Rear sprocket nuts loosening

[fatboy]

This seems to happen every few months despite me thoroughly cleaning the threads on the studs and using various types of locking compound.
I'm assuming that chain lube may be breaking down the locking compound ( I used Loctite 648 last time and it still fails. 648 is the stuff you need when doing the sprag clutch ).
New set of nuts ordered, any wisdoms on this appreciated

[GregD-UK]

Hi all,

I have nylock nuts on mine, all dandy

[mangocrazy]

Something isn't right there, Paul. For Loctite 648 to fail you either need a consistent temp of 200 deg C or a short term temp of 250 deg C. The only thing that I can see that would cause that would be a failed bearing in the sprocket carrier. That could provide the heat and the vibration to shake the nut loose. That's the very first thing I would check before trying anything else.

Nylocs are a good move, but the best nuts (IMHO) to use are Aerotight stiff nuts. Here come de blurb...

They are vibration resistant self-locking nuts (also known as aero-lock nuts or stiffnuts) with distinct advantages over other forms of self-locking nuts, for example:

The self-locking function of the vibration resistant Aerotight Nut is still effective after a number of applications, so it can be re-used many times

The Aerotight locking nut is all-metal, with no inserts, so can be used in temperatures of up to 300o C and is not affected by oil, making this a superior product and ideal for use in the food, agriculture, civil engineering, automotive, chemical and aerospace industries, amongst others

Whether it is tightened down or not the Aerotight Nut will stay in position, provided the locking element is engaged* and does not have to achieve recommended tightening torque to be effective

No additional parts or special tools needed to install or remove

You can get them here:

http://www.nutsandbolts.co.uk/metric-ae ... -nuts.html

[Falcopops]

I've had nylocks come loose on my sprocket carrier, but after about a thousand years.

[fatboy]

Thanks for the shed load of info Graham ! I did not for a second think of the carrier bearing. Doh !
Will get the wheel off at the weekend and scrutinize and report back.
On the plus side, the silver one sailed through it's mot today, not even an advisory !
He's finally got used to my SL Carbon cans

[fatboy]

The new sprocket nuts arrived today, look similar to the Aerotight nut but not so substantial, no nylon insert but two metal tangs where the stud will cut thread on thus locking, look single use but far superior to Nylocs.
May be useful to know the thread pitch on my Y plate is M10x1.25, it may be different on later models, I bought some Stainless sprocket nuts listed as 99/04 Falco which were the wrong pitch