My simple Front Sprocket Fix

[pointer2null]

Just looked at the wire fix again and I'm not sure that would even have an effect. The wire holds the nut to the sprocket right? If it's the sprocket thats forcing the nut over the threads then the wire will just keep the sprocket against the nut as the pair of them work their way off the shaft. (assuming the forces don't stretch/snap the wire).
One foccer used to put a spot weld on the sprocket and grind it off when it needed removing.

[Dead Eye]

I understand what you're saying. One of the reasons I'm not too owrried is on both the sprocket nuts I've had they both seem to undo one/two threads worth but then never seem to get any worse. It seem like when the pressure is reduced there isn't enough deformation in the thread to allow it to jump again.
In order not to tempt fate though, I will check it this Saturday.

This could be that over time, the vibrations and force on the first few threads (when the nut is tight) has caused them to wear. Once the pressure is off the nut and its moved on to some better quality threads, it stops moving... still not a good sign though

[packie]

Just looked at the wire fix again and I'm not sure that would even have an effect. The wire holds the nut to the sprocket right? If it's the sprocket thats forcing the nut over the threads then the wire will just keep the sprocket against the nut as the pair of them work their way off the shaft. (assuming the forces don't stretch/snap the wire).
One foccer used to put a spot weld on the sprocket and grind it off when it needed removing.

It's not the sprocket thats forcing the nut off. I lost mine nut and tab washer and was driving around for 1200 miles unaware of the fact with the sprocket still in place doing up to speed of 100mph. If the sprocket was on a forced outward journey, it would have come off too. The sprocket stayed on due to just a tiny little bit of rust which created a flimst bond. I was able to pull the sprocket off by hand easy enough when I changed my chain and sprockets. So there are no abnormal forces pushing outwards from the sprocket onto the nut.

One posters theory (which I attend to agree with) is that because the nut or shaft is isn't the right size and that there is some play between the two, the nut is vibrating to and fro and the threads are eventually getting damaged and stripping from all the rubbing with the shaft. And the shaft threads are getting damaged too. Your nut has just found a new set of decent threads on the shaft to latch onto. In time, it's possible that they will fail too and so on and so on.

That is why my wire job will do the trick. It's there to keep the nut in position. It can't work it's way outward anymore. On top of that, the wire that is on my sprocket takes a fair bit of force to cut through it with a sharp  pliers. So it is pretty tough enough to handle anything that might want to travel outwards even with a bit of excessive force.

Finally, as I stated elsewhere, I'm not advocating to have anyone to do it my way. I just posted this as a simple fix that I'm confident will work. Find another way like the spot weld or tapping the centre of the shaft to take a nut and large washer like "Unfazed" did. But for God's sake man, do something. Last year I have a horrendus fall at only 20mph and the damage to my body was appaling even with all my gear on. So just imagine if yer bike should lock up solid at 50-60mph and the consequences. Don't say you haven't been warned...not just by me, but by what your nut and shaft is doing at the moment.

[Dead Eye]

packie, are you not worried that the nut will pull the sprocket off now? Don't kill me, I'm just thinking aloud ^^

If it is the nut just vibrating off by itself, then nothing in theory will stop it from doing so bar extra resistance / grip to the output shaft. So, potentially, now that the nut is secured to the sprocket, as it comes lose, it will pull the sprocket with it, rather than the sprocket holding the nut in place... I'm not saying it will happen, its just something that crossed my mind - there may well be something I haven't considered which prevents this.

[pointer2null]

I can't imagine that the nut is simply vibrating off (the thread would need to be non existent at that point). I suspect that the socket is "bouncing" back and forth (left to right) and impacting the nut, forcing it off the drive shaft. The only reason the sprocket doesn't follow it immediately is that the chain holds it in line. Also with a high tension on the chain it will act to pull the front sprocket into line with the rear sprocket.  It would be interesting to see a breakdown of speed, sprocket alignment and engine mount condition (loose or soft mounts would allow the engine to rotate anti clockwise, when viewed from above, under load changing the alignment of the two sprockets) on bikes that have lost the sprocket.

[darrsi]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

[packie]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

.....a better idea.....don't use a nut at all!   

Seriously!!....while I was waiting for my nut to arrive I needed the bike because I couldn't be arsed to take my Bandit out of dry drock.. So what I did was, on the shaft I put a very very tightened Jubilee Clip that you use for hoses ect. I tell ya one thing, I should have just left it there and saved myself £11 on a nut. It was rock solid and a bas!a%d to get off when my nut did arrive. I rather have that than going around with a dodgy nut loosening every so often.

[stevierst]

Hell fire packie, you should be on the engineering design team with ideas like that. :D:D

Sent from my HTC One X using Tapatalk 2

[Fazerider]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

[darrsi]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

What's so funny? 

[Fazerider]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

What's so funny? 

Sorry, assumed you were joking.
PTFE, being the slipperiest substance on earth, is pretty much the opposite of threadlock.

[His Dudeness]

packie, are you not worried that the nut will pull the sprocket off now? Don't kill me, I'm just thinking aloud ^^

If it is the nut just vibrating off by itself, then nothing in theory will stop it from doing so bar extra resistance / grip to the output shaft. So, potentially, now that the nut is secured to the sprocket, as it comes lose, it will pull the sprocket with it, rather than the sprocket holding the nut in place... I'm not saying it will happen, its just something that crossed my mind - there may well be something I haven't considered which prevents this.

killed by a 5 page answer

[His Dudeness]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

What's so funny? 

Sorry, assumed you were joking.
PTFE, being the slipperiest substance on earth, is pretty much the opposite of threadlock.

wrong! banana skins are the slipperiest substance on earth

[Dead Eye]

Random idea, but what about using P.T.F.E. tape on the threads before tightening up the nut? 
You know the white stuff that plumbers use to waterproof pipe joints.
Surely that would take away the vibration, and fill any possible imperfections of the thread making the nut more difficult to move?

 

What's so funny? 

Sorry, assumed you were joking.
PTFE, being the slipperiest substance on earth, is pretty much the opposite of threadlock.

Unfortunately true and backed up by wiki (granted not the MOST accurate source, but still)

"PTFE has one of the lowest coefficients of friction against any solid."
http://en.wikipedia.org/wiki/PTFE

[darrsi]

It's not something that i use but just thought i was adding a possible idea to solve the issue.


But obviously i've made a huge mistake and must apologise unreservedly for sounding like a dumb foccer!   

[Dead Eye]

Haha, its ok, we've all done it before :P

[unfazed]

 Well it would definitely stop the sprocket leaking,