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  1. #1
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    Downtube SA Hub X-RF8

    I've tried to read through the archives but does anyone know what the final verdict was on dealing with the cursed SA X-RF8 hub that keeps slipping? Did Sturmey Archer and Downtube just screw everyone with that hub or is there a fix? I like the Mini but don't ride it often and when I do, I remember why I don't. Help.

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    Eschew Obfuscation SesameCrunch's Avatar
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    Are you sure your shifter is adjusted properly. Are you familiar with the adjustment?

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    It's got electrolytes! chucky's Avatar
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    Not sure about everyone else, but mine just needed the cable to be adjusted a little tighter than the mark (just after the outer mark instead of at the yellow center mark). After I figured that out I've had thousands of trouble free miles.

    So I don't think there's anything wrong with this hub other than the adjustment mark being painted in the wrong spot.

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    BikingYupik BikeKraft's Avatar
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    It may be a cable problem. I'm starting to notice a little hesitance when up shifting, still works but slow.
    Not quite bad enough to get my fingers dirty.
    I really like these hubs. And I like the Downtube 8h also, though it's my daughter's.
    She's so pregnant at the moment she can't ride it.
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    I haven't tried to adjust it lately but I've tried different settings about 10 times. It is like third gear suddenly needs a shorter cable length. I guess I will try adjusting it again and again and again and again...
    Sesame, is the adjustment the ones given on the SA site? I've also just put it in 4th gear (if I recall) to line up the marks and when that didn't work, tried a hair more and then a little more and when it got worse, I tried the other direction. The best I've been able to do is just 3rd gear doesn't work.
    Last edited by crackerdog; 03-27-11 at 09:45 PM. Reason: added more

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    jur
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    The 1st version of that hub is notoriously sensitive tyo cable adjustment. A little dirt around the cable pulley area will also trash performance. So clean everything in sight at the hub, and give it your best go at adjusting. A slippy gear may remain, and I found it also depends on how well I released the grip shifter - but on the 2 hubs I had, both had different trouble gears that never went away completely.
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    OK, pootled around for a couple of hours, stopping to adjust the cable a tiny bit from one side of the marks to the other. The best I seem to be able to get is the 3rd gear slips unexpectedly. It is like the gear cable is suddenly too long. It seems like if I start to shift to 4th but hold it half way, the gear seems to work. If there was an adjustment for every gear in the twist knob, I could fix it.
    How about the X-RF8'w' hub? Now that a few people have had a chance to try it, is it worth the time, effort and money to change to that hub?

  8. #8
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by crackerdog View Post
    OK, pootled around for a couple of hours, stopping to adjust the cable a tiny bit from one side of the marks to the other. The best I seem to be able to get is the 3rd gear slips unexpectedly. It is like the gear cable is suddenly too long. It seems like if I start to shift to 4th but hold it half way, the gear seems to work. If there was an adjustment for every gear in the twist knob, I could fix it.
    How about the X-RF8'w' hub? Now that a few people have had a chance to try it, is it worth the time, effort and money to change to that hub?
    Is your axle slipping? That's another issue I had which also affected the shifting. Get a chain tug, grease the axle and tighten it down really good:
    3.jpg
    You only need an anti-turn washer on one side. Also, a lot of chain tugs won't fit the SA axle so get one that does or be prepared to file it.

    Also it might need to be broken in if it's been ridden misadjusted. Once I found the correct adjustment for mine it worked alright, but got better with some miles.

    Wait, this is for the Downtube Mini right? Does that bike have a unified rear triangle (with the suspension)? If not then I wouldn't expect it to work well (or at all).
    Last edited by chucky; 03-30-11 at 10:53 AM.
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  9. #9
    Eschew Obfuscation SesameCrunch's Avatar
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    Quote Originally Posted by crackerdog View Post
    OK, pootled around for a couple of hours, stopping to adjust the cable a tiny bit from one side of the marks to the other. The best I seem to be able to get is the 3rd gear slips unexpectedly. It is like the gear cable is suddenly too long. It seems like if I start to shift to 4th but hold it half way, the gear seems to work. If there was an adjustment for every gear in the twist knob, I could fix it.
    How about the X-RF8'w' hub? Now that a few people have had a chance to try it, is it worth the time, effort and money to change to that hub?
    Also, make sure you're not inadvertantly turning the shifter with your grip. I found that I was doing that early on. I experimented by making sure my right hand was completely off the shifter and just grabbing the handlebar grips. Then, the mysterious shifting subsided.

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    Quote Originally Posted by crackerdog View Post
    How about the X-RF8'w' hub? Now that a few people have had a chance to try it, is it worth the time, effort and money to change to that hub?
    There have been tons of reported issues with the XRF8 .. the newer 'W' (wider range at 325%) is being accepted much better... if you haven't already, you might want to check out the discussions on the SA Facebook page.. might be something useful for you there also..

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    About axle slippage (apologies if this is patronizingly obvious): When I got back into cycling a few years back Datako on the Dahon forums explained to me that I ought to tighten both bolts simultaneously to, I guess, distribute pressure evenly. . . I can't remember if it was his advice or me just figuring out the obvious, that the hub needs to be secured whilst the bike is on the ground, not suspended from a stand, i.e. the frame has to bear weight down on the axle as it would whilst riding, otherwise a jolt whilst riding will likely move the axle slightly and tension will be lost. I find it a PITA trying to secure hub gear wheels with the bike standing up, making sure alignment and chain tension is correct. . . it's fiddly.

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    I had the same thought about the shifter and tried it without touching it but it didn't help. I can't go a block before it slips. I'll check out the SA Facebook page. Thanks everyone, I guess it is just another manufacturer with no sense of decency. I'll never get another product from Sturmey Archer.

  13. #13
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by crackerdog View Post
    I had the same thought about the shifter and tried it without touching it but it didn't help. I can't go a block before it slips. I'll check out the SA Facebook page. Thanks everyone, I guess it is just another manufacturer with no sense of decency. I'll never get another product from Sturmey Archer.
    Oh come on. Apparently there was a change of ownership at Sturmey Archer and this hub was the worst of the old lot. Also, I hate to say it, but what do you expect from a discount bike like a Downtube? They have lots of little problems and reject hubs is just one of them (is there any other brand of bike which was equipped with this particular model of hub?). Also, while I'm sorry yours is bad, from the responses in this thread it seems most are not like yours.

    I'm also pretty sure that the Mini does not have a unified rear triangle. If true then I'd say the problem is the Downtube frame more than the hub (although the sensitivity of this particular hub doesn't help). If you lock out the suspension as some have done then I bet the hub will improve a lot.

    Quote Originally Posted by chagzuki View Post
    About axle slippage (apologies if this is patronizingly obvious): When I got back into cycling a few years back Datako on the Dahon forums explained to me that I ought to tighten both bolts simultaneously to, I guess, distribute pressure evenly. . . I can't remember if it was his advice or me just figuring out the obvious, that the hub needs to be secured whilst the bike is on the ground, not suspended from a stand, i.e. the frame has to bear weight down on the axle as it would whilst riding, otherwise a jolt whilst riding will likely move the axle slightly and tension will be lost. I find it a PITA trying to secure hub gear wheels with the bike standing up, making sure alignment and chain tension is correct. . . it's fiddly.
    +1 Good advice. Chain tug helps with the fiddlyness.
    Last edited by chucky; 03-31-11 at 01:30 AM.
    A sure sign of a successful experiment is when failure is prolonged until the experimenter forgets that he's even conducting an experiment.

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    Good idea about the suspension, I'll try that. I've already taken the spring out and put in hard rubber but I'll put in some hard plastic to lock it in place, don't like the bouncy feeling anyway. I will also get someone to sit on the bike when I tighten the axle. My disappointment level is extremely high so maybe I was over the top with never buying a product from SA again but it would have to have overwhelmingly good reviews. So you think Downtube is able to buy reject hubs from SA? That would make SA suck even more in my opinion.

  15. #15
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by crackerdog View Post
    Good idea about the suspension, I'll try that. I've already taken the spring out and put in hard rubber but I'll put in some hard plastic to lock it in place, don't like the bouncy feeling anyway. I will also get someone to sit on the bike when I tighten the axle. My disappointment level is extremely high so maybe I was over the top with never buying a product from SA again but it would have to have overwhelmingly good reviews. So you think Downtube is able to buy reject hubs from SA? That would make SA suck even more in my opinion.
    The first design of this hub wasn't the best. IIRC it was designed by the old ownership, but not manufactured until new ownership took over.

    After that I suspect the story went something like this: When new ownership saw the product wasn't up to snuff, they put the "slightly imperfect" stock on clearance and Downtube snapped them up at a deep discount...knowing the hubs had problems. I don't think Sturmey tried to hide the fact that this particular batch of hubs had issues...just that Downtube didn't care because their selling point is low cost (not necessarily high quality). That's why no other folding bike OEMs used this hub, even though it was specifically designed for folders, because Sturmey was honest about the issues and the only buyer that still wanted the hubs was Downtube.

    Notice that Downtube isn't offering bikes with internal hubs anymore. I think now that Sturmey fixed the design and cleared out the imperfect stock Downtube isn't interested because the price of non-imperfect hubs is too high. So as I see it, Sturmey Archer isn't at fault here; They simply gave Downtube what Downtube wanted.

    That being said, IMO this hub is only slightly more problematic than the Alfine (ie not outright "defective" at all) and I think most of the complaints about this hub have been misguided/misunderstood due to the fact that half the hubs out there were equipped on bikes with nonunified rear triangles (ie the Downtube Mini). IGHs are not compatible with non-unified rear triangle suspension systems. I know a guy who tried putting an Alfine on a non-URT suspension frame (not the Mini) and it was even worse than the XRF8.

    You see, the problem is that a non-URT suspension alters chain tension during operation. So unless you're using a spring loaded tensioner (ie like a derailleur) the chain will keep tugging HARD on the axle (which is actually one of the internal gears in an IGH)...it's like riding with a monkey on your rack trained to continually smack the hub with a hammer. It also tugs on the gear cable and while a properly routed cable should ideally be able to take some tugging, the cabling on folders is often less than ideal and IGHs are also often less tolerant of cable misadjustment (not to mention the question of whether or not the cables are properly routed). Combine this with a hub which already has some minor issues and you have a recipe for disaster.
    Last edited by chucky; 04-02-11 at 05:09 PM.
    A sure sign of a successful experiment is when failure is prolonged until the experimenter forgets that he's even conducting an experiment.

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    Thank you, thank you, thank you! The non-unified frame point seems to have been the problem. I couldn't find any hard plastic yet but I found some REALLY hard rubber that I fashioned to replace the softer rubber bumpers that I had replaced the original spring with. I tightened it as tight as I could to make it stiff. It shifts perfectly without skipping at all. Completely solved the problem. I also took apart the hub a little bit just to see how that works. I ran into a problem reassembling it because the SA instructions are wrong but luckily some folks on Bike Forums have the correct instructions and it went back together fine the second time. I am back to loving my folder. Off to pootle around some more. Thanks again everyone.

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    Eschew Obfuscation SesameCrunch's Avatar
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    Quote Originally Posted by chucky View Post
    After that I suspect the story went something like this: When new ownership saw the product wasn't up to snuff, they put the "slightly imperfect" stock on clearance and Downtube snapped them up at a deep discount...knowing the hubs had problems. I don't think Sturmey tried to hide the fact that this particular batch of hubs had issues...just that Downtube didn't care because their selling point is low cost (not necessarily high quality). That's why no other folding bike OEMs used this hub, even though it was specifically designed for folders, because Sturmey was honest about the issues and the only buyer that still wanted the hubs was Downtube.
    Geez, this kind of public accusation, without any basis in fact, could get you sued....

    Yan may have sought to create a niche for a low cost, entry level product line, but one would have to be stupid to buy known defective product to create a brand identity. Yan is not stupid.
    Last edited by SesameCrunch; 04-03-11 at 07:48 PM.

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    BikingYupik BikeKraft's Avatar
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    Chunky did say "I suspect". I like to speculate too, it's a weakness.
    I like my Downtube with the SA hub.
    a driver's test is not an IQ test

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    BikingYupik BikeKraft's Avatar
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    I mean Chucky, my wife is pressuring me to get up stairs!
    a driver's test is not an IQ test

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    Now that the hub is working well, I am very pleased with Downtube Mini quality. I never thought it would be a high end bike but it is better than I thought it would be for the price. I got the Mini for my first folder and for riding the bus when I need to which isn't all that often because I live in a small town. I also use it when someone visits because it fits almost anyone. A friend came to visit on the ferry and I took my Xtracycle with the Mini in the pannier. I carried the luggage on the Xtra and he rode the Mini to my house.

  21. #21
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by SesameCrunch View Post
    Geez, this kind of public accusation, without any basis in fact, could get you sued....

    Yan may have sought to create a niche for a low cost, entry level product line, but one would have to be stupid to buy known defective product to create a brand identity. Yan is not stupid.
    Meanwhile, thanks to my keen observations, crackerdog's bike works.

    It's a beautiful thing how the internet allows truth and knowledge to reign, unfettered by blood sucking lawyers and the incompetent morons who must resort to hiring them. Thank God for the immunity of anonymity, for without it, by now society as we know it would surely have strangled itself to death in its own bureaucratic red tape.

    But who said anything about a "defective product"? Despite what the lawyers and marketers would have us believe, the fact is there are many shades of gray between ideal operation and outright defect. I love my Downtube, but that doesn't mean it couldn't have been better made (there's always room for improvement).

    Quote Originally Posted by BikeKraft View Post
    I like to speculate too, it's a weakness.
    Weakness? Hurray for speculation; It is the father of knowledge. Especially when done transparently in an open forum.
    Last edited by chucky; 04-04-11 at 02:29 AM.
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    tcs
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    Quote Originally Posted by chucky View Post
    IGHs are not compatible with non-unified rear triangle suspension systems.
    Dr. Alex Moulton, call your office!
    "When man first set woman on two wheels with a pair of pedals, did he know, I wonder, that he had rent the veil of the harem in twain? A woman on a bicycle has all the world before her where to choose; she can go where she will, no man hindering." The Typewriter Girl, 1899.

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    Quote Originally Posted by crackerdog View Post
    I've tried to read through the archives but does anyone know what the final verdict was on dealing with the cursed SA X-RF8 hub that keeps slipping? Did Sturmey Archer and Downtube just screw everyone with that hub or is there a fix?
    Yes, yes, the archives are fine and all but I wonder if you could relate the results of your correspondence with the companies involved? Perhaps you could share your phone calls and emails to Downtube and Sturmey, and results of same?
    "When man first set woman on two wheels with a pair of pedals, did he know, I wonder, that he had rent the veil of the harem in twain? A woman on a bicycle has all the world before her where to choose; she can go where she will, no man hindering." The Typewriter Girl, 1899.

    "Every so often a bird gets up and flies some place it's drawn to. I don't suppose it could tell you why, but it does it anyway." Ian Hibell, 1934-2008

  24. #24
    Eschew Obfuscation SesameCrunch's Avatar
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    Quote Originally Posted by chucky View Post
    It's a beautiful thing how the internet allows truth and knowledge to reign, unfettered by blood sucking lawyers and the incompetent morons who must resort to hiring them.
    What's your definition of truth?

    Chucky's clairovyant conspiracy theories?

  25. #25
    It's got electrolytes! chucky's Avatar
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    Quote Originally Posted by SesameCrunch View Post
    What's your definition of truth?

    Chucky's clairovyant conspiracy theories?
    That's just the thing. In a court of law it's essentially what would convince the average person, but since the average person is a moron, I subscribe to the much more reliable and useful definition of truth which is those statements which are most likely to agree with future/unseen/yet-to-be-revealed observations.

    So on the one hand you have speculation and on the other you have concrete observation. Many people might argue that concrete observation constitutes the truth by itself, but they would be wrong because subsequent observations ("verifications", "checks", etc) will rarely be exactly the same. So the truth always lies somewhere between the two (ie between "clairovyant conspiracy theories" and concrete observation) and it is only by engaging both that knowledge is created (ie truth is correctly ascertained).

    Take, for example, our little discussion above. "The facts" seemed to indicate that there was something wrong with crackerdog's hub, but speculation suggested that it was the setup. It should be no surprise that the truth, which reality subsequently bore out, was somewhere between the two (after all, there's an exact science to this...I'm not pulling it out of my ass).

    Once again, I think the fact that crackdog's bike now works should be quite telling of which one of us is winning this argument...regardless of how much it offends your sense of rationale, the rationale of the average man, or even the law.

    Quote Originally Posted by tcs View Post
    Dr. Alex Moulton, call your office!
    Do you have any pictures of this? Alex Moulton's designs are unique in that they tend to be executed correctly.
    Last edited by chucky; 04-04-11 at 12:10 PM.
    A sure sign of a successful experiment is when failure is prolonged until the experimenter forgets that he's even conducting an experiment.

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