WHEEL/SPROCKET KEEPS LOOSENING, I'M SO DONE
- Thread starter datboi
- Start date
All of emHow many fingers you got chiz
The 3 together is 2
I doubt the swinging arm is at fault. It'll be an issue with the hub/axle/sprocket carrier.
Unless the threads are visibly damaged (check the nuts as well as the studs/axle) Hugo could be on the money with excess grease preventing full metal-to-metal contact. Bike gets ridden, hub gets warm, grease melts away and leaves a slack thread. I've heard of that happening in other situations, not necessarily on bikes, if the wrong grease is used. Most engineering greases are sheer thinning, which means that under sheer stress (compression) they revert to liquid form so metal-to-metal contact is assured. Some greases like vaseline are not sheer thinning and would create this problem.
Worth disassembling, cleaning off all traces of grease, torquing up dry and riding it to see if it does it again. If it doesn't, that's your answer you're probably using wrong sort for grease.
Unless the threads are visibly damaged (check the nuts as well as the studs/axle) Hugo could be on the money with excess grease preventing full metal-to-metal contact. Bike gets ridden, hub gets warm, grease melts away and leaves a slack thread. I've heard of that happening in other situations, not necessarily on bikes, if the wrong grease is used. Most engineering greases are sheer thinning, which means that under sheer stress (compression) they revert to liquid form so metal-to-metal contact is assured. Some greases like vaseline are not sheer thinning and would create this problem.
Worth disassembling, cleaning off all traces of grease, torquing up dry and riding it to see if it does it again. If it doesn't, that's your answer you're probably using wrong sort for grease.
And there isn't a way to tell other than keep replacing everything hoping i replace the part thats broken?
The thread looks ok
Interesting, in using lm48 assembly paste which is industry standard.
UNlike grease it doesnt change consistency at high temp and is equal or superior than what Ducati recommends.
If i assemble dry dont i risk cold welding and making it near impossible to break off later?
Also, dry torque will be significantly lower than with assembly paste, so 156nm might end up like 90nm
At least this is what the theory says....
So y'all think i should try this?
Assemble that shit dry and send it? And hope i wont go nuts next time i have to break that fucker loose?
Mind you: the other day i torqued that shit up to 170 and went for a 5km ride and it moved... So if heat was the issue here it wasn't the case
When a bolt is lubricated - less torque is required to achieve bolt axial load or tension. Reduction of torques for lubricated vs. dry bolts are indicated in the table below.
Lubricated Bolts - Reduced Torque
[th]
Lubricant
[/th][th]Torque Reduction
(%)
[/th](%)
[td width="232px"]
Graphite
[/td][td width="232px"]50 - 55
[/td][td]
White Grease
[/td][td]35 - 45
[/td][td]
SAE 30 oil
[/td][td]35 - 45
[/td][td]
SAE 40 oil
[/td][td]30 - 40
[/td][td]
No lube
[/td][td]0
[/td]Example - Reduction of Torque when Bolt is Lubricated
The maximum tightening torque for a slightly lubricated 1" Grade 5 coarse bolt is 483 lbf ft. Dry bolt torque is approximately 30% higher - or 628 lbf ft.Tdry = (483 lbf ft) (1 + (30%) / (100%))
= 628 lbf ft
If the bolt is lubricated with SAE 30 oil - the torque compared to a dry bolt is reduced with approximately 40%.TSAE30 = (628 lbf ft) (1 - (40%) / (100%))
= 377 lbf ft
Note that if torque specified for a dry or slightly oiled bolt torque is applied to a lubricated bolt - the bolt may overload and break.Yep, that's what I meant to say—you phrased it way better!
The manual calls for 156 Nm with assembly paste. If you torque to 156 Nm dry, the nut will definitely be too loose and will back off over time.
P.S. Factory manuals always assume clean, un-oxidized threads. If a manual specifies 20 Nm, but your bolt has old threadlocker, oxidation, or debris on it, your wrench might click at 20 Nm when the actual clamping force is closer to 10 Nm.
That’s why it’s always best practice to thoroughly prep the surface by degreasing and cleaning the threads with a wire brush.
(Which i did!!) and that son of bitch still backs off
chrisw
Elite Member
I have a £20 note and a £50 note.The 3 together is 2
You can choose to receive £20 or £50 or £70.
How many choices do you have.
£20 + £50 + £70 please
I choose violence. And a cool seventy quid minimum plus maybe a watch, too.
None of those are problems.. whats ya point?
chrisw
Elite Member
The problem is I don’t have the £20 or £50 notes, have got 36p in coins though.
I am very familiar with this problem
Are you even a real chippy ?
On one hand?
Most of em have been Stiched up or back on at some point, qualified enough?