Noisy Sturmey Archer 3sp

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Brucey
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Re: Noisy Sturmey Archer 3sp

Postby Brucey » 6 Jun 2020, 11:37am

I shall have a think about it but I would suggest we 'confirm the diagnosis' before we 'cure the disease' as it were.

If the idea is correct the hub will rattle in second gear (over bumps) even when you are pedalling and it will rattle worse when you are freewheeling because #7 can move too. Again if the idea is correct then either there is something subtle that is different in the CS-RF3 vs a standard (NIG) three speed or a standard (NIG type) three speed would rattle just as badly in your case because the wheel is moving around differently in the back of a moulton. I'm almost tempted to build a standard 3s NIG hub into a wheel for my Moulton and give it a go.

If the rattle hypothesis is proven correct a provisional idea for a cure is that #7 has ribs internally but these are only actually used over a short length where the driver pawls bear against them. For the remaining length of #7 they could be removed (ground away) which might simply provide enough clearance to prevent rattles, or alternatively it might be possible to fit a (plastic?) sleeve in that length, so that it can still slide OK but if it does move sideways, it makes contact but less noise.

I suppose that it is also possible that the RH end of the sliding clutch (#25) rattles against the inside of the driver (#13) in which case a different approach is required. To discriminate between the two possible sources of noise it may be possible to add something temporarily (eg heavier grease?) to the RH end of #25 in a rattling hub, and then observe whether it still rattles or not. If the rattle is bad enough it may be possible to do some of these experiments (or by adding other kinds of damping temporarily?) by locking the toggle chain off in second gear and simply bouncing the wheel up and down, which would be much quicker and easier.

cheers
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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 11:59am

Down in the workshop.
Yes, WiFi works in outbuildings too!

No7 and No25 put together out of the hub so No25 is inside No7, and when I wiggle them about, the noise is the noise I hear in 2nd gear.
I recognised it instantly.

I'm going to TRY to assemble the hub without No25 but I'm not sure if I have the spacers to hold everything together.
Mick F. Cornwall

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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 12:07pm

Can't be done.

Without No25 in there, there's no drive.
No connection at all, so cassette carrier No13 just spins.

Going to knock it all on the head now.
Dog to walk, and stuff to do.
Back to this thread later this afternoon.
Mick F. Cornwall

Brucey
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Re: Noisy Sturmey Archer 3sp

Postby Brucey » 6 Jun 2020, 12:33pm

without #25 present, #13 should drive #7 normally, as it does in gear 2 normally. #25 only transmits drive in gear 3, it interferes with the pawls in #7 in gear 1, and does nothing useful (apart from rattle...?) in gear 2.

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fausto99
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Re: Noisy Sturmey Archer 3sp

Postby fausto99 » 6 Jun 2020, 1:54pm

An idea popped into my head :idea: The SA cones have integral dust cap cum labyrinth bits. Would it be possible to fit one or two O rings in there to slow up any lubricant leakage?

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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 2:27pm

Brucey wrote:without #25 present, #13 should drive #7 normally, as it does in gear 2 normally. #25 only transmits drive in gear 3, it interferes with the pawls in #7 in gear 1, and does nothing useful (apart from rattle...?) in gear 2.
Back in from a long walk.
Not going back to the workshop now, though could do later. No promises.

From what I saw, 25 and 13 are always in connection irrespective of gear. 13 and 25 together drive the hub. Without 25, there is no drive whatsoever. As I said, from what I saw.

Willing to check again, so not arguing as yet.

fausto99 wrote:An idea popped into my head :idea: The SA cones have integral dust cap cum labyrinth bits. Would it be possible to fit one or two O rings in there to slow up any lubricant leakage?
My sentiments entirely.

No13 doesn't seem to want to come apart in any way. 13 has No1 and No2 in there, so as they are spare parts, they must be removable but I can't see how. There is a set of roller bearings in the body of No13 too, but they're not mentioned as a spare part.

No13 doesn't have a dust cap, and if I overfill the hub with lube, that's where the majority of the outflow comes ......... all over the cassette and chain.

Unless I can get No1 and No2 out, I wouldn't be able to get a seal in.
Mick F. Cornwall

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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 2:46pm

PS to both my points above.

No13 has pawls, so it must drive the internal ratchet of No7 irrespective of No25. I'll check on this later perhaps.

No13 has No1 and No2 in there and they are supposedly the same No1 and No2 as the LH end.
The bearings are the same, but the retaining rings are different.

LH end No1 is a washer with a groove that No19 mates with to form a labyrinth seal.
At the No13 end, No2 bearings are the same, but No1 is a flat disk of a washer plus I see no way of extracting it either levering outwards or pushing from the inside.
Mick F. Cornwall

Brucey
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Re: Noisy Sturmey Archer 3sp

Postby Brucey » 6 Jun 2020, 3:10pm

Mick F wrote:
Brucey wrote:without #25 present, #13 should drive #7 normally, as it does in gear 2 normally. #25 only transmits drive in gear 3, it interferes with the pawls in #7 in gear 1, and does nothing useful (apart from rattle...?) in gear 2.


From what I saw, 25 and 13 are always in connection irrespective of gear.


yes

13 and 25 together drive the hub.


yes

Without 25, there is no drive whatsoever
.

no; #25 only drives in gear 3. #13 drives #7 in gears 1 & 2

Willing to check again, so not arguing as yet.


please do so. I can only repeat what I wrote before.

fausto99 wrote:An idea popped into my head :idea: The SA cones have integral dust cap cum labyrinth bits. Would it be possible to fit one or two O rings in there to slow up any lubricant leakage?


excess lube mostly comes out round the ring bearing, rather than the cones. Sheldon Brown has a scheme for making something closer to contact seals for the cones using RTV, but I've never tried it on the ring bearing; I'm not sure it will be any good for that.

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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 3:16pm

Well ................

I nipped out to the workshop and brought back all the bits into the livingroom.
Having a beer!

Yes, without No25 and all the bits for gear changing, the hub sits in 2nd gear. That is, the cassette carrier No13 does the same rotation than No4 ....... the pawls of which engage with the hub shell.

Not fitted it back in the shell though, but it feels as if I'm right.
Nothing in the mechanism but the main shaft No2, No4, No7, No11 and No12, and No13.
No14 won't come off No13 as it's stuck.

IMG_0231.jpg


As for the "seals" here's a couple of shots to illustrate the differences side-to-side.
IMG_0228.jpg
IMG_0229.jpg
Mick F. Cornwall

Brucey
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Re: Noisy Sturmey Archer 3sp

Postby Brucey » 6 Jun 2020, 3:21pm

it should be second gear not first.

#25 pushes the high gear pawls (in #7) back in first gear. Without #25 fitted, you won't get gear1 unless you have somehow managed to stop the high gear pawls from working.

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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 3:31pm

PS:
Brucey and me crossed in the post. :D

The ring bearing, I suppose you mean No12 ....... the bearing that the cassette carrier has against the ball ring No11.
It would need a seal somewhere behind the dust cap No14.
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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 3:33pm

Brucey wrote:it should be second gear not first.

Sorry, I checked properly .......... immediately after I posted, and then edited. :oops:

Indeed it is in 2nd.
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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 4:59pm

Right .............

Had a think and a fiddle, and another beer ............

The hub will be assembled tomorrow morning and inserted into the wheel.
I will lubricate it with basic bog-standard general-purpose grease ....... enough to allow a ride of maybe ten miles. I'll test it out on Monday morning.

The hub is ready to assemble into the hub, and it will be minus:

Toggle chain and toggle No22 and No21 as well as 23 to 28 inclusive as they are all needed for 1st and 3rd gears.
It will be unable to get out of 2nd gear = direct drive.

If the hub is nice and quiet even though in 2nd gear, we will understand what it is that rattles my brains out.

Stand by for Monday. :D
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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 6 Jun 2020, 5:08pm

Bits not going into the hub.

IMG_0232.jpg
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Mick F
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Re: Noisy Sturmey Archer 3sp

Postby Mick F » 7 Jun 2020, 6:44am

Good morning.
Having a cuppa after waking up with another idea.

Having thought about this a lot, it seems pointless assembling the hub with the "missing bits" as it's 100% guaranteed to be quiet.
It blindingly obvious that it's clutch 25 that is rattling.

No7 has splines that engage with cassette carrier pawls. The trouble is, these splines go most of the way down No7, so clutch 25 wide bit is rattling against these splines. Added to which, clutch 25 is a loose-ish fit on the main shaft. Therefore, it's rattling in two ways but I'm not sure which is the main culprit.

I doubt there's anything anyone can do about the fit on the shaft, but the spline-length in No7 could be reduced so clutch 25 isn't rattling against them in 2nd gear.

Brucey has already suggested this of course.

--------------------------------------------------------

I have a cable-pull per click record of my bar-end shifter.

It's 25mm of total pull for the 18 clicks. Setting the yellow mark on the toggle chain so the bar-end is in mid position shows that 3rd gear (when the cable isn't floppy but not pulled) is at click4.
2nd gear engages at click7 but the yellow mark isn't correct until click10
1st gear engages at click13 but the cable isn't taut until click17

25mm for 18 clicks is nigh-on 1.4mm per click.
Therefore, with cable not pulling and in 3rd gear, clutch 25 lifts 6 clicks (click4 to click10) to get to yellow mark 2nd gear = 8.4mm of movement.

It's now a matter of assessing how much of the splines inside No7 to grind away a tad. The splines are only used at the top end by the cassette carrier. Pawl width is 6mm and as you can see the marks where the pawls have been, they measure a max depth of 8mm inside No7 ie up to where the No7 pawls are fitted.

Splines below the pawls are superfluous and can only be there to make manufacturing easier.

Photo of No7 internal splines to show where cassette carrier pawls run.
Click a couple of times to zoom in.
IMG_0234.jpg


Photo of No7 internal splines from the other end below the pawls. There are 5mm of "excess" splines.
Click a couple of times to zoom in.
IMG_0235.jpg
Mick F. Cornwall