I vaguely remember reading somewhere that the reason for the empty "neutral" between 2nd and 3rd on the old hubs was that they had to do this to absolutely prevent 2nd and 3rd both getting engaged - the hub instantly self-destructed if this happened.

Regarding the planet pinion axles, I have always thought that making the pins with a slight widening taper on those ends, with a matching angle on the clutch, would solve the problem of accidental disengagement. (Actually perhaps I read that in one of Brandt's posts as well.) Perhaps this is what Sunrace SA did.

I am guessing the additional pawls are for eliminating the neutral, so that even if it disengages, it doesn't cost the rider their b*lls.

I am sure that the change in shape of the planet axle pins is to do with ensuring better engagement, and maybe they are tapered outward by a thou or two. I didn't examine them that carefully, only noting that they are radically different in shape to the old AW ones. The other thing to say is that the driving of the ring gear in first and second gear is different to the way it was done in the old hubs, since that drive is engaged by the new set of pawls on the driver operating inside the right hand end of the ring gear on a new set of dogs. These pawls can be engaged and disengaged by the cross shaped clutch assembly that slides inside the driver and the ring gear. The other possibility of difference in top gear engagement would be the shape of the dogs on the left hand face of the clutch that engages with the planet axle pins. In fact the clutches and drivers on the old and new AW hubs are entirely different. On the old aw the clutch is just a simple metal cross whereas the new one is much larger and more complex. The old AW driver has a male style of engagement with the clutch, whereas the new one is essentially the opposite. It is worthwhile looking at the Hadland old AW clutch and driver diagrams alongside the New sunrace NIG ones. The differences are pretty significant.

Thank you for the clarifications of the AW forward freewheeling and SA8's quasi-forward-freewheeling (any higher gear suddenly down to 1st). I stand corrected on the internal differences. But the outward symptoms, as far as the rider pedaling the bike is concerned, are very much the same.

I must disagree with you when you opine that it is a very minor problem. The quasi-forward-freewheeling did happen to me on an SA8 this past summer, before I had ever heard anything about it, and I almost tumbled off the bike into traffic. The loss of resistance occurs suddenly without warning.

Jobst Brandt viewed the sudden forward freewheeling problem as a safety concern too, and I'm relatively certain he would feel the same about the SA8's slipping into 1st, since the symptoms for the rider are virtually identical. Brandt, BTW, for those who are unfamiliar with his name, was an engineer at Porsche and Avocet and has written the definitive text on spoked bicycle wheels.

If cable-adjustment is the problem ... (I say "if" because SA blamed the AW's issues on cable adjustment too, which Brandt showed to be wrong) then all I can say is that the shop tech where I tried several bikes with SA8s could not get the cable adjusted properly after repeated attempts. But let's stipulate that cable adjustment is the problem. If the cable should fall out of adjustment when you fold the bike, and the result of that mis-adjustment is the possibility of tumbling over the bars or slipping off the pedal because of the sudden loss of resistance, then in my opinion the currently stocked version of the SA8 is unsuitable for folding bikes; SA should release into circulation the new SA8 that is said to fix the problem, and take back from distributors all old stock.

Regards
T

P.S. This isn't a "hot cup of coffee" issue where a slightly more careful and slightly less stupid consumer could have prevented relatively minor injury; it involves unsuspecting consumers who would be victims of a design flaw.

The sudden "top to neutral" thing is a bit of a problem. I still have a lovely scar on my knee cap 20 years after the 3speed hub on my BSA "meteor" shifted to neutral whilst i was pedalling home from school. The sudden neutral caused me to slip off the pedals, chip a tooth as my chin landed on the stem then crash on a freshly resurfaced (sealed and chip) road. My one clear memory is of staring at my knee and seeing a white patch surrounded by blood. the white bit was bone.

That said,the SA 3speed hub is a marvel of robust engineering. If they are kept oiled they go forever....

I now have a F&S 2 speed duomatic and like that a lot.

Just a point of clarification....

Reading this quote above, excerpted from an exchange on Hubstripping.com, one could mistakenly conclude that it was Brandt who was making some "claim" in 2007, since the original poster (TCS) uses a locution that obscures the identity of the person:

"... still to be claiming in 2007... is in error"

immediately after referring to Brandt. TCS is actually responding to another poster in the exchange there on the hubstripping.com site, who happened to allude to Brandt's earlier (2002) remarks about the SA hub's gear slipping issues. TCS is questioning that poster's motives, not Brandt's. TCS should probably have told the poster that he was not up-to-date on changes in the design; to impugn his character was uncalled for.

Regards
T

While I have a hard time envisioning any folder on a century ride, I have a Dahon Speed Pro TT that I think could make this possible. I have ridden it as far as 40 consecutive miles and found it to be just as comfortable and almost as fast as my Trek road bike. I should note that I am a petite woman (barely 5 feet tall), so that might have something to do with my own comfort factor on a small bike. However, the hub gear on this baby means that it can really fly. It folds down fairly small (not as small as other Dahons, but small enough so that you can bring it on the Metro during rush hour). Overall, the bike performs great, although like all folders it can be a tad more temperamental from a maintenance perspective.

So your claim is that the current production Sturmey-Archer three-speed still presents the rider with the same fault?

tcs

The very sudden no-warning drop in pedaling resistance can cause you to lose control of the bike and/or fall off. The (old) SA 3-speed's drop into neutral and the (current) SA 8-speed's drop into first, though they may differ in their etiology, do present the rider with much the same risk of potentially very serious bodily injury or worse.

See, for example, http://www.bikeforums.net/showthread.php?p=7979202#54

Regards
T

P.S. Again, there is reportedly a new version of the SA 8-speed hub in which this problem (innocuously called "adjustment sensitivity" on the Sunrace/Sturmey-Archer blog) is said to have been eliminated. SA has said that the new version will be released after U.S. distributors have sold their stocks of the old version: "Once any remaining 8 speed hubs that are in the US are sold, our distributors will be supplied with the new version."

SA gears are fine. I see someone popping up with the same old ''flaw' argument again. Talk about axegrinding across the various threads.

Go take a ride on an SA-8, mulleady. Old (currently available) version.

Already had one on a Downtube FS, it was an excellent ride thanks! ;)

As one of the many who has complained about the adjustment sensitivity of the SA 8-speed hub, I think I should mention that several months ago I put a Nexus red band 8-speed hub on my old Trek touring bike and set it up so the gear range would match that on my Downtube Mini as well as possible.

In favor of neither hub, I must mention that the two shift in opposite directions; on the Shimano, turning the shifter towards the thumb is an upshift, on the SA the same motion is a downshift. This is annoying, and makes it difficult to switch back and forth between bikes with the two different hubs; I will probably solve this problem by mounting the Nexus shifter on the left handlebar. Oh, and just to keep everyone on their toes, the Rohloff shifts like the Sturmey Archer, and the NuVinci shifts like the Shimano.

Otherwise, the steps between the gears of the Nexus seem much less even than those between the SA; as a result it seems easier to find the right gear on the SA than the Shimano.

Both hubs may unexpectedly slip into a lower gear if something goes wrong with the shift-- if you inadvertently turn the shifter, for example, or if you inadvertently prevent it from turning a the whole gear increment. The same thing can happen if you have the cable adjusted wrong.

This leaves two questions in my mind:
--is the Sturmey Archer mechanism more difficult to adjust than the Shimano's? Not to me! but perhaps this is a matter of familiarity (I am more familiar with the Sturmey Archer).
--is the Sturmey Archer mechanism's adjustment more sensitive than the Shimano's? I suspect it is, but I am not quite sure yet. The difference is subtle.

All in all, at this point I cannot say either the Shimano or the Sturmey Archer 8-speed hub is vastly superior to the other. In general I prefer the shifting of the Rohloff and NuVinci, but the latter have their own shortcomings --price and weight, respectively.

One thing you can do with the Nexus 8spd hub is to get a Shimano trigger shifter made specifically for the hub.. inadvertent shifts vanish and more positive shifting ensue... I use one on my Swift.. big difference.. well documented on MTB forums also..

Now that this thread has been hijacked I might as well throw in my 2c.

Yeah, but that kind of ruins one of the biggest advantages of having an IGH: its easy to shift multiple steps simultaneously (ie go from seventh gear to first gear in one motion after you've safely stopped at that traffic light you were trying to beat).

Speaking of shifting multiple gears, I seem to have noticed that my SA8 doesn't have any shifting problems when I shift two or more steps at a time. Although it could just be a coincidence in the face of erratic operation, I'm thinking that shifting in multiple steps helps provide a buffer kinda like the neutral gear on the old hubs, which is fine with me because I think the middle gears are too close anyway.

Also I think the shifting on my hub has gotten smoother as the hub has broken in: I haven't had a slip to first in many many miles even though I've started pedaling while shifting.

All in all I like the hub. Even if it does have a problem unpredictably shifting to first, it's still safer and shifts better than derailleurs which are susceptible to chain drop. However, I don't think I'd buy another folder with one until the new model is released. It's a shame that this hub is so sensitive to cable adjustment because the low direct drive is really meant for folders.

Derailers, in my experience, drop their chains when the bike is ridden over a fairly large bump or off a curb, and therefore the rider can almost always anticipate the jolt and hold onto the bars more tightly, and adjust pedaling and riding position accordingly; whereas the SA8's slip into first gear and sudden loss of pedaling resistance happens without any warning whatsoever.


Regards
T

7th to 1st in one motion, not really much call for that in everyday situations.. perhaps you haven't tried a rapidfire shifter on a Nexus 8spd hub .. it'll shift as fast as you can wiggle your thumb.. other than more precise indexing over a twist grip shifter, it also allows both your hands to remain firmly on the grips as you brake and shift at the same time (now that's handy).. also it's easier on the wrist... a measure of safety actually.. now, where going from 7th to 1st in a single twisting motion is nice is if you also have a Schlumpf Mountain Drive or a High Speed with a 2.5/1 to one overdrive/underdrive, there you basically have two separate gear ranges with little gear overlap..

Well I can't say that's been my experience. The only time I've had the big slip is if I keep pushing it after a crunchy shift instead of giving the hub a chance to lock in gear.

Truthfully I suspect at lot of the issues people have with shifting internal hubs has to do with being too accustomed to derailleurs. Since the shift/pedal timing and tactile feedback for an internal hub is basically the opposite of a derailleur I think lots of folks are messing up their hubs by instinctively and subconciously pedaling and shifting with the worst possible syncronization every single time they shift. Stop using a derailleur for six months and then tell me how horrible the shifting is on Sturmey Archer hubs.

I do it at least 6 times a day (7th to 1st). Once coming to the traffic light at the bottom of each hill on my way to work and the same on my way home.

You are right, I haven't tried the trigger shifter for the Nexus (just with derailleurs) but I still think I'd rather stick with the twist grip. Like I said, I usually shift in steps of two because the steps on the SA8 are too close together, so why double my wiggles? Also, when braking I'd rather have as few distractions as possible. Different strokes I guess.

I have never said that "shifting is horrible" on the SA hubs. Rather, I've made a more specific charge ... the older 3-speed and the current 8-speed drop out of gear while the rider is pedaling, resulting in a sudden loss of pedaling resistance that can cause the rider to lose control of the bike. With the type of derailer chain drop you mention, typically the rider has eased up to make the shift and so, if the rider recommences pedaling with the chain not correctly seated on the cog, the rider has only begun to re-apply pedaling force. The scenario with the derailer would therefore be far less likely to cause the rider to lose control. When the SA hub loses pedaling resistance, it's like stepping with one's full weight onto a patch of thin ice; with the derailer, it's more like discovering the ice is thin as you test it with the tip of your shoe.

Regards
T

I have 2 8sp SA hubs. They don't drop to 1st gear once properly adjusted.

Fair enough, but allow me to point out that that's not a flaw as much as it's just the nature of the beast.

No machine will ever be perfect. As internal hubs are designed to ideally shift without pedaling they will always naturally be prone to problems at the opposite end of the spectrum (hard pedaling). Derailleurs, on the other hand, are designed to ideally shift while pedaling and, thus, are similarly prone to problems at the opposite of their ideal (easy or no pedaling). So no shifting mechanism primarily intended to be engaged without pedaling can be fairly expected to cope with pedaling which errs towards aggression as well as a derailleur.

So those of us that require the functionality of shifting while stopped simply need to be relatively more careful about the way overzealous pedaling may affect the shifting mechanism. If that's not an acceptible tradeoff for you, if hedging against the potential of self-injury due to hard pedaling is your number one priority, then don't expect to ever shift well while not pedaling because its unlikely that a shifting mechanism designed under the dual objective of shifting with and without pedaling will ever be able to match the best of what's been designed under a single objective.

jur, I would put faith in your assessment. But the issue with respect to folding bikes is that the folding itself may cause the hub to fall out of adjustment (insofar as the cable may be placed under some stresses during the fold). How often do you fold your bikes with SA8 hubs?

Regards
T

OK. The "nature of the beast". That prompts the question ... is the SA8 as reliable and safe as the Alfine or the SRAM iMotion in terms of its response to what you call "overzealous pedaling"? Those IGH's can "shift under load", IIRC. By your argument, they should deal better with "overzealous pedaling".

The second point I'd make is that I experienced the SA8's slip into first gear when pedaling with much less fervor than I'd associate with "overzealousness". And that less-than-zealous pedaling is the only reason I did not lose control of the bike and swerve uncontrollably into 45mph traffic.

Regards
T

P.S. I should also add that I weigh 88.8kg, and I believe makeinu is about two-thirds my weight, so your experience may vary.

Not on a regular basis, only as occasion to put it in the car demands. I usually shift to 8th gear when I do (but as often forget). But I can't say that folding is a major cause for trouble.

What I find gives more trouble, is riding on wet dirty roads. That almost always causes trouble on those gears which are the most sensitive. I am not exactly sure what happens, but likely it is dirt getting into the cable wrapping groove changing the effective wrapping length. On bad days I sometimes have to stop using those sensitive gears.

Well, bear in mind that there may be a lag. I personally don't think that you can get the SA8 to slip from 8 down to 1 without having 8 failed shifts, each just slightly grabbing a higher gear due to the extra friction of pedaling too hard while shifting. Then when you push it even harder the friction makes it bounce out of its delicate state back to the true gear (first)...but that's just my take on it. I suspect that if you twisted the shifter back to 1 and then back up to 8 again without pedaling (to get a reliable shift) just before pushing hard it wouldn't slip. Of course this is assuming that the shifter cable tension isn't way way off.

But maybe I'm wrong. Maybe I just don't understand because I can't put the same force you can. It's true that I do weigh almost half what you do, so I guess I'll never know.

PS. For the record, I don't think the SA8 would be as reliable as the Nexus or iMotion hubs, but those hubs are way more expensive, especially if we're talking about entire bikes like a Downtube H vs a Dahn Mu XL. Are cheaper hubs less safe? Maybe, but what cheaper component isn't?

You need a good layer of corrosion to seize everything in place. :P

The Sturmey8 will only slip into 1st if the shifter cable is mis-adjusted. The issue is that it is very easy to be slightly off, as the Sturmey8 is EXTREMELY SENSITIVE to being just right. It doesn't help that the markings on the hub that are supposed to correspond to proper adjustment don't actually correspond to proper adjustment, but are only in the ballpark.

Once you actually have the adjustment dialed in, mark the position yourself so that you can get it again in the future.

Folding and unfolding should not affect your adjustment, provided that the nut on the cable is tight, and cable routing is properly designed on the frame.