Cycling UK Forum

Yesterday I mended my wife's rear puncture in her sit up and beg Dutch style bike. Never having done so before, I had to refer to YouTube to understand how to disconnect the brake and the gears from the Nexus 7 Hub. All of the advice mentioned using a 2mm Allen key to partially rotate the side of the hub, release the tension in the gear cable and slip the end out of the connector. I spent ages trying to find the hole in which to insert the Allen key. I prodded everywhere but to no avail. In the end I gave up but soon found I could easily push the appropriate disc/ring with my finger.
I am still baffled though: is there really a hole that I missed? Perhaps I need my eyes testing.

burroc wrote:Yesterday I mended my wife's rear puncture in her sit up and beg Dutch style bike. Never having done so before, I had to refer to YouTube to understand how to disconnect the brake and the gears from the Nexus 7 Hub. All of the advice mentioned using a 2mm Allen key to partially rotate the side of the hub, release the tension in the gear cable and slip the end out of the connector. I spent ages trying to find the hole in which to insert the Allen key. I prodded everywhere but to no avail. In the end I gave up but soon found I could easily push the appropriate disc/ring with my finger.
I am still baffled though: is there really a hole that I missed? Perhaps I need my eyes testing.

Took me a while to find the one on my partner's Alfine8, but once I had it was a lot easier on the fingers! I imagine I ended up flat on my back wearing a headtorch - that seems standard for me whatever job I'm doing recently [emoji23]

I'm a trendy consumer. Just look at my VOG-L09 using hovercraft full of eels.

burroc,
that thing that you are rotating is called the cassette joint.

You can find an exploded view datasheet for it on the Shimano technical documents website here

There is more than one type of cassette joint. If you look in the document linked above it shows pictures for one called CJ-NX10 and another called CJ-NX40 but they are compatible with each other and work the same. You can see the arm that takes the gear cable outer. I am going to assume that this arm is horizontal in that drawing and also on your bicycle (It is on more than one of my bikes). If you put your bike into gear 1, the cassette joint will be rotated into a position that looks exactly like that drawing (either of them). Imagine looking at the cassette joint from the the right hand side of the bike along the line of where the axle should be. If you look at the 9 o'clock position, there is a little tab at the outer edge of the cassette joint. That tab has the hole in it where you can stick the 2mm allen key. (It also take an old spoke which is the same diameter).

When you are ready to take the back wheel out, it is probably easiest to

1) put the gear selector into gear 1

2) pop the 2mm allen key into the hole in the cassette joint and rotate the cassette joint to slacken off the gear control cable inner (the return spring in the hub will want to keep the gear cable inner taught).

3) pop the end of the gear cable out of the cassette joint while the gear cable is slack

4a) If you have a CJ-NX10, slip the ferrule, on the end of the gear cable outer, out of the horizontal arm of the cassette joint. This entirely disconnects the gear cable inner and gear cable outer from the cassette joint. The rear wheel can then be removed from the bike with the cassette joint still attached to the hub.

4b) If yo have a CJ-NX40, slip the bits labelled item 15 in the document above out of the horizontal arm of the cassette joint. That will entirely disconnect the gear cable inner and outer from the cassette joint. Then you can remove the rear wheel with cassette joint still attached.

It might be that you can't get the gear cable outer to release from the cassette joint because it is too stiff to shift. Try using small pliers to grip them in that case, but don't be too brutal that you damage the ferrule or item 15. If they won't shift you can remove the cassette joint from the hub using the cassette joint fixing ring (item 10), but that is a last resort because refitting the cassette joint is a real pig. Ask again if you have to do that.

5) putting the wheel back. Get the wheel in the dropouts with the arm of the cassette joint facing the right way. Slip the gear outer back into the arm of the cassette joint. Make sure it is all the way home because if it isn't or shifts after you have assembled everything, the gear selections will be out.

6) rotate the cassette joint with the 2mm allen key

7) pop the end of the cable back into the circular slot in the cassette joint. Notice how the pieces that make up item 8 are orientated.

HTH

Wheel removal is so much easier when you have a Rohloff with the Ex shifter box, I find it quicker than removing a derailleur wheel.
One benefit of paying all that extra money for your IGH!

Mike

I find Shimano IHG gear cable removal a real faff. Pops out easily if you push, twist etc at just the right angle/direction. I don't do it often enough to remember the exact knack.
What I do is remove the wheel with the gear cable connected,leaving the wheel tethered to the bike. Then remove the tube/tyre on the left side. If there is a hub brake on the left side, cable removal is much easier.
If you have the bike up in a work stank, a large spaner through the spokes resting on the chain stays supports the wheel, avoiding strain on the gear cable.

I've dealt with the same hub. It's worth removing and cleaning the cassette joint and the cable while you're at it, since a bit of stickiness causes no end of problems when shifting to a higher gear.

If yours has roller brakes, these are equally tricky to disconnect. Slacken the cables first using the adjuster(s). It helps.

Thanks for the interesting and thought provoking responses. Just so there is no confusion - I did successfully remove the wheel, my query was just out of interest. However, despite using a good quality light, stronger glasses and the Shimano parts diagram, I still cannot locate the relevant hole. Nevermind!
On a related topic though: it was only when I took the wheel off that I nioticed a small plastic cap over a hole adjacent to which is the instructuion to "grease". It is barely accessible with the wheel in place, which seems odd. I'd be interested to know how often grease should be applied and what particular grease is necessary. In simple terms, what do I need to buy? Many thanks.

Roller brakes? You buy a bottle of the Shimano special roller brake grease, the nozzle fits in the hole and you squirt some in once every...er...many years. They are like coaster brakes - they run bathed in grease, which seems counter-intuitive for a brake!

I did find the allen key hole on the one I did, but you can just turn the joint by hand. Given that this kit is aimed at casual riders, it is incredibly complex to work on!

rogerzilla wrote:[snip] Given that this kit is aimed at casual riders, it is incredibly complex to work on!

I would certainly agree with that, though when the hub is working it works very well.

I would suggest that anyone who gets a new bike with one of these Shimano hub gears for the first time should take it home and immediately take the rear wheel off to practice. At home it will be clean, dry and warm and you will have all the tools that you need at hand.

Even better, if you are buying the bike from a bike shop, get the staff at the bike shop to demonstrate how to do and then let you the customer try do do the same before the bike even leaves the store. Not all stores would be prepared to do that, but I would hope the good ones would. I think Third Crank might have made that suggestion in the dim and distant past.

You don't want to be learning how to do this at the side of the road in the middle of nowhere the first time you have a puncture. I was fortunate, my first puncture occurred while I was at work.