Current SA 5sp hubs, which one is which?

[mzjo]

I am being tempted by an SA 5sp IGH, not least because they are affordable and I could appreciate having a bit more gearing than the AW (which I like very much).
The questions are:
1. Which one is which? I want one that doesn't have drum or retropedal brakes (although presence of disc mounts isn't a deal stopper; aesthetics aren't that important).
2. I want it to fit in a 126mm width  frame (without stretching)
3. It will be used with drop-bars (although since I can fit a flat-bar shifter on the vertical of the quill stem that isn't a vast issue).
4. I am very taken with the idea of the rotary change, if only because the AW's selector chain gets clouted by the heel of my sandal. Otherwise I have the downtube and bracket fittings sitting idle while I fit a classic roller to the seat tube.

I read a post on another forum by Brucey which cast doubts on the absolute reliability of the latest hubs - but that was in 2016. Have things changed (for better or worse) since then.

What are the panel's views on this one.

[Brucey]

the hub that most closely fits your wish list is probably  the SRF5(W). You can still buy this (it is in stock in several places) but it is (apparently) no longer manufactured by SA. It is narrow enough, doesn't have a brake included etc.  It does however have a toggle chain. To give extra heel clearance this can be fitted with a short nut  and a different control rod (as per the S3X), although this does make the gear adjustment rather fiddly.

This hub has multiple problems but given a few givens can give reasonable service. One feature which may be appealing is that it is usually possible to build a 3s internal that goes into the 5s shell, so that in the event of problems, you can carry on using the bike without a lot of aggro.

The alternative is the current RX-RF5 hub with rotary shifting. This can be bought spaced to 125, 128 or 135mm, with different length axles and locknut/spacers. There is a specifications document on the SA website.  This hub uses a slightly narrower range of gears and uses a similar strategy of sun locking to the 8s hub, but in this hub the sun locking is bi-directional (depending on the gear selected) rather than unidirectional.  The guts of the thumbshifter are just the same as those for the SRF5(W) shifter but the consequences for the hub seem less bad.  If this hub unerringly fails then I'd expect to have seen a few broken ones but thus far I have not. It is too early to say for sure but it seems to be less prone to failure than the SRF5(W) model. It is, however, a rather bulky, heavy hub; it is almost twice as heavy as the SRF5(W) model.

Note also that the sprockets used by both these hubs vary in fitment and available range of sizes; this may or may not be important to you. Note also that in narrow format, the chainline for the RX hub is only ~39mm, and whilst this can be varied with a dished sprocket, not all sprocket sizes are available in a dished form.

cheers

[Brucey]

Other options include

- S5/modified FW; most versions of these hubs can be made into a reliable 5s hub, using a 3s style pull chain on the right and a pushrod on the left. (You can make a pushrod work without a bell crank BTW.) Twin shifters are required. The hubshell will accept a 3s internal if it all goes belly up.

-SA 5s  'sprinter' (single toggle 1993-2009) hubs; these exist in dog and ball locking forms. Both can be made to work acceptably well, but they do have their quirks. Again the hubshell can be made to accept a 3s internal if needs be.

- Sachs/SRAM 5s hubs.  These are (IME) most reliable in their original (twin-toggle, twin shifter) guise. The later versions with a crappy (and soon to be unavailable) clickbox on the right side with nested control rods can be converted to twin toggle style, but it is not a job for an IGH novice.

-Shimano 5s hub, eg SG-5R35.  This is not distributed in the UK but can be bought via e-bay.  It is perhaps best thought of as a hamstrung (and slightly lighter built) Nexus 7s hub; IIRC one of the two gear stages is virtually identical, and the second stage is simplified vs a N7 hub.

- hybrid gearing systems; many IGHs can be persuaded to accept two or more sprockets, eg as per the Brompton setup; this can give a lot more gears whilst retaining the simplicity and reliability of the 3s hub.


cheers

[McWheels]

I can't help but feel the 5sp is neither fish nor fowl. Comparable freewheel 5sp vs 8sp: 5sp is 10% heavier, and costs about 10% less at sjs. The 8sp is lighter, covers a wider range evenly, and doesn't seem to come with the same internet-hive-mind opprobrium. I'm 3500 miles and counting on my X-RK8.

[Brucey]

The RX-RF5 may be  a bit cheaper because it doesn't come with a shifter etc.  The RX-RF5 and others of its ilk were claimed to be 'e-bike ready' when they were announced so perhaps the extra weight is justified there.

The SA 8s hub is a weird one; it has three gear stages in series and it only ever gears up. It therefore uses two or three gear stages in series in gears 5,6,7,8, i.e. the gears that you will use most of the time are going to be the least efficient. A single stage is used in gears 2,3,4 and gear 1 is direct drive.  This makes the 8s hub problematic for use on a large-wheeled bike (it is difficult to get a chainwheel small enough to get a low gear for utility use), and renders the hub about as inefficient as any IGH going.  To cap it all the primary gear stage has lousy planet gear bushings and wears out prematurely.  I've seen 8s hubs break in about five different places, and it doesn't seem possible to buy individual spare parts,  so overall I find them very hard to love.  I guess if you have a small wheeler the shortcomings are compensated somewhat by some other elements of the design.

The opprobrium directed at SA 5s hubs is widespread but often misplaced.  The biggest problem with the 'sprinter' hubs was the intolerance to bad adjustment; the hub didn't manifest much in the way of distress before it just broke.  The 5s (W) hubs share the same issues and have some extra ones too; poor quality planet gear bushings, poor lubrication and the most common shifter (the 5s(W) thumbshifter) is not fit for purpose; it has too much backlash when it is new and it gets more and more as it is used. The backlash is 'sticky' too; i.e. after each downshift the lever sticks between gears and this causes the hub to break. It is sensitive to adjustment but a better shifter, better lubricant and careful adjustment normally  renders this hub quite serviceable.

All SA 5s hubs have a direct drive middle gear (gear 3) and (depending on the way the gearing is set up) that makes them intrinsically efficient when it is most needed; for example on my carrier bike gear 3 is used on slight uphills and/or with a heavy load on.  Depending on the duty cycle in various gears different hubs may suit different uses.  The 8s hub might suit folk who spend most of their time plugging away in bottom gear up long climbs for example.

FWIW I think there is no such thing as a perfect IGH, any more than there is a perfect derailleur transmission; it is a question of choosing which set of compromises are going to suit you best.

cheers

[mzjo]

I am biased against the 8s because of the gear staging, for my needs there is no appropriate sprocket chainring combination (28/24 or 24/24 do not appeal to me as gear combinations). The same problem exists with the current SA 4s.

There is an SRF-5 in stock at Hollandbikeshop at a very interesting price (under 100€ posted). Presumably this would be NOS non-wide version. The question is were these complete dogs or could they be made to work reliably with a bit of good sense and TLC? Also are the shifters the same as the later -W models or are they generally available. For not much more money there is an X-RK5 (that's what they call iti which looks a lot chunkier but I don't know if it will go to 126mm. Also not -W. The W is missing on the shell on both of these so it is reasonable to assume they are not wide range (but I actually like the older closer gearing). Same questions apply re shifters and reliability.
 Thanks for all the help!

[Brucey]

the immediate predecessor to the (W) hub was the ball-locking 'sprinter' hub. It changed little from its manufacture in Nottingham to Taiwan.   This hub can be made to work reliably but you need to use the all plastic shifter (still sold as a Brompton part) or you need to use the specific version the thumbshifter with the red bezel; this has the correct cable pull for this hub.

Some folk believe that the ball-locking scheme simply isn't strong enough, and cite damage to the sun pinions/balls as evidence of this.  I believe that if the gear adjustment is wrong, or the shift is not complete, you can get both suns locked at the same time, which causes one to orbit very slowly vs the other one, i.e. with enormous mechanical advantage.  The forces which can be thus generated I estimate to be about five times higher than any that would arise in normal operation of the hub.  Yes the hub is vulnerable to damage this way, but (IMHO) no, the scheme isn't inherently too weak.

Some shifts (2-1 downshift being a case in point) will only go smoothly if the correct shift technique is used; IME freewheeling or backpedalling don't allow the shift to 'go' every time, and the result is that one of the shift control springs in the axle is compressed and the shift tries to go as soon as you pedal forwards again. The shift control springs are damaged by repeated treatment of this type or worse yet being left compressed for periods of time.

cheers

[mzjo]

One SRF-5 hub ordered. I'll wait until it gets here before ordering shifter and sprocket because I still am not sure if it's the closer ratio hub or the wide. The site has both shifters with little indication of hich one is for which. I have to order a new seal for the Alfine from SJS so sprocket, nuts, anti-turn washers, shifters etc can come at the same time.

[Brucey]

if there is a generous chamfer on the left end of the axle, that usually signifies it is a ball-locking hub.

cheers

[mzjo]

My new hub arrived today. A box full of surprises!!!
First up it is the complete kit. The website says "complete hub" but that was just as likely to mean the hubshell was present. The truth is it is the complete SA box of bits.
Second surprise it is the -W version! Complete with the black bezel shifter that Brucey says it "unfit for the purpose". And the anti-rotation washers! It is 120mm OLN (reading the vernier without my reading glasses) so that's fine.

Total cost of the operation 95€ and a few cents, ordered saturday night, arrived today - 4 working days which is not bad at all. Well pleased on that score, seems a good deal. Now up to me to keep it working (or order a spare set of internals from the same site; they are available for not too much zorros).

[Brucey]

you can use the shifter unmodified provided you are prepared to pull the shifter back to the detent position following every downshift.  When the shifter is new it appears as if you don't need to do this, but the amount of backlash increases as the shifter is used and this means it is only a matter of time before serious problems arise if you don't get into the habit.

It is possible to modify the shifter so that the spring tension in the hub is enough to pull the shifter back against the detent, but this ain't easy.

cheers

[GavinC]

Brucey, what's your view on the DLS52 'Rapidfire' style shifter for (W) 5 sped hubs. I've used one for a while and it seems to give pretty positive shifts. I've also used the fugly 'Nimbus' plastic thumbshifter and although it's cosmetically challenged it gives crisper shifts than the metal thumbshifter.

[mzjo]

you can use the shifter unmodified provided you are prepared to pull the shifter back to the detent position following every downshift.  When the shifter is new it appears as if you don't need to do this, but the amount of backlash increases as the shifter is used and this means it is only a matter of time before serious problems arise if you don't get into the habit.

It is possible to modify the shifter so that the spring tension in the hub is enough to pull the shifter back against the detent, but this ain't easy.

cheers

I notice that there are downtube and barend shifters also available for the 5-W. Do these share the same mechanism as the thumbie? Are they any better engineered or just the same story?

Incidentally the vague indexing may well be a cultural thing at Sunrace. My 8sp downtube levers are like that as well (the 7sp Sachs dt shifters worked altogether much more precisely; the Sunrace levers work with a Shimano cassette - with ramps and things - but haven't a hope with an ARIS 8sp freewheel; the Sachs ones work with anything, indexed or not).

[GavinC]

I notice that there are downtube and barend shifters also available for the 5-W. Do these share the same mechanism as the thumbie? Are they any better engineered or just the same story?

The Sturmey bar-end, downtube and thumbshifters are identical.. it’s only the mounting hardware that differs.

[Brucey]

Brucey, what's your view on the DLS52 'Rapidfire' style shifter for (W) 5 sped hubs. I've used one for a while and it seems to give pretty positive shifts. I've also used the fugly 'Nimbus' plastic thumbshifter and although it's cosmetically challenged it gives crisper shifts than the metal thumbshifter.

The Nimbus shifters work (when paired with the correct hub) but are not going to last for ever. All-plastic shifters are basically a crap idea.

The SA trigger shifters are of course a version of a microshift trigger shifter.  I cautiously give the appropriate model a thumbs up for use with the (W) hubs.  However that doesn't mean that all such shifters (based on the same architecture) are any good; for example the Microshift shifter (based on the same design) that is meant for the Nexus 7s hub is complete rubbish; the cables always break inside the shifter because of a stupid design fault.  I think this doesn't happen with the SA versions I have seen but there is no reason to suppose that similarly stupid problems might exist in some other similar shifters.

cheers

[mzjo]

I have started to put the bike together. Today I have mounted a provisional shifting set-up, using the thumb lever mounted vertically on the quill stem. Putting the lever on the lhs of the stem keeps the cable out of the way of the brake cable (or will do when that is mounted; note rear brake on the rhs lever). All the plastic gubbins provided by SA is not much use at all. I wanted to use the fulcrum arm mounted on the rear wheel but with this in place the end of the axle is no longer visible in the wheel nut, which will make setting the gear adjustment a bit dodgy. I have finished with a composite cable arrangement based on the classic SA AW set-up, cable outer up to the fulcrum clip provided by SA which is mounted just above the rear brake bridge and cable inner direct to the hub nut, with no further bits of plastic or metal in the way. I wanted to use a neat axle nut cap provided in the kit but this would have directed rainwater directly into the hub via the selector rod so I have left it off.
Testing the hub on the stand has shown up a potential shifting problem that I am going to have to come to terms with. Gears 2,3,4 all change very smoothly. However change 4 to 5 can block the hub so that the cranks lock, as can change 2 to 1. This showed up the instant I adjusted the cable on set-up. The instructions say adjust the cable in 2nd gear then turn the cranks and change up to 5 and back to 2 to check the setting. I couldn't get into 5! The cranks locked. Adjusting the cable a turn or two slacker on the rod connector got 5th back but trying the changes while turning the cranks showed a need for extreme sensitivity with the 4-5 and 2-1 changes to avoid the cranks blocking. 5-4 and 1-2 work smoothly. The hub is noisier in 5th than in 4th but not radically more than my Alfine so I guess that's normal.
My first impression is that I can see exactly why these hubs might be very readily broken with poor changing at the extreme ends (particularly 2-1, which is a change one usually makes under duress at least a bit). I don't think all the blame can be laid at the door of the shifter.
One thing I did find playing with the hub before building the wheel was that it was most unwilling to "backpedal". I have seen somewhere the advice to lubricate the new hub before use (can't think where) so squirted a lot of light oil down the rod hole (proper 3in1, not the aerosol) and this seemed to help a lot. These hubs appear to be greased (according to SA info). Could it be that the grease has hardened in stockage and this is causing the shifting problems?
Is 5th the best gear to leave the hub in while not in use - like top on an AW? Is there any chance that the cable pull of any three positions on the shifter would match with an AW (I am tempted to keep the possibility of using my AW equipped wheel)?

[Brucey]

in the (W) 5s hub some of the springs are always compressed, regardless of the gear selected, so there is no obvious choice as to which gear is best to leave it in.  The ones to really avoid is to leave it part-way shifted into gear 4/5 or gear 1; this compresses some of the springs that should only see compression occasionally.

FWIW baulky shifting into gear 5 and into gear 1 with a new hub is partly due to the hub design and partly due to the fact that the hub hasn't been run in yet.  There are parts in the hub that have to be able to slide freely (if shifting is to be relatively smooth) and these don't move entirely freely when they are new.   Even when everything is as good as it can be the shifts into 5 and 1 are not perfectly smooth; the NIG requirement means that on a dog-locked set of sun pinions, both suns are effectively locked at the same time, mid-shift, and one sun is then kicked out of engagement when the shift is completed.  In some shifts this last part is only readily possible if the torque applied on the hub is fairly low and in the forwards direction.

 One of the things I intend to try is to fit a shorter set of axle keys in a 5s(W) hub (e.g. from an S3X hub...?); this will give no NIG action but might give smoother shifting.

FWIW the sun locking in the current C50 hubs s meant to overcome the issues that are described above. However it isn't clear yet if these issues are not replaced by other ones.

cheers
cheers

[McWheels]

That's a lot of care and attention to things for the 5sp.

To answer the 8sp points.
- Agreed it's not especially efficient, but I'm not racing and my only competitor is myself. Differential to the 5sp unclear, but it won't be as much as a single-speed.
- Choose your chainring carefully given the 1:1 in 1st. I run 26" wheels, so 33T to 25T sprocket. Low end gets me up anything down to 4mph. Top doesn't spin out until past 35mph, so it's about right. Start on flat ground in 3rd. 700 wheels would probably force me down to 30 or 31 but the forks won't take it so that's moot.
- Never had a shifting issue
- Never had to worry about what gear to leave it in
- Never serviced it in 4 years and 3600 miles
- My overall take on the efficiency is that I could lose more on soft tyres than any amount of internal gearing or the always-on dynohub. I've come to quite like the fizzing/buzzing noises from each gear, and given the peculiarities of the 5sp explained here, I'm not sure I'd ever go that way now.

[Brucey]

FWIW your 8s hub should be run in by now, but IME the factory lube ain't great so now is your chance to improve matters. If you don't do this the first (rightmost) gear stage will wear out on the planet gear bushings sooner than it should.

If you wait much longer you may not get the chance to try a new SRF5(W) or an X-RF5(W); they are no longer being made.


I would suggest that you consider using a semi fluid grease (SFG) in your hub; the SFG that is used in land-rover front swivels is pretty good stuff, the closest you can get easily to an ideal for this application.

cheers