RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

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mjr
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by mjr »

SA_SA_SA wrote:Would it be much work for sunrace to mod the old fashioned trigger 3 speed shifter to use easily available derailleur cable and then return to it as the standard 3 speed shifter?

(the only plus of my 3speed nimbus control is it can take derailleur cable)

I think if the manufacturer was doing it, it'd just need to be a bit thicker to cope with the wider bullet end, but would be the same otherwise.

But the correct cable is widely available from various suppliers (the spare on my shed wall says Oxford Products, £4 with outer) so why would they?
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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SA_SA_SA
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by SA_SA_SA »

mjr wrote:....I think if the manufacturer was doing it, it'd just need to be a bit thicker to cope with the wider bullet end, but would be the same otherwise.

But the correct cable is widely available from various suppliers (the spare on my shed wall says Oxford Products, £4 with outer) so why would they?

Because it simplifys carrying spares in a common (saddle)bag (ie one type not two) for those who have hub gears on some bikes only and in a pinch I suggest most cycle shops will have derailleur gear cables but only some would special SA ones...
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mjr
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by mjr »

SA_SA_SA wrote:
mjr wrote:....I think if the manufacturer was doing it, it'd just need to be a bit thicker to cope with the wider bullet end, but would be the same otherwise.

But the correct cable is widely available from various suppliers (the spare on my shed wall says Oxford Products, £4 with outer) so why would they?

Because it simplifys carrying spares in a common (saddle)bag (ie one type not two) for those who have hub gears on some bikes only and in a pinch I suggest most cycle shops will have derailleur gear cables but only some would special SA ones...

Cables are light and I'm surprised if most shops don't stock at least some of both types of gear cable, but I've been told fenland bike shops are unusual. After all, I think they stock three types of brake cable, maybe more if discs don't use the same.

It seems like double-ended gear cable would be as easy as double-ended brake cable where you cut off the unneeded one, but I don't think I've ever seen it.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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Brucey
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Brucey »

as it happens you can use a standard derailleur cable in some pattern trigger shifters made after a certain date. But be aware that there is more than one issue:

a) the nipple. This is the obvious one and it is the easiest to overcome; three minutes with a small file will sort it.
b) the cable itself. SA cables for trigger shifters are ~ 0.9mm dia and most derailleur cables are between 1.05 and 1.2mm dia, usually about 1.1mm. In most older trigger shifters the slightly fatter cable won't even fit in the slot in the shifter , not without rubbing. It also won't pass easily through the (special) ferrule near the trigger, in many cases.
c) the pinch bolt at the hub end. These are/were made to accept the skinnier cable only. Again a standard derailleur cable may not feed through the hole easily.

After a certain date SA started making various crappy plastic shifters and at that point they started making pinch bolts with slightly larger drillings which will accept a standard derailleur cable. In some cases the cable won't pass through the hole because of small burrs, in which case they can be removed with the point of a needle file.

I genuinely can't remember the last time I had a cable problem 'in the field'. Cables make themselves known by going draggy and/or they usually fray rather than 'just snap', and when they fray, they fray in a way that is obvious if you can be bothered to look. So my advice is to look.

If you insist on carrying a spare gear cable, and it might be specific to the bike, why not stuff it inside the seat pin or something?

cheers
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Brucey
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Brucey »

I just counted teeth on the gears inside RX-RD5;

81T ring gear, 18T P1, 45T S1, 29T P2, 33T S2 (where the ring gear is in permanent mesh with P1 and S1)

S1 + P1 + P1 = 81
S1 + P1 = 63
S2 + P2 = 62

(81 + 45)/81 = 1.55555 gear interval 1-3, 3-5

(81 + 33 x 18/29)81 = 1.25287 gear interval 3-4, 2-3

1.5555/1.25287 = 1.24158 gear interval 4-5, 1-2

1.55555^2 = 2.41975 total range 242%

Which is slightly at odds with their stated four equal intervals of +25%, and a total range of 243%. I suppose it is possible that I miscounted, but I checked several times.

cheers
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SA_SA_SA
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by SA_SA_SA »

Has Brucey ever thought of sending a description of his ideal twin cable, non-NIG LH push-rod five speed design to Sunrace SA so they can make it?

Or should he send the exact opposite to counteract Not-Invented-Here-Syndrome and cause them to build what he (thus we) wants because they have done the opposite of what he suggested?
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leeta
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by leeta »

Excuse newly registered me digging up old topic of it’s not the done thing!!

I’ve a couple of rx-rd5 bikes - pashley roadster - got this used with fair low use, and tuberider same again used but pretty much unused- new tyres, factory lubed etc.

Both hubs have the same issues/personality: riding in 3rd gear will eventually pull the shifter cable in / pull the shifter round to fifth gear.

I suspect the big sweep of shifter cable going from handlebar to clip on the down tube is somehow overcoming the detents inside the shifter, could this be right?


Given both bikes are quite new but actually have now been washed I might now be thinking they can be rusted up inside the shifter especially if they are dry and not stainless innards - Brucey your pic above was enlightening!! The shifters both feel the same on each bike, vague, backlash, stiff. Awful really for such a pretty looking shifter.

Mostly I’ve persevered with the roadster as I’ve had that a while- I’ve had people suggest fit chain tugs, check the cables are lubed and generously long, tighten the axle nuts. Tugs I got didn’t fit, I used the harder serrated cast anti rotation washers instead, bike keeps the chain tight now. Cable I actually shortened to cut out a damaged section of outer but the shifter (occurred while carrying the bike home in the car!) and lubed it.

Since I’ve now got the tuberider and the hub feels and behaves exactly the same, I’m at a loss and ready for more advice!!! :-)

(Tuberider has traditional hook style dropouts - not vertical or horizontal. The hub spirant doesn’t seem to have yellow dot adjustment markings for this orientation, not helpful!)
rogerzilla
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by rogerzilla »

I gave up on the Sunrace SA stuff. It's nicely finished and you can see they are trying to improve the design, but they just don't know what they're doing. So we get badly-sealed large ball races, a NIG design where the pawl plate rattles or gets bent, and the S3X which has worn sun-locking dogs after a couple of hundred miles.
Brucey
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Brucey »

the way SA have implemented rotary shifting is very clever but if there is the slightest drag in the extra bearing or worse yet, contact where there should be none,, a tendency to autoshift is the usual result. So that is what I'd look at first.

The shifter itself is rubbish for sure, but it is probably not to blame for this particular malady.
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Carlton green
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Carlton green »

rogerzilla wrote: 21 Jan 2024, 12:39pm I gave up on the Sunrace SA stuff. It's nicely finished and you can see they are trying to improve the design, but they just don't know what they're doing. So we get badly-sealed large ball races, a NIG design where the pawl plate rattles or gets bent, and the S3X which has worn sun-locking dogs after a couple of hundred miles.
That’s a rather depressing state of affairs. How does an AW convert negotiate that minefield? A case of only buying old stuff ‘till there isn’t any left to buy?
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
rogerzilla
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by rogerzilla »

Yes. Luckily there are still millions of good AWs out there, and spares are fairly easy. Replace the clutch, planet pinion pins, springs and ball bearings amd they're as good as new. The ball races are very, very rarely pitted as AWs are very well sealed. Only actual immersion will let water in.
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CJ
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by CJ »

bgnukem wrote: 19 Feb 2020, 5:42pmFor the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
Yes in my experience: Sachs/Sram 7-speed.
Chris Juden
One lady owner, never raced or jumped.
Brucey
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Brucey »

IMHO the Sachs/SRAM 7s hub has always been let down (badly) by the external parts. In fact I have never seen a broken hub that was broken on the inside, it has always been the crappy external parts which have failed. Since these are no longer made, LBSs near me have a thriving trade in replacing these hubs with something that you can get spares for, which is usually a shimano 7s or 8s gear.
However, I have found that it is possible to covert these hubs, using mostly modified SA parts, so that the RHS of the hub has a pull-chain, and the left side uses a pushrod and an external spring for the cable. This arrangement gives independent control of the 3s shifts (RHS) and the sun locking shifts (LHS). Most importantly it means that you don't have to rely on crappy parts you can't even get any more.
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Carlton green
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Carlton green »

CJ wrote: 22 Jan 2024, 6:23pm
bgnukem wrote: 19 Feb 2020, 5:42pmFor the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
Yes in my experience: Sachs/Sram 7-speed.
I used to have a five speed Sach hub and was very pleased with it, eventually spares became too difficult to find so I reluctantly ditched that hub gear and replaced it with an SA AW . The three speed SA isn’t as good as that five speed Sach but it works well enough and has a spare parts supply route, if it breaks then I or someone else will very likely be able to repair it.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
Brucey
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....

Post by Brucey »

FWIW I have recently figured out a good way of attaching more than one sprocket to almost any hub gear. This allows a hybrid gearing scheme to be more easily run For example, using two sprockets with a 7s hub gives you 14 gears for peanuts. A poor man's Rohloff? -Almost.....
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