Author Topic: 8 speed chain's  (Read 541 times)

8 speed chain's
« on: December 30, 2019, 08:15:58 pm »
Hi all,
I am thinking of refitting the sram dual drive  system onto my trice as the 8 speed hub gear is proving to be unreliable on upshifts due to moisture getting into the cable and I suspect the barend shifter is not very precise. Also the gear range is okay for unladen riding but I think I will struggle with a camping load..
As usual I am having to find a cheap reliable chai 3 of. I have read online that there isn't much difference in wear rates in chains as it depends more on cleaning than price.
I was looking at the sram 830 chain on amazon but am interested to hear any suggestions to help me in my search  :)
the slower you go the more you see

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: 8 speed chain's
« Reply #1 on: December 30, 2019, 08:43:06 pm »
Well for a start you need to take the apostrophe out of the title  :P


SRAM and KMC are both safe bets, at your choice of price point.  Given that 8 speed chains only cost about £7 though, the differences between them are hardly worth noticing.

Re: 8 speed chain's
« Reply #2 on: December 30, 2019, 09:07:51 pm »
you don't say which 8s gear you are using, but if shimano then at the cassette joint end you can use a more weatherproof version of the cassette joint (CJ-8S40 from memory, to fit Nexus 8 and older models of Alfine 8) to deter water ingress. By using different NTWs you can arrange the cable run/cassette joint angle so that water isn't even trying to run down into the cable at the hub end.

FWIW the Alfine trigger shifters are also more precise than aftermarket bar-end shifters. It isn't difficult to create a bracket to mount one of those onto in most installations.  Any shifter/hub will of course be utter pants if the cable is full of water.

FWIW if you want the most durable 8s compatible chain, it may be worth looking at those 3/32" chains which are meant for IGHs on e-bikes; these are available with the latest hard surface technology and are long enough to run on a solo derailleur system. They ain't cheap though, you would probably still have to buy two for a trice and in some cases they are not designed for derailleur systems, so they'll run on 8s sprockets but may not shift as well as other chains.

Most folk running 8s just buy cheap chains and change them regularly.  It is not a bad plan.

cheers

Re: 8 speed chain's
« Reply #3 on: December 30, 2019, 09:51:20 pm »
The current hub is a alfine 8 speed and it changes down fine but even when new upshifts from 2 to 3rd and 4 were fairly in precise... I Don't think that the shifter is a alfine one but appears to be the only one available on the shimano website. I was expecting the shifter to be a twist grip one.
Due to the e assist I cannot improve the gear range unless I refit the dual drive. I really like the the simplicity of this system but I think I will struggle next year with a full camping load 🙂
the slower you go the more you see

Re: 8 speed chain's
« Reply #4 on: December 30, 2019, 10:24:58 pm »
Alfine-8 hubs used to be 'low normal' but newer ones are 'high normal'.  Bad upshifts could mean different things depending on which version you have.  Cables can be crap from new and interfere with the shifting.

A simple but revealing test is to shift to the index mark in either direction and see if the exact position of the markers is different. If there is more than ~0.5mm difference then the cable is probably bad and the shifting will be utterly rotten. 

FWIW Alfine hubs are optionally intended to be used with a tensioner and two or three front chainrings to extend the gear range.

SRAM dual drives are alright but they

a) often wear out the axle on the LH side because only one pawl engages in gear 1 or gear 2. The result is that the hub is merrily wrecking itself as you ride and is draggier than normal while you are about it.
b) they are no longer being made so spare parts are becoming more difficult to source.

In relation to a) the usual symptoms are that the planet cage wears a groove in the axle and/or the LH hub bearing starts to break up. Once the axle has a groove in it, the chances of having only one pawl engaged increase and the hub is basically doomed.

cheers

Re: 8 speed chain's
« Reply #5 on: December 30, 2019, 10:36:03 pm »
Hi brucey,
Do you know if the sturmy archer dual drive is any better?. I can get them from practical cycles  :)
the slower you go the more you see

Re: 8 speed chain's
« Reply #6 on: December 31, 2019, 12:43:32 am »
I quite like SA hubs because they are usually made well enough and you can buy spares for them. However with a few models one or both of these things does not apply.  The SA 'dual drive-esque' hubs (CS-RF3 and CS-RK3 etc) seem to lack spare parts backup; leastways you can buy a spare internal but other parts specific to this hub don't seem to be readily available.

Inside it is about as simple and as well made as the current AW hub but the high gear drive to the planet cage is via 'plunger pawls' which can stop plunging if there are tiny (by SA hub standards) particles in the grease.  If the drive slips in third gear the pockets the plungers go into tend to get chipped and this makes more particles, and..... well you get the picture. 

If you decide to nip this in bud by cleaning the internal, bad news; the plunger pawls cannot be removed for cleaning, which means that you can never be quite sure that you have removed all the particles in the spring pockets which might jam the plungers again.

There is also a small issue regarding the running clearance of the internal. Traditionally the running clearance in SA hub internals  is adjustable ( screw the RH cone home and then back it out half a turn) but in CS-RF3 etc the RH cone is screwed home and if the running clearance is too much, tough, you can't adjust it, not without machining parts anyway.  If the clearance is too much and there isn't enough grease in it then the hub can get a bit rattly.  CS-RF3 etc use a longer cable pull than normal, so that you can control the hub using a MTB front shifter if you want. What you cannot definitely do is use a standard SA 3s shifter.

If the CS-RF3 suffers major blow-up on the road then I would say you have a fair chance of making it work again (in the middle gear at least) provided you can fit new high gear drive pawls (same parts as AW I think) and removing the planet gears if necessary. [edit; thinking about this, I'm not sure this is readily possible in fact; the planet gears are permanently fixed into the planet gear assembly and if this is omitted, the ring gear is no longer located properly, meaning that you will lose drive in all gears. Parts pdf here http://www.sturmey-archer.com/files/catalog/files/300/PART%20LIST%20-%20CS-RF3%20CS-RK3.pdf ].

So in the short run there isn't that much to choose between the Dual drive and the CS-RF3/RK3 etc.; neither design is perfect.  In the long run I think the SA hub is a better bet simply because you will be able to buy some spare parts for it rather than virtually none.

cheers

Re: 8 speed chain's
« Reply #7 on: December 31, 2019, 06:46:13 am »
Thanks for the information brucey😄👍. I have 2 spare complete dual drive hubs to use but I also like the the s a option
I will go into thinking mode 🤔
the slower you go the more you see