Problem with internal cabling to hub gears

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Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Problem with internal cabling to hub gears

Postby Brucey » 7 Apr 2018, 12:52pm

you can use a standard metal ferrule (on any housing) in a nexus cassette joint provided

a) it is the right size,
b) it is strong enough (some are very thin walled) and
c) it is bonded (or crimped) to the housing end

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

vandjq
Posts: 66
Joined: 16 May 2007, 11:30am

Re: Problem with internal cabling to hub gears

Postby vandjq » 7 Apr 2018, 12:53pm

Thanks Brucey :)

Brucey
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Re: Problem with internal cabling to hub gears

Postby Brucey » 7 Apr 2018, 1:13pm

in general terms an issue with most hub gears is that the adjustment needs to be better than it seems. By which I mean that you can test the gears all work on the workstand and it means almost nothing; in Nexus hubs it just means the correct pawl is lifted, but it doesn't tell you if it is lifted all the way. If it is not lifted all the way then the gear will slip under load.

In an N8 hub you can only check the adjustment is 'correct' in one gear. There are certain faults that mean that it looks OK in that gear but it isn't OK in other gears.

There is also the possibility that (for various reasons) the marks on the CJ do not coincide with the correct gear adjustment anyway. This is commonplace on older A11 hubs. In A8 and N8 hubs wear or bad manufacturing can mean that there is a systematic fault of some kind which means that either

a) the correct setting is a little bit away from that which the marks suggest or
b) there is a real problem in the axle unit that means that the sliding clutch shift is not properly synchronised with the pawl lifts. In such hubs it is possible to set the hub so that gear 5 is OK but most of the others are not, or vice-versa.

You can often establish a correction for a type a) problem by trial and error. A typical result is that the cable needs to be set 0.5 or 1mm tighter than the timing marks suggest.
When I overhaul such hubs I make sure that I have the axle and the CJ that is to be used on it and I check these things. You can make a new timing mark on the CJ to tell you the correct setting if you have a type a) problem.

However if there is a type b) synchronisation problem then whilst it is possible to reprofile (and therefore retime) the cam that works the sliding clutch, it is easier just to fit a replacement axle unit.

John S reports that upshifting to the timing marks produces a visibly different result than downshifting to the timing marks. Any hub that manifests this sort of behaviour cannot work properly and nine times out of ten (or more) the fault lies in the cable.

Roadster asked me to explain what I meant about the housing routing and how it can interfere with the position of the CJ reaction arm. I can't find better words than I used first time around to describe what I meant. Maybe someone else can have a go...

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Roadster
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Re: Problem with internal cabling to hub gears

Postby Roadster » 7 Apr 2018, 3:21pm

I have not asked you to explain how cable routing can interfere with the position of the CJ reaction arm - I didn't need to, because I already understood that from my own experience without your help. I actually asked you to explain what you meant by a cable stop being "in the wrong place", and it's unreasonable to expect someone else to do that for you.

In my earlier post, I said that moving the position of the axle in the dropouts should not alter the cable adjustment and you replied that in reality it does. You are confusing cable adjustment with cable installation which are two different matters. It's important to understand the difference between them when gear selection problems arise following re-tensioning of a drive chain or belt, because otherwise you can easily end up fiddling with the cable's adjustment when the real cause is disturbance to its installation.
Last edited by Roadster on 7 Apr 2018, 6:16pm, edited 1 time in total.

Brucey
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Re: Problem with internal cabling to hub gears

Postby Brucey » 7 Apr 2018, 5:51pm

a cable that looks fine and works fine can cause trouble once the wheel is moved. A cable stop can be in the wrong place because it can cause the cable housing to either pull or push on the CJ reaction arm and it can often do so differently if the wheel is moved. A full housing will often take 'a set' through every eyelet and will then (after the wheel is moved) try to return to its original position once the bike is ridden or the steering is turned a few times. This can cause the CJ reaction arm to start moving around. I have seen all these things several times.
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Roadster
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Re: Problem with internal cabling to hub gears

Postby Roadster » 8 Apr 2018, 1:35pm

Thank you, but that still has more to do with cable installation than with cable adjustment, and I'm still left wondering why you couldn't just say that in the first place instead of willfully misrepresenting my question. Perhaps you'd also care to enlighten us as to why you sarcastically invited others to explain, on your behalf, the answer to a question which I hadn't actually asked of you.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Problem with internal cabling to hub gears

Postby Brucey » 8 Apr 2018, 11:51pm

Roadster wrote:Thank you, but that still has more to do with cable installation than with cable adjustment, and I'm still left wondering why you couldn't just say that in the first place instead of willfully misrepresenting my question. Perhaps you'd also care to enlighten us as to why you sarcastically invited others to explain, on your behalf, the answer to a question which I hadn't actually asked of you.


You may have, but I didn't mention 'adjustment' or 'installation' , just that in some cases it can make the gears not work properly when you move the wheel, and the reasons why. Please read what I wrote more carefully and stop construing daft reasons and motivations for things that don't even exist. It is exceptionally tiresome and counterproductive.
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vandjq
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Re: Problem with internal cabling to hub gears

Postby vandjq » 9 Apr 2018, 12:22pm

On a more philosophical note, I am curious about how all those people in the Netherlands get on with their hub gears. I'm guessing that because it is so flat they manage with fewer gears. My commute is fairly flat, so I could probably manage with 3 gears and (possibly) avoid the bother I've had with 8. But do the Dutch use Shimano or manufacture their own IGH? Either way their bike shops must be very expert at fixing them. But how do we get access to their expertise? :?

Brucey
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Re: Problem with internal cabling to hub gears

Postby Brucey » 9 Apr 2018, 12:36pm

The Dutch have long been the biggest single market for SA hub gears. In fact Sun-Race bought out SA's assets at the behest (and with the financial assistance) of SA Europe when SA was wound up (disgracefully, blame greed and our stupid property market) in the UK.

Until recently Sachs (SRAM), SA and Shimano were all well-represented in the Dutch market. Now SRAM don't make hub gears any more. Perhaps surprisingly, there has never been a perceived need for IGHs with close(r) ratios in the Dutch market. SA and Nexus 3s gears are popular on basic models but the most commonplace gear with more than three speeds is the Nexus 7. The big growth sector in the Netherlands is presently e-bikes and that raises a whole load of new problems with transmissions; the chickens have yet to come home to roost on that one.

The Nexus 7 was designed with a near-unique sun locking design such that the gear was much less likely to slip than N8 even if the cable was bad. However they have recently changed to a design with a sun-locking arrangement that is more like N8 and I think the gear is less reliable (if cheaper to make perhaps) as a result.

The N7 gear is less efficient than N8 (premium) but is a pleasant gear to use.

cheers
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mjr
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Re: Problem with internal cabling to hub gears

Postby mjr » 9 Apr 2018, 12:46pm

vandjq wrote:But do the Dutch use Shimano or manufacture their own IGH?

On recent trips, it's looked like Shimano have most of the market, with some SRAM and SA. I think SA used to license the AW design under Raleigh (I think Puch or Steyr made some in Austria - there was probably a Dutch licensee) but I bet new owners SunRace don't.

vandjq wrote:Either way their bike shops must be very expert at fixing them. But how do we get access to their expertise? :?

Train, boat or long ride? Or you could just go somewhere in this country like Cambridge and visit one of the shops there like Bicycle Ambulance that publishes list prices for hub gear work... but three speed hubs seem a lot more obvious than higher-speed ones and even the youtube videos of complete reassembly don't seem superhuman.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

Brucey
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Re: Problem with internal cabling to hub gears

Postby Brucey » 9 Apr 2018, 1:42pm

At one time FIchtel und Sachs had a license to manufacture according to SA's patents. Plenty of Dutch bikes were fitted with (often manufacturer branded) hub gears that looked like SA ones, but the reason they looked like SA ones is because they were SA gears, from Nottingham. I do not think that they ever made hub gears in the Netherlands, not in any numbers.

SRAM have now entirely ceased production of any hub gears. They made about 100000 gears in their last year of manufacture; not enough to sustain a factory in Taiwan and a design office (in Germany I think) for them. Why did they make so few? Well there are various reasons;

- they relocated the factory to Taiwan about eight years ago; there have been numerous quality problems since then

- the pre 2010 range of hub gears included a fairly well proven 3s gear, a daft 'I-brake', as well as 5s and 7s hubs that were internally robust (being based on older twin-toggle designs) but externally troublesome, using a fairly crummy clickbox and an unreliable arrangement of pushrods. There was also the I-9 hub, which was again mostly OK internally but saddled with poor quality parts externally.

- Shortly after production moved to Taiwan they (re) launched the 2s automatix gear, modified the 3s to a hidden cable design, dropped the 5s and 7s gears (being old hat) and also dropped the I-9 gear (being seen to be more expensive than the better-shifting Alfine 8 and only a little bit (if any ) of an improvement). New G8 and G9 hub designs were announced. The result was that

- the 2s automatix gears were OK, but pricey for what they were
- the new 3s gear was a pile of poop, with all kinds of problems and priced out of budget OEM use by the SA 3s gear and probably the Nexus 3 gear too
- the G8 and G9 gears were very late to market and (for whatever reason) sold so poorly that they stopped producing them about a year after they were first available for sale. ( I have never seen one in the flesh, only pictures!).

-when they stopped the G8 and G9 they said that they would concentrate on 2s and 3s gears.

- after about a year or so of that they announced (a few months ago) that they were not going to make any IGHs any more. In the preceding year they had only sold 100,000 gears (vs a typical production figure in the previous 20 years of up to 1,000,000 units) . Some new bikes still have SRAM IGHs in, but as of now they are using up stock, not making them, and no-one in their right mind is going to buy a new one at any price because they have also announced that they are not making any more spare parts for them; once stocks are gone that is it.

FWIW I have special modification for SRAM/Sachs 5s and 7s gears that turns them into a reliable gear, reverting them to a twin toggle arrangement, independent shifters, and using mostly modified SA parts. I regard this as a sustainable arrangement because the external parts can be bought still (being SA parts for the most part) and the internal parts are basically reliable in those gears. In the (extremely rare) event of internal gear failure there are enough scrap hubs and NOS internals for now; plenty of these gears are being scrapped now because the shifters and clickboxes are already difficult to obtain and it is perceived that you are on a hiding to nothing with them in the long term.

cheers

-
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vandjq
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Joined: 16 May 2007, 11:30am

Re: Problem with internal cabling to hub gears

Postby vandjq » 10 Apr 2018, 8:47pm

Train, boat or long ride? Or you could just go somewhere in this country like Cambridge and visit one of the shops there like Bicycle Ambulance that publishes list prices for hub gear work.


mjr - Unfortunately I live in County Durham where hub gears are as rare as hen's teeth. My LBS wouldn't touch them and have now closed down, sadly. My Nexus 8 is approaching its first service, so I asked the manager of the local Evans Cycles store whether they could work on them, but he said they would send them away (I wonder where). And it's a long way to Cambridge...sigh...the dreaming spires.

I wonder whether the Dutch have forums like this one?

Brucey - you have an encylopedic knowledge of the history of cycling, comparable with the late Sheldon Brown. :)

vandjq
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Joined: 16 May 2007, 11:30am

Re: Problem with internal cabling to hub gears

Postby vandjq » 30 Apr 2018, 12:34pm

An update - I followed everyone's advice and replaced the Revoshifter, cable, housing, waterproof boot and cassette joint (CJ-8S40). The cable, housing and boot came with the new Revoshifter from SJS cycles (very reasonably priced). It had the requisite metal ferrule pre-fitted. I lubricated the cable with Teflon grease and cycle oil. I also fitted the cable to the outside of the frame, so there are no internal runs and there is continuous lubrication (in theory). I carefully filed the end of the housing at the shifter end and crimped a metal ferrule on. When I moved the yellow mark from 1 to 4 it lined up perfectly, and also from 5 to 4. This morning I did my usual 5-mile commute to work. My first impression was that gear changes were smooth and easy. But after one mile there was a very slight slip in 4th. Then after 4 miles there was a significant slip, one of the worst I've experienced.

Could it be the hub rather than the cable? :?

Brucey
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Re: Problem with internal cabling to hub gears

Postby Brucey » 30 Apr 2018, 12:54pm

the cable could have settled slightly; did you check the adjustment after your ride?

Also, as I mentioned previously some hubs require a cable adjustment that is slightly off the marks in order to operate reliably.

Since it is easy to try, adjust the cable 0.5 to 1mm more (i.e.tighter) than normal, make sure that the alignment is exactly the same on both upshifts and downshifts, and see if that makes any difference.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

vandjq
Posts: 66
Joined: 16 May 2007, 11:30am

Re: Problem with internal cabling to hub gears

Postby vandjq » 30 Apr 2018, 1:46pm

Brucey,

I've just checked the yellow marks and they are perfectly lined up from 1-4 and from 5-4. This is the first time I've been able to achieve that, which suggests lubrication works (on the cable). Last time I tried it with the marks slightly mis-aligned it slipped in 3rd. I presume you are suggesting there may be some slack in the cable which might be take up by a slight tightening. Does the adjuster tighten clockwise or anti-clockwise?