Author Topic: New chain bedding in noise?  (Read 3951 times)

Matt2matt2002

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New chain bedding in noise?
« on: April 01, 2023, 08:04:58 pm »
After 10 months ( 1500 miles / 2500 Km )  on a KMC X1, I measured today in excess of 0.75 - so fitted a KMC X1 EPT 3/32 chain from SJS - ( 99 links  ie short ). I think it must have been on offer 18+ months ago.

As it happened - it fitted fine with only a slight adjustment of the EBB.
Q1  While loosening and retightening the 2 grub bolts on the EBB, it shifted laterally. I eyeballed it back as best I could but wondered if there is a proper way to make sure the front ring and rear sprocket are in line so that the chain runs smoothly?
Which leads me to Q2..
There is now a noise from the front ring EBB area. Like the chain is rubbing against something. It's not my Chainglider.
I adjusted the lateral movement of the EBB several times for quick test rides before a 5 mile spin.
After the quick 5 mile spin the noise has reduced and is only noticeable when the chain is under strain / I'm pushing up hill.

I can't recall this happening on previous chain refits.
There was no noise on the old chain.
The front ring does not appear worn to any degree.
While walking the bike the pedals rotate.
There is quite a lot of slack in the chain. Certainly not tight. The 2 finger grip in the middle of the chain moves it together quite a bit.

Thoughts folks?


Best Matt

Never drink and drive. You may hit a bump  and spill your drink

Andre Jute

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Re: New chain bedding in noise?
« Reply #1 on: April 02, 2023, 12:23:05 am »
The chainwheel should be set to the Rohloff chainline, which is the distance from the centreline of the bike to the centre of the sprocket teeth. There are several different Rohloff chainlines depend on sprocket type and number of teeth; check the manual for your particular sprocket. If you can't find a chainline number for your Rohloff, work with 54mm, the most common. The tolerance is 1mm, which is real tight for amateur assemblers because the measurements are difficult to take consistently.

Okay, now forget the theory of the "centreline of the bike" because in practice it is impossible to work from there. Instead put a piece of masking tape all the way around the seat tube but not overlapping at the ends, to protect the paintwork. Now use vernier calipers to measure the thickness of the seat tube where the masking tape is fitted, including the two layers of the masking tape, and the thickness of your chainring. Add the two measures together and divide by two. Call this Result A. Now measure from the outside of the chainring to the far side of the seat tube; this is Result B which consists of a layer of masking tape, a seat tube, some air, and the width of the chainring. From B subtract A and this is Result C, which is the chainline.

If you don't have vernier calipers, a less accurate measurement than with vernier calipers can be taken with a simple ruler. Look up the seat tube diameter in your bike specifications. With the ruler up against the seat tube at its nearest approach to the chainring, measure to the centre of the chainring. Add half the seat tube diameter. The sum is the chainline.

Good luck.

PH

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Re: New chain bedding in noise?
« Reply #2 on: April 02, 2023, 08:19:23 am »
After 10 months ( 1500 miles / 2500 Km )  on a KMC X1, I measured today in excess of 0.75 - so fitted a KMC X1 EPT 3/32 chain from SJS - ( 99 links  ie short ). I think it must have been on offer 18+ months ago.

I don't know why you're having issues, the addition of a Chainglider takes it outside my experience.
I do know a solution - Put the old chain back on for at least another 5,000 miles!  There really is no need to be changing straight line drive chains at such a short distance, the "stretch" is irrelevant as all three components are wearing together.  I thought the purpose of the Chainglider was to prolong the life of a chain.  The KMC X1 on my Mercury, exposed to the elements, cleaned by wiping with a rag and re-oiling, is currently on 17,200 km and I'm expecting to get a good few more.

Matt2matt2002

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Re: New chain bedding in noise?
« Reply #3 on: April 02, 2023, 08:34:35 am »
Thanks Andre and PH.

Andre your hint,/ explanation is well beyond my limited technical understanding. But thank you.

PH: I only mentioned the chain glider in passing since some folks say it can rub a chain and cause a noise. I heard the noise before refitting the ' glider.
Re time / mileage. I believe the 0.75 stretch limit is mentioned here quite often as the time to change a chain?  Do you have a limit yourself? Should I stop bothering?

I suspect the noise is caused by the teeth of the front ring not sitting properly within the chain links. Hence my concern at the ' chain- line.

I'll take another look later today.

Many thanks folks.

Best. Matt
Never drink and drive. You may hit a bump  and spill your drink

PH

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Re: New chain bedding in noise?
« Reply #4 on: April 02, 2023, 08:52:39 am »
TRe time / mileage. I believe the 0.75 stretch limit is mentioned here quite often as the time to change a chain?  Do you have a limit yourself? Should I stop bothering?

Best. Matt
Yes, stop bothering, that's the Thorn advice, wear all three together and then replace chain and replace or flip the reversible sprocket and chainring.

It's the chain which wears the other components, as the chain elongates the teeth wear to match.  That is the reason the advice is different for a derailleur where:
1) It makes economical sense to sacrifice several chains to preserve the more expensive cassette and multiple chainrings.  If you religiously replace at .75 theoretically the other components with last forever! If you do the sums it's easy to see this doesn't make economical sense with a singe chainline.
2) The sprockets on a cassette wear at different rates, depending on which get most use, per tooth, so  the chain wear will not match them all.  On a single chainline, not just on a bicycle they're used in plenty of other mechanical applications, you can get the full life from the chain as it'll always match the teeth. 

Matt2matt2002

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Re: New chain bedding in noise?
« Reply #5 on: April 02, 2023, 09:54:27 am »
Thanks PH

So it what point do you yourself replace a chain and flip the ring/ sprockets?

Best  Matt
Never drink and drive. You may hit a bump  and spill your drink

geocycle

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Re: New chain bedding in noise?
« Reply #6 on: April 02, 2023, 10:34:26 am »
Sounds like you might need to flip the chain ring?  Ive just changed a chain and sprocket and decided not to rotate the chain ring this time. If Id had a noise like yours that would have been my cue. They will last several times longer than the sprocket of course.
 

JohnR

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Re: New chain bedding in noise?
« Reply #7 on: April 02, 2023, 11:09:59 am »
I wouldn't lose sleep over perfection in the chainline. When I asked Rohloff support about the chainring on my Birdy Rohloff having a chainline of 49mm they said no problem as far as the hub is concerned. Eyeball should be fine for ensuring that there are no obvious lateral bends in the chain which will increase the wear.

1500 miles does seem to be a short mileage before needing replacement, particularly inside a Chainglider. I'm using the KMC Z1 (narrow) chains which are availablein brown for change out of 6 so it's easier to replace than give a thorough clean.

The easiest way to diagnose the noise is by elimination. Does it go away if you remove the Chainglider? What happens if you add a little extra lube to the chain (perhaps it's slightly stiff)? What happens if you increase the tension? Finally, what happens if you reverse the chainring? I'm using a Bikepunx 42T stainless steel chainring (available from the 'bay) which I would hope will outlive me.

martinf

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Re: New chain bedding in noise?
« Reply #8 on: April 02, 2023, 11:59:17 am »
To line up the sprocket and chainring I use one of two methods:

1. Eyeball. From someway behind the rear wheel I visually check that the sprocket and chainring are in line. 
2. Builder's straight edge rule. I place this against the chainring and check that the sprocket is in line.

Both methods are easier when the chain is not fitted, but still work with the chain.

I used method 1 yesterday after taking up chain slack on one of the visitor bikes.

The eccentric moved sideways a bit during the adjustment and on the test ride I noticed a bit of noise from the Chainglider. So I took the Chainglider off, moved the eccentric about 2 mm to the right, to where it looked correctly aligned, put the Chainglider back on and did another test ride, on which the Chainglider was quiet.

Matt2matt2002

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Re: New chain bedding in noise?
« Reply #9 on: April 02, 2023, 01:37:10 pm »
Thanks folks.
I'll re check my stats on the chain.

Best Matt
Never drink and drive. You may hit a bump  and spill your drink

PH

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Re: New chain bedding in noise?
« Reply #10 on: April 02, 2023, 05:55:03 pm »
Thanks PH

So it what point do you yourself replace a chain and flip the ring/ sprockets?

Best  Matt
My chainring sprocket combinations allow for a full throw of the EBB on both my Thorns*, that is when I fit a new chain the BB is as far towards the rear as it'll go and the chain is still at a suitable tension. When it gets as far as possible the other way and needs adjusting the only way to further tension the chain is to remove a link.  Before doing so I'll have a good look at the sprocket to see how hooked the teeth are and decide whether to remove the link or replace the chain. 
That's a bit of a judgment call, if it's the autumn and I have no big rides planned, I might add the link and get at least the winter out of it.  If I have some big rides or a tour coming up, I might replace.  It also depends whether it's the first or second side on the sprocket, if you wear the tips away on the first side it'll reduce the wear you'll have when you flip it.
I don't think the point where I'd need to remove a link has ever been under 10,000 km, even with cheap chains. I've never run a chain to destruction, I've never broken a sprocket or worn one beyond use, I am if anything over cautious!

*This wasn't the case on my Raven, so that always had a link removed when it ran out of adjustment.  Neither is it the case with previous versions of a Mercury, which have a mini EBB, for this I used a half link.

EDIT - Steve's experience posted last year, including some photos of worn components.  I've never worn anything that far, though his bike has a harder life than mine
http://thorncyclesforum.co.uk/index.php?topic=14287.msg109316#msg109316

« Last Edit: April 02, 2023, 06:09:14 pm by PH »

Matt2matt2002

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Re: New chain bedding in noise?
« Reply #11 on: April 02, 2023, 06:27:04 pm »
Thanks folks

I took a look at my stats again and think I made an error in my records
The chain was 21 months old and 5,500 miles - not a great deal I admit. Plus my bike was off the road for 4 months with zero miles .

Re the Chainglider- its not a factor in the noise issue. I only mentioned it since some folks think it can rub and cause a noise. The noise is there with the 'glider off.

It's not a tension issue since there is plenty of 'slack' in the chain.

I have move the EBB laterally slightly a few times and I pretty sure its eyeballed / lined up fine.

I think it's an old on new noise.
A 15 mile spin just now - and the noise is reducing. None at low / no strain on the chain. A lot less when pushing on the cranks.

I could reverse the front ring but it's not hooked or worn to any degree. So I think I'll run wit the issue and hope things bed in.

PH - thanks for your thoughts. So you have no need of a chain gauge to see the wear?

And thanks to everyone else who has contributed.

Never drink and drive. You may hit a bump  and spill your drink

PH

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Re: New chain bedding in noise?
« Reply #12 on: April 02, 2023, 07:22:33 pm »
PH - thanks for your thoughts. So you have no need of a chain gauge to see the wear?
No,I used to measure religiously when I've had good quality derailleur bikes, though used a nail and a steel rule rather than a gauge. Never done so on any single speed or IGH, not too fussed on my E-bike which is the last of my derailleurs and is probably going hub gear when it's out of warranty in a few months.

Your noise might just be that there's a little more wear on the sprocket and/or chainring than a new chain can perfectly mesh with. If you haven't yet flipped them, or have spares handy, it would be worth swapping to check, nothing but time lost if that made no difference, you could just swap back. 


 

Matt2matt2002

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Re: New chain bedding in noise?
« Reply #13 on: April 03, 2023, 08:06:41 am »
Thanks PH

I have not yet flipped it. I also have a new front ring and rear sprocket to fit in the future.

I think I'll flip it this week. As you say, just an hour or so lost if no change and can a look ways go back to how it is now.

Cheers. Matt
Never drink and drive. You may hit a bump  and spill your drink

Matt2matt2002

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Re: New chain bedding in noise? UP-DATE
« Reply #14 on: April 20, 2023, 08:51:40 pm »
Update
I didn't flip the front ring but after seeing a SJS clip on Instagram that recommended using copper grease on the EBB, the noise had gone!

I don't watch a lot of Instagram but have SJS set as a fav.
The clip showed a very worn EBB and one that had been cut out following a failure.
The clip recommended the copper grease and rotating the EBB 360 as an annual preventative maintenance task.
I have used ordinary grease in the past; probably 2 years ago. I spent 4 on eBay for a wee tube and after unclipping the chain I was able to turn the EBB 360 and add a generous covering of grease.

The ride the next day was super smooth.

Thanks folks for all previous comments.

Best
Matt
Never drink and drive. You may hit a bump  and spill your drink