Nexus 8. Talk to me.

[bren]

Backstory: The Mrs has had it with conventional gears, through the course of two bikes I've tried her with thumbies, gripshi(f)ts, rapidfires the lot. In short she's a Luddite who is always in the wrong gear and wants to go SS but in a last ditch attempt I want her to try a geared hub as the hills around here are killers.

So I took a punt on a cheap nexus hub and shifter from eBay and it arrived today. Shifter (gripshift style) is a tad battered.
Is the hub compatible with other shifters? Pull ratio same as 8 speed rapidfires for instance?

Are there any checks I can make on an unmounted hub before I potentially waste my time building it up? It feels a bit notchy and clunky but to be honest I don't know what a new one feels like off a bike so all this could be normal for all I know.

 

[Andy R]

Re:

You can use the 8 speed Alfine trigger shifter but not the standard Rapidfire 8 speed shifters, as cable pull per shift is very different for the IGH version, which is also "rapid rise" style i.e. low/normal.

In other words, with a snapped cable or no cable fitted. the Alfine/Nexus will default to 1st gear compared to a standard rear mech which would default to the highest gear.
(You can also use a modified SRAM X9 shifter).

As far as checking before you build the wheel goes, I would certainly mount the bare hub in a frame with all the drivetrain assembled and make sure that it at least transmits drive in all gears (and that it is actually changing and the ratios are different in each position).

 

[bren]

Thanks!
I'll stick a frame on my stand and have a play tomorrow night then.
I've had another look at the shifter, and while it's covered in scratches and cracks it seems to function OK. Personally I couldn't live with a grip shift type shifter but SWMBO says she can.

 

[Andy R]

Re:

You know the basic set-up points, I'm sure, there's not much to do except make sure that the yellow marks on the hub line up in 4th gear - I always check it both ways, shifting up and down to 4th to make sure I have no sticking cable issues or anything.

This is (IMHO) the nicest 8 speed shifter for 8 speed Alfine/Nexux hubs - SRAM X9 with Zerode index plate.

 

[bren]

Thanks again, just had a play with it, all gears select fine, so after an oil change I'll build the wheel. Just need to find a tiny frame now.
I've read ATF is a good cheaper alternative to shimanos overpriced rattlesnake oil? Would you concur?
That shifter looks much more like it!! The grip shift style thing I have looks like it's been dragged down the road for a couple of miles!

 

[Andy R]

Re:

Plenty of people seem to have used ATF with no problems and, possibly, less drag so that's probably the obvious way to go.
However, whenever I've re-lubricated an Alfine 8 hub I've flushed it out with an ATF dip, let it drain well then lubricated with Rocol Aerospec 100 liquid grease.
This is used in the prop hub reduction gearing on the Bombardier Q400 (as used by FlyBe) so is perfect for the Alfine application and is less likely to migrate past the seals than oil. I use waterproof grease on the actual wheel bearing race.

I've got 5 litres of the stuff, so if you'd like some drop me a line and I'll pop some in the post to you.
I've also got an 8 speed trigger shifter if that's any use to you?

 

[bren]

Re:

That would've AWESOME!!! :shock:
You sir are a gent!
I'll PM you.

 

[bren]

So it's all serviced, new bearings and built into a wheel :8

Quick question for those in the know:
My no turn washers give me the situation pictured at the bottom here:

Now if the gear cable was chainstay routed I can see the issue, but in my case it's seat stay routed. Looks ideal to me? Is there some not so obvious reason that the cassette is meant to be horizontal?

 

[Andy R]

Chain clearance is the only reason. If you run the cable up the seatstay you might find that the cable stop part of the "cassette joint" (or whatever they call it) is exactly where the chain line is.
This will depend on which way round you are running the sprocket (most likely it'll be concave side out) and on the sprocket size - sometimes a bit of judicious bending can get round the problem but chainstay routing is the most problem free IME.

If you're going to bend the cable stop "arm" to gain a little clearance then it's best to strip the cassette joint down so that you can get it in a vice and get the bend exactly where you need it to be, without the risk of damaging any of the plastic components.

 

[bren]

Aha! hadn't appreciated the chain as I haven't mounted it yet!
Good info, thanks fella!