Rear end of bike making clicking sound - I need help diagnosing what may be causing it

[MudLark]

38 minutes ago, ChrisF said:

OFF TOPIC ... sort off ....

 

Couple of years back we bought a new 4x4, and a few weeks later we did our first trip in it.  It hade barely a 1 000 km on the clock when it developed the most annoying rattle in the cab ...

 

Is it in the dashboard ?

 

Is it in the centre console ?

 

everything gets moved and checked ... towards the end of the weekend this infernal rattle had me at wits end, and ready to skin the dealer on Monday .....

 

And then the light bulb moment .... I had removed the lighter to plug in the GPS power point ..... the lighter was rattling on the tray.

And then ethre was me with a metal water bottle rolling around inside and I was convinced that there was a 'clunk' in the suspension which had me checking the radius arm bushes etc....

[Schnavel]

I sorted out a creak on my gravel bike last night.

Rear thru axle was tightened to spec, but taking it out, re-greasing and re-torqueing it, the noise has now gone away. Also redid the hanger bolt torque.

OP, if it occurs in only the top 3 large rings on the cassette, my money would be on one of 3 things:

1. Cassette isn't properly torqued
2. Freehub bearings are on their way out
3. The cassette pinning could be creaking - if possible, can you swap out cassette and see if the noise continues

[Chadvdw67]

1 hour ago, ChrisF said:

OFF TOPIC ... sort off ....

 

Couple of years back we bought a new 4x4, and a few weeks later we did our first trip in it.  It hade barely a 1 000 km on the clock when it developed the most annoying rattle in the cab ...

 

Is it in the dashboard ?

 

Is it in the centre console ?

 

everything gets moved and checked ... towards the end of the weekend this infernal rattle had me at wits end, and ready to skin the dealer on Monday .....

 

And then the light bulb moment .... I had removed the lighter to plug in the GPS power point ..... the lighter was rattling on the tray.

My van also has also had 2 VERY annoying rattles/squeaks, one I thought was coming from the dash board, checked the cubby hole, checked under the dash at the wiring to make sure nothing was flopping around, could not find it for 2 weeks, one day, picked up a friend to go riding, apologized for the rattle, 2 minutes later, he clipped my sun visor back into its clip, rattle gone 😂🤣😂 

 

The other has been bothering me for over 2 years, passenger door squeaking, gets worse when the weather is cold and humid, checked the door rubber, went away for a few days, so I spent MONTHS trying various things with the door rubber, silicone spray, taping up the painted area of the door that pushes against the door rubber bla bla bla, everything helped for a day or 2 and then it was back, then one day my Dad noticed that the door had a bit of movement when it was closed, suggested I adjust the retaining hook that door latch holds onto, did that, squeak went away, bliss, 2 weeks later it came back,  adjusted it again, no squeak, few days later back again, I have now wrapped the hook thingy with some masking tape, and it has been so quiet for at least a month, like driving a whole different car 😂🤣😂

[MudLark]

1 hour ago, Schnavel said:

I sorted out a creak on my gravel bike last night.

Rear thru axle was tightened to spec, but taking it out, re-greasing and re-torqueing it, the noise has now gone away. Also redid the hanger bolt torque.

OP, if it occurs in only the top 3 large rings on the cassette, my money would be on one of 3 things:

1. Cassette isn't properly torqued
2. Freehub bearings are on their way out
3. The cassette pinning could be creaking - if possible, can you swap out cassette and see if the noise continues

In my case, it's clearly a chain/cassette interface issue. Or as I say, was.

[rudi-h]

Didn't read through all the messages, but effectively bike maintenance comes down to tightening bolts.  There are a handful non-bolting tasks exist such as bleeding disc brakes, putting sealant in tyres and greasing a pivot, but the rest is literally all just about wielding an allen key.

The ONLY way to tighten a bolt properly, is with a torque wrench.  Anything else is guessing and second best.  That's why it boggles my mind that not a single bike shop that i've ever been to uses a torque wrench to fasten bolts.

It's simple.  If you use a torque wrench and the appropriate torque sequence for every joint, there WILL NOT be any creaks, rattles or **** coming loose.

So if you have a squeak or a creak.  Loosen the joint and re-fasten properly by lubricating the treads and using a torque wrench.  It will change your world.

[MudLark]

1 hour ago, rudi-h said:

Didn't read through all the messages, but effectively bike maintenance comes down to tightening bolts.  There are a handful non-bolting tasks exist such as bleeding disc brakes, putting sealant in tyres and greasing a pivot, but the rest is literally all just about wielding an allen key.

The ONLY way to tighten a bolt properly, is with a torque wrench.  Anything else is guessing and second best.  That's why it boggles my mind that not a single bike shop that i've ever been to uses a torque wrench to fasten bolts.

It's simple.  If you use a torque wrench and the appropriate torque sequence for every joint, there WILL NOT be any creaks, rattles or **** coming loose.

So if you have a squeak or a creak.  Loosen the joint and re-fasten properly by lubricating the treads and using a torque wrench.  It will change your world.

Some threads are not meant to be lubricated. As I have it most torque specs are for a dry unlubricated thread. If that is right, your torque is perhaps as much as 40% off spec. 

See the Popular Mechanics article at this link and under the heading "To lubricate or not": https://www.popularmechanics.com/cars/how-to/a6613/torque-wrench-101-how-to-get-the-right-amount-of-force/

[rudi-h]

1 hour ago, MudLark said:

Some threads are not meant to be lubricated. As I have it most torque specs are for a dry unlubricated thread. If that is right, your torque is perhaps as much as 40% off spec. 

See the Popular Mechanics article at this link and under the heading "To lubricate or not": https://www.popularmechanics.com/cars/how-to/a6613/torque-wrench-101-how-to-get-the-right-amount-of-force/

Incorrect.  You are correct that there is a thing as dry torque values and wet torque values, it's important that you use the correct value.  That said, wet torque is ALWAYS better than dry torque and there is not a single joint on a bike where dry torqueing would apply.

The reason is two fold.  Firstly, with a dry-torqued joint, almost 90% of the torque applied is to overcome friction, and only 10% converts into tension.  Tension is what keeps a joint fastened, not friction, therefore a wet torqued joint always hold better and reduce the risk of over-stressing / stretching your bolt.

Second reason is that threads get damaged on a microscopic level on the surface under dry torque, further increasing the friction coefficient.  Thus, especially with bikes where we re-use and re-tighten fasteners many times, dry torqued joints tend to deteriorate over time, where wet torqued joints can be re-fastened 10's of times without any joint integrity loss.

In cases where suppliers / OEM's / technicians advise you differently, it's simply because they don't understand bolting theory and do as they've been told.  Even really reputable OEM's like CAT / Komatsu etc. incorrectly specify dry torque on some of their components.  We challenge them on this and after review they always revert to wet torque. 

[MudLark]

16 minutes ago, rudi-h said:

Incorrect.  You are correct that there is a thing as dry torque values and wet torque values, it's important that you use the correct value.  That said, wet torque is ALWAYS better than dry torque and there is not a single joint on a bike where dry torqueing would apply.

The reason is two fold.  Firstly, with a dry-torqued joint, almost 90% of the torque applied is to overcome friction, and only 10% converts into tension.  Tension is what keeps a joint fastened, not friction, therefore a wet torqued joint always hold better and reduce the risk of over-stressing / stretching your bolt.

Second reason is that threads get damaged on a microscopic level on the surface under dry torque, further increasing the friction coefficient.  Thus, especially with bikes where we re-use and re-tighten fasteners many times, dry torqued joints tend to deteriorate over time, where wet torqued joints can be re-fastened 10's of times without any joint integrity loss.

In cases where suppliers / OEM's / technicians advise you differently, it's simply because they don't understand bolting theory and do as they've been told.  Even really reputable OEM's like CAT / Komatsu etc. incorrectly specify dry torque on some of their components.  We challenge them on this and after review they always revert to wet torque. 

Okay Rudi. But my point is simply this. If a nut or bolt has been specced on a dry torque value of X and you lube it and then tighten it to X, the tension is way more than than what the original spec would have resulted in.  Arguably then you have overtightened the thing. I suppose it all depends upon exactly how the original torque spec is arrived at. Has the individual creating the spec correctly understood the principles etc? Anyway, I'm hardly an engineer, much less a fastener or materials engineer. Interested to read your further response.

[MudLark]

PS: Tension is a more accurate value if it can be measured. I think how a decent wheel builder measures spoke tension. And then I look at my torque wrench and think that it's actually a pretty crude tool in a way.

[rudi-h]

1 hour ago, MudLark said:

Okay Rudi. But my point is simply this. If a nut or bolt has been specced on a dry torque value of X and you lube it and then tighten it to X, the tension is way more than than what the original spec would have resulted in.  Arguably then you have overtightened the thing. I suppose it all depends upon exactly how the original torque spec is arrived at. Has the individual creating the spec correctly understood the principles etc? Anyway, I'm hardly an engineer, much less a fastener or materials engineer. Interested to read your further response.

You are correct that you will over-tension a bolt if you apply a dry-torque value to a lubricated bolt.  However, virtually all torque tables are based on wet torque values, so you generally do not run a risk of over-tightening when you lubricate threads.  Here is an example of a torque table that provides torque values for different friction coefficients.  Typically, a lubricated thread has a friction coefficient of ~0.1.

A new and clean dry bolt would typically correspond to a friction coefficient of 0.15, but if it's slightly rusted or galled (damaged after multiple re-use), it can be as high as 0.3.  If you google torque tables, a friction coefficient of 0.1 is typically assumed unless otherwise specified.

*Note, steel cap screws used on bikes are typically grade 8.8 fasteners, unless it's a special aluminium / stainless bolt that should have a factory spec.  You'd be good to use these values in yellow

On your question about the tension.  Its difficult to measure tension in bolts, hence torque is our best bet albeit somewhat crude and indirect.  There are ultrasonic tensiometers, but the reading is not an absolute value and some calibration needs to be applied, so it's not practical for 99.9% of joints.  This typically is only used for large fasteners on very critical bolted joints such as frame bolts on large Mining crushers etc.  Those devices are not small / compact enough for M4/M5/M6 bolts used on bicycles anyway.

 

 

[MudLark]

3 minutes ago, rudi-h said:

You are correct that you will over-tension a bolt if you apply a dry-torque value to a lubricated bolt.  However, virtually all torque tables are based on wet torque values, so you generally do not run a risk of over-tightening when you lubricate threads.  Here is an example of a torque table that provides torque values for different friction coefficients.  Typically, a lubricated thread has a friction coefficient of ~0.1.

A new and clean dry bolt would typically correspond to a friction coefficient of 0.15, but if it's slightly rusted or galled (damaged after multiple re-use), it can be as high as 0.3.  If you google torque tables, a friction coefficient of 0.1 is typically assumed unless otherwise specified.

*Note, steel cap screws used on bikes are typically grade 8.8 fasteners, unless it's a special aluminium / stainless bolt that should have a factory spec.  You'd be good to use these values in yellow

On your question about the tension.  Its difficult to measure tension in bolts, hence torque is our best bet albeit somewhat crude and indirect.  There are ultrasonic tensiometers, but the reading is not an absolute value and some calibration needs to be applied, so it's not practical for 99.9% of joints.  This typically is only used for large fasteners on very critical bolted joints such as frame bolts on large Mining crushers etc.  Those devices are not small / compact enough for M4/M5/M6 bolts used on bicycles anyway.

 

 

Thank you. I have just learned something new again! The information is golden!

Edited August 24, 2022 by MudLark

[droo]

8 hours ago, rudi-h said:

Didn't read through all the messages, but effectively bike maintenance comes down to tightening bolts.  There are a handful non-bolting tasks exist such as bleeding disc brakes, putting sealant in tyres and greasing a pivot, but the rest is literally all just about wielding an allen key.

The ONLY way to tighten a bolt properly, is with a torque wrench.  Anything else is guessing and second best.  That's why it boggles my mind that not a single bike shop that i've ever been to uses a torque wrench to fasten bolts.

It's simple.  If you use a torque wrench and the appropriate torque sequence for every joint, there WILL NOT be any creaks, rattles or **** coming loose.

So if you have a squeak or a creak.  Loosen the joint and re-fasten properly by lubricating the treads and using a torque wrench.  It will change your world.

 

4 hours ago, rudi-h said:

Incorrect.  You are correct that there is a thing as dry torque values and wet torque values, it's important that you use the correct value.  That said, wet torque is ALWAYS better than dry torque and there is not a single joint on a bike where dry torqueing would apply.

The reason is two fold.  Firstly, with a dry-torqued joint, almost 90% of the torque applied is to overcome friction, and only 10% converts into tension.  Tension is what keeps a joint fastened, not friction, therefore a wet torqued joint always hold better and reduce the risk of over-stressing / stretching your bolt.

Second reason is that threads get damaged on a microscopic level on the surface under dry torque, further increasing the friction coefficient.  Thus, especially with bikes where we re-use and re-tighten fasteners many times, dry torqued joints tend to deteriorate over time, where wet torqued joints can be re-fastened 10's of times without any joint integrity loss.

In cases where suppliers / OEM's / technicians advise you differently, it's simply because they don't understand bolting theory and do as they've been told.  Even really reputable OEM's like CAT / Komatsu etc. incorrectly specify dry torque on some of their components.  We challenge them on this and after review they always revert to wet torque. 

Also, Loctite. Aluminium fasteners being, as they are, prone to either stripping or galling at torque values high enough to achieve the right tension.

Weight weenie-ism makes for interesting problems.

Pretty interesting reading though, haven't looked at this sort of stuff in the 20 years since 2nd year engineering.

Back on topic though - OP - you can theorise all you want, but the only thing that'll work is taking the thing apart and putting it back together again. Properly. You'll find out pretty fast what's loose, worn, dry or broken. It's one of the things that makes bikes so great to work on - diagnosing stuff like this, 99.9% of the time, is just a matter of observation.

Not something you can do easily on a 4 stroke engine or a production line.

[MTBRIDER1234]

1 hour ago, droo said:

 

Also, Loctite. Aluminium fasteners being, as they are, prone to either stripping or galling at torque values high enough to achieve the right tension.

Weight weenie-ism makes for interesting problems.

Pretty interesting reading though, haven't looked at this sort of stuff in the 20 years since 2nd year engineering.

Back on topic though - OP - you can theorise all you want, but the only thing that'll work is taking the thing apart and putting it back together again. Properly. You'll find out pretty fast what's loose, worn, dry or broken. It's one of the things that makes bikes so great to work on - diagnosing stuff like this, 99.9% of the time, is just a matter of observation.

Not something you can do easily on a 4 stroke engine or a production line.

I have just taken the cassette off and the bearings out. I cleaned everything and applied grease/copper grease where needed. I think some fine dust worked it's way into the bearings and also potentially the cassette and xd driver interface. The noise seems to be gone, but I will truly be able to say conclusively after I give it a good thrash in tokai tomorrow.

Edited August 24, 2022 by MTBRIDER1234

[Stoffel76]

You did remember to remove the playing card?? 😝

But seriously, hope you found the problem!

[roodie]

sometimes the click is in your head , bump it really hard a few times and possibly the headache will numb any clicking noise 

and repeat ............

Edited August 25, 2022 by roodie

[MTBRIDER1234]

After a ride in tokai and a massive huck to flat off the wooden bridge at the beginning of dh4, for testing purposes of course, the clicking noise seems to be gone.

Whether it was the cassette or bearings (or perhaps the flat landing haha), I guess I will never know. Not that I care as long as the horrible noise is gone and my bike is running silent once again.

Only time will tell if the silence persists but I hope it does.

Thanks again for everyone's help and input on this thread and I really appreciate the willingness to help.