the first near death experience, I made sure the axle was as tight as possible. It didn't help. Before every ride, I check both wheels to make sure there is no play/wobble. I did the same today. It didn't help.

ARider2

Thru axles often have a torque value specified. I would torque it to spec and then see if it continues to loosen.

alcjphil

Unless the thru axle falls out completely it doesn't seem possible that a wheel could fall out of the dropouts. The axle has to be removed from the frame in order to remove the wheel for a flat repair.
Maybe pictures of the axles would be helpful

jimc101

This really is an issue you need to be taking up with the shop you got it from, maybe get time to demonstrate how the system works, as what your saying doesn't make too much sense.

cxwrench

And you'd have to be major league oblivious to miss that happening.
ETA: Just had that customer in the store as I was posting this. Santa Cruz mtb, thru axle 1 full turn at least loose. 1 pivot loose. Rear shock mount loose. Bike will not shift, housing is totally pooched and the cable was frayed at the derailleur. Guy had absolutely no idea and it took me a couple of minutes to get him to understand what a cable and housing were.

alcjphil

I am curious if this bike has disc or rim brakes

Joearch

I have the same bike and have not had any issues with my thru axles. Not sure what you have going on but odd you have same issue on front and rear wheel. How could they be coming loose unless they were not installed correctly. Get your self and the bike to the shop.

Spearmin

Hi,
I would like to thank you all for your replies. Although some were not that useful, they were nonetheless appreciated.
The importer phoned me this morning to ask me to take the bike to the nearest dealer.
After inspection, it seems there was a fault with the axles. The bike is on its way to Italy!

hounslow

No bikes have thru axles and rim brakes. The brakes aren't the problem

alcjphil

I know that. I asked in case the bike had rim brakes and quick releases that the OP thought were thru axles

SoSmellyAir

Hope you get your bike back soon. It does not sound plausible that the bike has to be returned to Italy for a proper diagnosis.

Equinox

I had my Bianchi Infinito CV for a little over a year during which time it performed flawlessly. Suddenly this spring, I began having shifting problems that I couldn't figure out as an inexperienced rider. It turned out my riear thru-axle came loose to the extent that the stress of riding on the back wheel damaged the pawls. It was a quick and easy repair by my LBS, However, I noticed a funny sound again after riding about 50 miles, and the thru axle was beginning to loosen again. Now I'm concerned this is going to be a recurring problem.

Spearmin

I waited to hear back from Bianchi on my thru-axle problem for a while. In the end, they offered me a new frame or my money back. I took the money.
I hope your problem gets sorted out.

Ogsarg

One thing I didn't see in this thread is if the thru-axle was able to be torqued to spec. If the thread dims were off and it couldn't be torqued properly, the defect should have been obvious from the start. If it could be torqued to spec, I'm curious as to what kind of defect could cause it to come loose.

jccaclimber

Perhaps not related to this case, but defects under the head of fasteners can result in reaching torque, but coming loose after a few stress cycles. This is why castings are spot faced. A tilt in the surface will cause the same issue. Non parallel faces on the head side dropout would do this, though I’m not sure that’s the case here.

Ogsarg

Thanks. Had not come across that before but it makes sense.