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  1. #1
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    Fatbike design and evolutionary changes needed...

    I'm eagerly anticipating the On-One fatbike because it seems to be close to what I want. That On-One are promoting it as a rock-crawler is a plus.

    But it has prompted some idle thoughts about some things that could be improved on fatbikes.

    1. Fork ends: there is so much grip in a fat tyre that forkends that were evolved to deal with skinny tyres are not really suitable. The extra grip is twisting the forks. I think we need a move to through axles to unify the structure more. This need will become more apparent as fatbikes get used more on hard surface trails.

    2. Geometry: my experiments with steeper head angles while preserving a reasonable trail have me convinced that this is the way to go. This also means the head of the bike is raised or lowered less during low speed turning which may be of some advantage in snow - I haven't tested that. A nimble bike is always an advantage at the low speeds used in lumpy ground.

    3. Front dropout widths: we are now getting tyres that are fatter than the usual 100mm OLD on the front. The easy cure is to go to 135mm and use a rear hub or special front depending on the fork. My limited experience with 135mm front OLDs (Surly offset fork, Salsa Enabler) is that there is a fair bit of squirming going on when the brakes are used heavily (hence point 1). At the moment it's possible to squeeze the fatter tyres into a 100mm fork, but maybe we need a front new standard such as 110mm or 120mm. Short as possible being the better to reduce potential for flex.

    4: Rear dropout width: Currently the offset 135 is the most useful setup, but this creates potential problems with wheel builds. Unfortunately once we go for a symmetrical wheel build we lose the ability to use hub gears. I suspect that changes here have to come from the hubgear manufacturers rather than the frame builders. The only 170mm hubgear is the S-A and with only 3 speeds it is too limited a range for most people.

    5. Tyre widths: I'm convinced that a minimum of 6" is necessary for real progress in soft going.

    6. Suspension: As tyres get fatter, pressures have to drop and then we get the inevitable pedal bob. Combine a fat tyre with suspension and you have some interesting dynamics. Suspension damping combined with lower profile tyres may become necessary so that most of the suspension movement is in portion of travel controlled by the damper. I'm sure once the downhill boys wake up to the grip advantages of fat tyres we'll see some rapid advances in this area.
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  2. #2
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    I have not noticed fork/hub twisting. A fork with forward opening dropouts negates hub movement under braking, especially when used with a good internal cam QR skewer (Shimano).
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  3. #3
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    In my opinion, the offset rear is not a good design. Having the wheel/hub centered under you is important...despite what has been debated over and over. Offsets are fine for dirt or snowmobile trails, but if you are in tough snow conditions, handling suffers...especially when you come over-center with your weight. Just my experience....that is why I got rid of my pug and bought a fatback.

  4. #4
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    Quote Originally Posted by sevenpedaler View Post
    In my opinion, the offset rear is not a good design. Having the wheel/hub centered under you is important...despite what has been debated over and over. Offsets are fine for dirt or snowmobile trails, but if you are in tough snow conditions, handling suffers...especially when you come over-center with your weight. Just my experience....that is why I got rid of my pug and bought a fatback.
    A far as weight distribution goes, having the tire contact patch on the centerline of the BB/steer tube/rider is what matters. That can happen with an offset frame/fork (and does with the Pugs) or a symmetrical frame/fork.
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  5. #5
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    Quote Originally Posted by shiggy View Post
    I have not noticed fork/hub twisting. A fork with forward opening dropouts negates hub movement under braking, especially when used with a good internal cam QR skewer (Shimano).
    I think relying on a 9mm or 10mm QR axle is asking a lot considering it was designed for much lighter use. I'm convinced what I'm feeling is down to the axle being inadequate for the loads under heavy braking. I noticed it immediately when I put on the Enabler, and to a lesser extent with the Pug offset 135mm fork. The squirming effect was much less with my 100mm OLD forks. (I'm not talking about axles being popped out of dropouts but flex). We're putting motorcycle level grip loads through an assembly designed for a 1900s gentleman's bicycle.

    Quote Originally Posted by sevenpedaler View Post
    In my opinion, the offset rear is not a good design. Having the wheel/hub centered under you is important...despite what has been debated over and over...
    The point of the offset is to allow you to use a 135mm hub. Its offset matches that of the frame so that the wheel does align with the centreline of the bike, ie centred under you. Thus it should have no negative effect on handling. Until we get wider gearhubs, it's the best solution available.
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  6. #6
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    Quote Originally Posted by Velobike View Post
    I think relying on a 9mm or 10mm QR axle is asking a lot considering it was designed for much lighter use. I'm convinced what I'm feeling is down to the axle being inadequate for the loads under heavy braking. I noticed it immediately when I put on the Enabler, and to a lesser extent with the Pug offset 135mm fork. The squirming effect was much less with my 100mm OLD forks. (I'm not talking about axles being popped out of dropouts but flex). We're putting motorcycle level grip loads through an assembly designed for a 1900s gentleman's bicycle.
    I started out with the Hadley QR's that came with the hubs, but they couldn't keep the wheels in place for trail riding. I kept having disc rub problems, realized I could fix them by opening the QR and letting the wheel drop back into place. Hadley QR's are external cam, and seem to have a narrower cam than some. I replaced the front with a shimano internal cam QR and stopped having issues. The back is now a bolt-on, and stays put as well. I think that thru axle hubs would be a good feature for fatbikes, especially as they move into suspension and higher loads/speeds.

    Quote Originally Posted by sevenpedaler View Post
    In my opinion, the offset rear is not a good design. Having the wheel/hub centered under you is important...despite what has been debated over and over. Offsets are fine for dirt or snowmobile trails, but if you are in tough snow conditions, handling suffers...especially when you come over-center with your weight. Just my experience....that is why I got rid of my pug and bought a fatback.
    As long as the forces remain centered and symmetrical, there is no issue. If you have an offset build and the wheel or frame is flexing out of line, then you will have issues because the forces will no longer be in line.

    Symmetry is overrated.
    Attached Thumbnails Attached Thumbnails Fatbike design and evolutionary changes needed...-img_1792s.jpg  

    This isn't a "you're doing it wrong" topic.

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  7. #7
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    VB: like your thoughts.

    #1 Fork ends - would never consider nothing less that a 20mm through axle
    for a custom fork

    #2 Geo - My current thinking is 71.5* with a A/C of about 425mm and offset of 45,
    gives somewhere in the area of 75mm trail, if I remember correctly. What is your
    thinking about what would be ideal?

    #3 Front Dropout width - If you plan for those 6" tires seems like you would need
    something like 170mm width? Am I right in thinking that forks this wide would tend
    to flex more easily? Perhaps with a 20mm TA or larger combined with an short A/C
    with heavier gauged tubing and shaped legs, flex could be managed? Is not fork flex
    less needful in a fat bike fork for comfort anyway, so why not take advantage of the
    tire cush and make a trade?

    #6 Suspension - Baloons for tires and a suspension fork make for some interesting
    choices. Seems like your idea of low profile tires must be the path for the future if
    wider tires are to be produced.

    Standover Height - One of my personal quibs with fatbikes, it is higher than needed with
    any frame size. Again shorten that A/C measurement AND run that top tube through a split
    down tube, each would connect to the headtube in the reverse present pattern.

    Why, since all fatbikes presently produced are full rigid, why the long A/C as in a suspension
    fork? Sure, some have stuck on a suspension fork and are happy with it, and the frame design
    easily accomedates this move. However, if frames were designed with a low BB height and
    steeper headtube angles, and then if someone wished to add a suspension fork, would this not
    then move the effective BB height and headtube angle into an acceptable range for the intended
    purpose?

    With proper planning of construction, could we not then get a little more of having our cake and
    eating it too?

  8. #8
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    Given my experiment with a 69 degree head angle with a suspension corrected rigid fork, and then an unknown degree head angle with a Lefty, I'm going to agree that a slightly steeper angle is good for fatties.

    That said, if you steepen to an extreme, suspension fork legs tend to bind more, don't they? I'm no expert here so I'm asking more than stating. I like the idea of a 3.5" linkage fork for fat tires - put some condoms around the pivots and enjoy some long lasting function in mucky / cold conditions.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  9. #9
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    Quote Originally Posted by Velobike View Post
    I'm eagerly anticipating the On-One fatbike because it seems to be close to what I want. That On-One are promoting it as a rock-crawler is a plus.

    But it has prompted some idle thoughts about some things that could be improved on fatbikes.

    1. Fork ends: there is so much grip in a fat tyre that forkends that were evolved to deal with skinny tyres are not really suitable. The extra grip is twisting the forks. I think we need a move to through axles to unify the structure more. This need will become more apparent as fatbikes get used more on hard surface trails.

    2. Geometry: my experiments with steeper head angles while preserving a reasonable trail have me convinced that this is the way to go. This also means the head of the bike is raised or lowered less during low speed turning which may be of some advantage in snow - I haven't tested that. A nimble bike is always an advantage at the low speeds used in lumpy ground.

    3. Front dropout widths: we are now getting tyres that are fatter than the usual 100mm OLD on the front. The easy cure is to go to 135mm and use a rear hub or special front depending on the fork. My limited experience with 135mm front OLDs (Surly offset fork, Salsa Enabler) is that there is a fair bit of squirming going on when the brakes are used heavily (hence point 1). At the moment it's possible to squeeze the fatter tyres into a 100mm fork, but maybe we need a front new standard such as 110mm or 120mm. Short as possible being the better to reduce potential for flex.

    4: Rear dropout width: Currently the offset 135 is the most useful setup, but this creates potential problems with wheel builds. Unfortunately once we go for a symmetrical wheel build we lose the ability to use hub gears. I suspect that changes here have to come from the hubgear manufacturers rather than the frame builders. The only 170mm hubgear is the S-A and with only 3 speeds it is too limited a range for most people.

    5. Tyre widths: I'm convinced that a minimum of 6" is necessary for real progress in soft going.

    6. Suspension: As tyres get fatter, pressures have to drop and then we get the inevitable pedal bob. Combine a fat tyre with suspension and you have some interesting dynamics. Suspension damping combined with lower profile tyres may become necessary so that most of the suspension movement is in portion of travel controlled by the damper. I'm sure once the downhill boys wake up to the grip advantages of fat tyres we'll see some rapid advances in this area.


    1. Funny. You are the only person to ever suggest this. I see no issue what so ever. Thru axel unnecessary.

    2. Steeper head angle. I'll disagree again with this. I'd even suggest slacker.

    3.135mm works fine. No new standards when you don't need them. And its' a pain in the ass for everyone from fork makers, brake makers, and hub makers. 135mm works just fine.

    4. Agree, but mostly disagree. Loss of gears? Tell that to the Pugsley. Or my 9:Zero:7 offset which works great as is...I could run gears up front no problem, but choose not too. Tell that to Moonlander. Some sacrifice...but not much.

    I only agree because as I'm looking to experiment with things like 38mm wide 29er rims in the rear, 47mm 26" rims, etc.. they don't like the offset. Which sucks. Because I don't like 170mm hubs...but I see the point now. Next bike probably will just because I like to tinker. But my favorite hubs won't be 170mm anytime soon either so we'll see. Rims however...

    5. 6" will be fun, but for a select niche of terrain. Think we'll see a front for sure. Hell I'll want one for fun. But haven't found a need for wider than my 3.8's I'm running now. Plus in rear you'll have to go long chain stays or a jackshaft...neither is a good idea. If you really want bigger...just do it right and go Hannebrink. Works awesome and great company. Bonus: You have an electric option that is best in that field. Seriously. Give Kane a call. Great guy.

    6. DH? They actually went the other way...used to have a few 3.0 tires (which were the early fat bike tire pre-Surly Pugsley world) and such. Yet guess what? Some run as small as a 2.35". Why? Every second counts. Same reason a 29er DH may exist, but no one is placing on one.

    Suspension: Will agree. Wrote a bit on Fat-bike.com (Write there as "Sevo")on the very issue that we'll see tire size decrease to 3.2-3.3" area on narrower rims when suspension comes around. Low profile I agree will be a must. Larger tires however will be counterproductive.

    Even with smaller tires with low profiles we'll have a whole new slew of problems arise. Which once again will point towards smaller tires.

    Do agree that Shiggy's rig is probably where we'll see a lot of people going. The general public can't convince their significant other they have a bike that is only good for snow and sand, which means they'll start setting 'em for year round use. Which is another reason you'll start seeing some narrower tire options.
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  10. #10
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    there really is no downside to a thru axle or 360 dropout besides weight and cost... seeing as we are talking aboot $2000 30lb bikes, i think that is a non issue.

    as for the new standard of front hubs, i never support new standards in the bike industry unless it is a huge improvement. please don't encourage these kind of cash grabs.

    side note, i have a BFL on a RD in my 100mm fork. all i have to do is remove my caliper (but i'm used to that coming from my lefty) clownshoe fits through the dropout, but i would have to deflate the tire and would require more clearance than my pugs fork could handle. easily fixable but a bit of a nuisance
    your 29er may float over roots and rocks, but my superlight 26 just plain floats

  11. #11
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    Quote Originally Posted by juansevo View Post
    1. Funny. You are the only person to ever suggest this. I see no issue what so ever. Thru axel unnecessary.
    2. Steeper head angle. I'll disagree again with this. I'd even suggest slacker.
    3.135mm works fine. No new standards when you don't need them. And its' a pain in the ass for everyone from fork makers, brake makers, and hub makers. 135mm works just fine.

    5. 6" will be fun, but for a select niche of terrain. Think we'll see a front for sure. Hell I'll want one for fun. But haven't found a need for wider than my 3.8's I'm running now. Plus in rear you'll have to go long chain stays or a jackshaft...neither is a good idea. If you really want bigger...just do it right and go Hannebrink...
    1. Maybe I'm the only person who's tried 5 different forks on the same afternoon.

    2. My preference for steep HAs is a result of experimentation - with rigid forks. Agree that slack HAs are required to allow a telescopic fork to work properly - they stutter with a steep HA. It's about time we had a decent linkage fork.

    3. I'd be perfectly happy with a 135mmm through axle front hub, but narrower would be lighter and stiffer.

    5. I want to ride on a select niche of terrain. That's the point of a fatbike surely. Plenty peat bogs around where I live. The Hannebrink looks like a bodge made up of available parts rather than an evolved product. I've done enough riding on small wheels offroad to have serious doubts about small wheels capacity to keep going when faced with large obstacles.
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  12. #12
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    VB has obviously been thinking and experimenting with these ideas for some time.
    As a 260lbs+ rider, I agree that front through axle forks are stiffer and prevent Qr/dropout issues.

    I do not ride front QR forks off road at all now.

    Rear frame width would probably be best at 170 OLD . It does give the possibility for symmetrical builds and (potentially) 170mm IGH hubs with LOTS of gears.
    Would be best to have bolt through axle as well or Maxel type set up.

    Until then an offset adapter would be appreciated

    VB makes an excellent point about low profile rubber. This is exactly what has happened in cars with wide rubber and low height ratios. There would of course need to be wider (TA) suspension forks

    Geometry , I will not comment on as I generally prefer slack
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    When I9, Hope or Hadley make a 170 hub with high engagement points, I would consider a symmetrical frame, otherwise I personally see no need to switch from my Pugsley. Geometry is a personal thing- I would hate to see all fat bikes follow the same standard, because they are all ridden in different conditions and terrain.

  14. #14
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    Quote Originally Posted by Dr Feelygood ! View Post
    ...Geometry , I will not comment on as I generally prefer slack
    I can understand that. A slack HA with a long travel telescopic fork becomes very steep under heavy braking, so slackness is necessary with a telescopic fork to allow for this (as well as function).

    A steep HA frame requires either a rigid fork, or a linkage fork with compensating linkages.
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    Tyres...

    I often think about them.

    I've lived with tyres for all purposes, I feel people will be making a mistake should they think "Fatter is better" In actual fact, for our fatties, 4" is about right. Why, because the forward resistance it causes is negligable, i.e. it pushes very little wave in front of it at the front contact point. Going to 6" wide increases this forwad contact wave or resistance. Now, having said that, I too, would like more floatation, how is this achieved? Simple, larger diameter, by doing this, one creates a bigger foot print when the tyre is deflated. Remember, a tyres width is fixed, the length of it's foot print however, is only limited by its side wall height and diameter. So if we had a 4" tyre with a 4" side wall that was 32 inches in diameter we could let it down to say 4 / 5 PSI and get a foot print that was say, 14 inches long by 4 inches wide, this would give us 56 square inches per wheel of ground contact space and only be displacing 4" of snow / mud at it's front contact point. Now lets say my bike and I have a combined weight of 230 Lbs and we assume 75% rear and 25% front load share. (This is just a guess BTW !) The back wheel will be carrying 172.5 Lbs and the front 57.5 Lbs it'll mean the rear has a ground contact loading of 3.08 Lbs per square inch and the front 1.02 Lbs per square inches. Make sense?

    On hard track or asphalt, wider, lower profile is better,particularly when coupled to high horsepower and torque, but that's a whole story of its own!!!

    Have a think about snow skies as opposed to snow shoes...........

    Comments?????

  16. #16
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    Quote Originally Posted by alanm View Post
    ...I too, would like more floatation, how is this achieved? Simple, larger diameter, by doing this, one creates a bigger foot print when the tyre is deflated....
    I agree.

    That's another valid way to get what I'd like - more flotation. The larger diameter would have benefits in the rolling resistance too.

    There would be construction difficulties - such as how to fit the rest of the bike between the wheels.

    However there is already a 36" wheel bike getting around, so nothing impossible there. It would also mean that problems with chainline on extra wide tyres would be obviated.



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  17. #17
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    HArdest ride on my fat

    Quote Originally Posted by Velobike View Post
    I'm eagerly anticipating the On-One fatbike because it seems to be close to what I want. That On-One are promoting it as a rock-crawler is a plus.

    But it has prompted some idle thoughts about some things that could be improved on fatbikes.

    .....

    2. Geometry: my experiments with steeper head angles while preserving a reasonable trail have me convinced that this is the way to go. This also means the head of the bike is raised or lowered less during low speed turning which may be of some advantage in snow - I haven't tested that. A nimble bike is always an advantage at the low speeds used in lumpy ground.
    ......
    For those that need to tweak HA:

    Cane Creek Cycling Components :: Components :: Headsets

    My new Fatback has the slackest HA of any bike I've own. So far in both sand and snow it works better than anything I've tried. Descending is fantastic. I've never ridden one, but I know a couple of guys who years back purchased a crossbike with a seriously steep HA and they could not control them in sand.

    "Low speed, lumpy ground" - Glad I read this, trying to decide where to ride today, now I know where to go, and see how the Fatback handles a really ugly section of trail - sharp LH turn on a steep hump. I'll answer back on this one later.

  18. #18
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    Quote Originally Posted by Steve Balogh View Post
    ..."Low speed, lumpy ground" - Glad I read this, trying to decide where to ride today, now I know where to go, and see how the Fatback handles a really ugly section of trail - sharp LH turn on a steep hump. I'll answer back on this one later.
    I'll be interested in your findings.

    On the 24 hour I did recently the Pugsley was quite tricky and didn't handle as well as one of my bikes bike with the steeper head angle on the same sections.

    Of course, HA isn't all there is to this. The HA and the offset combine to determine the trail and there's various combinations that will result in the same trail figure. For a given trail figure I prefer the steeper HA.

    On the other hand, I've heard there have been some papers that claim that none of this really matters and we humans simply adapt to what we are riding. (I don't have a reference unfortunately - maybe someone can point to it).
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  19. #19
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    Quote Originally Posted by deuxdiesel View Post
    When I9, Hope or Hadley make a 170 hub with high engagement points, I would consider a symmetrical frame, otherwise I personally see no need to switch from my Pugsley. Geometry is a personal thing- I would hate to see all fat bikes follow the same standard, because they are all ridden in different conditions and terrain.


    Hadley do make a 170 hub. The US Fatback hubs have been made by Hadley, exclusively for Fatback, from the get-go.

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    Also, Paul is supposed to be eventually making a 170 rear hub that will be using I9 freehubs.

  21. #21
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    Quote Originally Posted by Velobike View Post
    On the other hand, I've heard there have been some papers that claim that none of this really matters and we humans simply adapt to what we are riding. (I don't have a reference unfortunately - maybe someone can point to it).
    Just look up "unrideable bicycle"
    The stability of the bicycle

    I first read this in "Bicycling Science" by DG Wilson. There is a lot of information in there, and some mathematical models of handling/stability. I took what I recall was the "stability number" equation, and graphed it - trail vs head angle. an 80 degree head angle always required the least trail to achieve the same stability number. Recumbents I built with this head angle worked very well - but I found I needed to run narrow handlebars so the force/feedback felt right.

    A better system of analysis was Bill Patterson's "Lords of the chainring" class materials from CalPolyTech. The math was simplified from the models used for aircraft. Calculations require knowing the center of gravity of the bike as well as the radius of the tire profile - among other factors. He doesn't give you a perfect number to work to, but the system lets you compare things and decide what range of values you like.

    Most modern bikes are just "rule of thumb" cut/try, but they do work. But look at how 29ers had to evolve their own "rules" - and we're doing the same now for fatties.
    This isn't a "you're doing it wrong" topic.

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  22. #22
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    Today's ride

    Quote Originally Posted by Velobike View Post
    I'll be interested in your findings.

    On the 24 hour I did recently the Pugsley was quite tricky and didn't handle as well as one of my bikes bike with the steeper head angle on the same sections.

    Of course, HA isn't all there is to this. The HA and the offset combine to determine the trail and there's various combinations that will result in the same trail figure. For a given trail figure I prefer the steeper HA.

    On the other hand, I've heard there have been some papers that claim that none of this really matters and we humans simply adapt to what we are riding. (I don't have a reference unfortunately - maybe someone can point to it).
    OK, tried a couple of trails today:

    The one hump I spoke of, the Fatback cut through it like a hot knife through butter. Some other sections that have small steep hills with almost total switchback turns, I could cut the corners better than any bike I've owned. Same story with a second trail I rode today, the odd weather we had unfortunately attracted "pizza cutter" riders who took to the mid-winter thaw and really hacked up several trails - today those frozen ruts created a ton of stutter bumps on many climbs and descents. All worked well on the Fatback.

    I find this interesting what you are saying because a couple of friends of mine bought a once popular cyclocross bike that had a steep HA. Wasn't long before they sold them. When riding them through sand they were difficult to control. But I'm thinking why the MFG did that might be related to what you are saying.

    I seriously made an effort to make my Fatback fail, but nothing worked. Perhaps the terrain you ride is way different from mine. The only other place I could possible test your idea here is a vacant field near my house, extremely bumpy, and requires riding through thick field grass as well.

    When Greg set me up the frame, he made a last minute decision to put me in a bigger frame, I'm using a 20 instead of an 18, with a 110 stem and a Moots bar with an 8-degree sweep. This is the largest frame I've ever owned, I've taken to it quite quickly. I have a short inseam, but a long torso. The bend in the top tube and the slack HA is what makes this frame work for me.

  23. #23
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    Quote Originally Posted by wadester View Post
    Just look up "unrideable bicycle"
    The stability of the bicycle...
    I'm familiar with that one. Also Wilson, Sharpe and others. My favourite was the work of Tony Foale - unfortunately I loaned his book out many years ago and never got it back.

    I gave up on trying calculations and moved to an empirical method - there's too many variables for me to digitally calculate even if I take my shoes off for larger numbers (even in binary ), so an adjustment of a few degrees here and a inch or so there is the way I work now.

    Weight distribution is important too. The large variation in tyre profiles available of a fatbike throw a bit of randomness into the mix too. Then there's the profile problem - the shape of the same tyre on a 100mm rim and low pressure is widely different from it on a narrow rim and a slightly higher pressure.
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    Quote Originally Posted by shiggy View Post
    I have not noticed fork/hub twisting. A fork with forward opening dropouts negates hub movement under braking, especially when used with a good internal cam QR skewer (Shimano).
    I hate to say that I have noticed some twisting in the fork of my Mukluk under hard braking and I'd likely attribute it to twist in the hub/fork juncture. I switched from the stock skewer and it definitely helped, but even before I read this post, on my ride yesterday I had an instance going into a dirt corner hard under braking where I got a good bit of flex... enough to make me think about it. And this wasn't on a steep or rocky trail. Just a level trail on good, tacky, Midwestern dirt. In fact, attached is a photo from the ride...
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    Quote Originally Posted by Velobike View Post
    I'll be interested in your findings.

    On the 24 hour I did recently the Pugsley was quite tricky and didn't handle as well as one of my bikes bike with the steeper head angle on the same sections.

    Of course, HA isn't all there is to this. The HA and the offset combine to determine the trail and there's various combinations that will result in the same trail figure. For a given trail figure I prefer the steeper HA..

    Anyone have input about good range of fork trail to use for fattbikes? Looks like a pugsly uses about 82mm and 907 about 85mm. Any thought about effect of trail above/below this range?
    I threw together a random collection of parts and had >110mm of trail. It was way,way too much and had horrible wheel flop and very quirky, unpredictable steering. I re-worked the bike for 90mm of trail (71degree HTA) and it is much better now. Just wonder how a much lower trail figure like 60-70mm might feel on a fatbike.

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    Quote Originally Posted by mgersib View Post
    I hate to say that I have noticed some twisting in the fork of my Mukluk under hard braking and I'd likely attribute it to twist in the hub/fork juncture. I switched from the stock skewer and it definitely helped, but even before I read this post, on my ride yesterday I had an instance going into a dirt corner hard under braking where I got a good bit of flex... enough to make me think about it. And this wasn't on a steep or rocky trail. Just a level trail on good, tacky, Midwestern dirt. In fact, attached is a photo from the ride...
    I wonder if it more about the torsional stiffness of the fork rather than the fork/hub interface since the forks are WAY wider. It is one of the things I thought about when I drew up the fork for the On-One fat bike (that now rusty one). I was surprised about how light the unicorn fork I am using is.
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    Quote Originally Posted by shiggy View Post
    I wonder if it more about the torsional stiffness of the fork rather than the fork/hub interface since the forks are WAY wider. It is one of the things I thought about when I drew up the fork for the On-One fat bike (that now rusty one). I was surprised about how light the unicorn fork I am using is.
    I suspect it's a combination of forces. I notice it most on the Enabler which is a symmetrical 135mm fork, and to a lesser extent on the 135mm offset Surly fork.

    A large diameter through axle clamped in the fork legs is going to have 2 benefits, firstly to eliminate any axle flex, and secondly as a result of the clamping to stiffen up the fork.
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    Interesting thoughts VB.

    I'd say that your needs are about as niche as they come, and you'd be best served (on most of them) by simply going custom, instead of asking the industry to adapt to your whims.

    Nothing wrong with your whims, but even you can see that they go against the grain of what most are using and asking for.

    Like yours, my whims are non-standard in many ways. I've asked some of the biggies to consider my preferences in the past, and then, after I got the idea that they had no interest, I just went custom. Works for me.

    YMMV.

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    Well;

    I think the front thru axle idea is particularly keen. For all the reasons stated, it seems to me to be a natural. If many if not most 2-9ers are going that way... is it not a Fatbike natural? Once someone makes a real suspension fork, it would seem to be almost obvious. Shouldn't be very hard to accomplish at all in the time being on any given CroMo fork.

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    Quote Originally Posted by shiggy View Post
    I wonder if it more about the torsional stiffness of the fork rather than the fork/hub interface since the forks are WAY wider. It is one of the things I thought about when I drew up the fork for the On-One fat bike (that now rusty one). I was surprised about how light the unicorn fork I am using is.
    Yeah... I wonder what a QR15 interface would feel like. I bet that change alone, with the same fork legs, would get us the necessary stiffness. The reason I believe it's the hub/dropout interface is because there have been two instances where, after either going through a cross-rut, or making an aggressive move with the bars, I have actually had the hub move slightly in the dropouts. It was the initial reason for my skewer switch from the stock Salsa model on the front-end of my Mukluk.

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    Quote Originally Posted by Velobike View Post
    A large diameter through axle clamped in the fork legs is going to have 2 benefits, firstly to eliminate any axle flex, and secondly as a result of the clamping to stiffen up the fork.
    #3 = Takes more time to swipe! Which is why I prefer bolt-ons.

    Less worry over safety, stronger, and more apt to stay mine.

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    Quote Originally Posted by mgersib View Post
    Yeah... I wonder what a QR15 interface would feel like. I bet that change alone, with the same fork legs, would get us the necessary stiffness. The reason I believe it's the hub/dropout interface is because there have been two instances where, after either going through a cross-rut, or making an aggressive move with the bars, I have actually had the hub move slightly in the dropouts. It was the initial reason for my skewer switch from the stock Salsa model on the front-end of my Mukluk.
    MG: I hear ya. I have felt some strange sensation in the front end of my Muk too. Even had the hub shift in the drops once. This is also on dry trail.

    Of course, we are putting a lot bigger footprint on the ground resulting in a lot more traction than our 29"ers have. Something has to give if the tire sticks better, ya know? It's like a football player on Astro-turf. The foot sticks like glue but the knee will give out when the guy gets tackled.

    You are familiar with the old, larger axle caps once tried on 26"ers. Specialized does this with their OS-28 end caps. I feel it helps a lot, and feels about the same as a 15Qr, to my mind. It could be a way to go to keep QR's and get rid of the funky feel.

    In the end, I think a thru-axle would help, but I am just suggesting that QR's may not have to go if they are used with the over-sized axle end cap concept. That said, Maxles are so easy to use, why not, right?

    As far as the rest goes, I see a bit slacker head tube angles being far better in loose stuff, and can be done to handle just great for trails. This past weekend's ride on snow really dialed me up to why slacker is better for the loose stuff.
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    Quote Originally Posted by Guitar Ted View Post
    You are familiar with the old, larger axle caps once tried on 26"ers. Specialized does this with their OS-28 end caps. I feel it helps a lot, and feels about the same as a 15Qr, to my mind. It could be a way to go to keep QR's and get rid of the funky feel.

    In the end, I think a thru-axle would help, but I am just suggesting that QR's may not have to go if they are used with the over-sized axle end cap concept. That said, Maxles are so easy to use, why not, right?
    I agree. I have front QR hubs with 25mm faces. Makes a noticeable difference in a sussy fork.
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    Quote Originally Posted by shiggy View Post
    I agree. I have front QR hubs with 25mm faces. Makes a noticeable difference in a sussy fork.
    I've been thinking while reading this thread and after years of riding Mag 21's and then 28mm Sids flex what flex? I suppose it's all relative.
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    Quote Originally Posted by mikesee View Post
    ...you'd be best served (on most of them) by simply going custom, instead of asking the industry to adapt to your whims....
    I'm not so much asking the industry to change as trying to predict the direction it will move in.

    As for custom, you're probably right. My liking for steep HAs is not going to go down well with a market that believes slacker head angles are the go - and they're right if they fit a telescopic fork. The slacker HA is needed as the travel of telescopic forks increase. Thus the benefits of a steep HA can only be got with rigid or linkage forks.

    BTW if we have the same trail figure on 2 bikes (assuming everything else on the bikes is identical), one steep, the other slack, the one with the steep HA will flop less at low speeds (think climbing on lumpy stuff) and be less inclined to get deflected by edge impacts (not so easily unsettled by ruts).

    If anyone wants a cheap way to experiment with this, just make a DIY fork which allows you to adjust various factors, and thus simulate the various HAs on a frame.
    Last edited by Velobike; 01-17-2012 at 01:37 AM.
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    I understand the effects of offset and trail very well, and I too have an adjustable offset fork to play with.

    I've experimented bunches, and my conclusion is a virtual mirror image of yours: More. As in, I always want a higher trail number than the industry is willing to offer. Anything less than 90mm and the bike feels sketchy to me. 100 or so feels just about right, and 110ish is positively divine.

    I'm often told by low-trail/steep HTA proponents that 'if I lived and rode at X' I'd want things different, and almost invariably when I go to visit and ride those places that turns out to not be the case. Often emphatically so. More often than not I've found that these folks are just parroting others, and have never experimented for themselves.

    To each their own, though.

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    Quote Originally Posted by mikesee View Post
    ...I always want a higher trail number than the industry is willing to offer. Anything less than 90mm and the bike feels sketchy to me. 100 or so feels just about right, and 110ish is positively divine...
    Oh, I'm not making myself clear. We're in accord over trail. I like heaps of trail too, just have a different way of getting it.

    This is done on a bike with a steep HA by having the appropriate fork offset.
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    I too believe that float and low rolling resistance can be had when increasing rim size.
    This effect has been observed by many when going from 26" to 29" with an other identical rim and tire. A 2.5" increase in rim size gave a significant advantage, especially over loose sand an snow, but also over rocks. Asphalt, the most likely condition for a taller rim to do well, offered the least if any improvement.

    That's why I posted earlier that the ultimate fat bike will have taller rims, and I proposed the same rim standard I proposed years ago for XC. 698mm bead size, where 29" has 622mm, and 26" and fatbikes have 559mm.
    Existence of 36" bikes (90cm tall wheel) without toe overlap, more than decent singletrack handling and outrageous roll-over ability (up-stairs) suggest that a 698mm rim with 4" fatty (just around 90cm as well) would be well rideable. the contact would be stretched out, the hotspot of surface pressure reduced. On top of this, it's known that a large rim diameter for a given tire cross-section will allow for lower tire pressures. Yes, at the cost of increased risk of hitting rims. Which immediately seems to be overcome with a slightly more "blunt" rim profile. 29"ers hit rims relatively often, but the snake bikes this produces is surprisingly low. More, softer hits?

    Depending on someone's prime riding style, the super-large fatty wheels will be a blessing or downring limiting. Every wheelsize is a compromize, but for every given terrain there is a sweetspot somewhere. IMO, for skinny tire XC, the ideal wheel size is the largest that doesn't compromize rider fit. Even tiny tiny women win WC's on 29" wheels. They are not disadvantaged, even on the challenging, steep and winding tracks of world cups.

    Only one effect I worry about with super tall fatty wheels is the knife-in-butter effect. Low-speed resistance when trying to steer the front wheel. A longer contact patch, after all, is like a taller knife being stuck into butter and then twisted, it's harder to do. I now realize as I white this, that the larger rim will have the tire sink in less deeply also, meaning less snow or sand to be shoved to enable a turn.

    Off-topic:
    Really out there: I am think of a chainless (and cardan-less) drive system to elinate all known issues with those in terms of space and performance. It would be based on magnetic interaction. Less likely to be useful for fat bikes I realize, due to the tall tires them selves. A crankset lined with magnet, and a rim or tire lines with magnets. these interact losslessly, acting as 2 virtual cogs. It would add weight, but also drop weight. Hubs would be front hubs only. No chain or cassette. But magnet on rim or tire, and a rather unique gearing above the BB. I have yet to research how much torque would make the practicle setup slip. It's not near infinite like a chain. But of course there are ways to increase torque from the bike's side while keeping the wheel somewhat light: multiple magnet cogs sharing the torque. Tell me it'll never happen. Maybe it's even been done before I brainfarted it first.

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    Quote Originally Posted by Guitar Ted View Post
    MG: I hear ya. I have felt some strange sensation in the front end of my Muk too. Even had the hub shift in the drops once. This is also on dry trail.

    Of course, we are putting a lot bigger footprint on the ground resulting in a lot more traction than our 29"ers have. Something has to give if the tire sticks better, ya know? It's like a football player on Astro-turf. The foot sticks like glue but the knee will give out when the guy gets tackled.

    You are familiar with the old, larger axle caps once tried on 26"ers. Specialized does this with their OS-28 end caps. I feel it helps a lot, and feels about the same as a 15Qr, to my mind. It could be a way to go to keep QR's and get rid of the funky feel.

    In the end, I think a thru-axle would help, but I am just suggesting that QR's may not have to go if they are used with the over-sized axle end cap concept. That said, Maxles are so easy to use, why not, right?

    As far as the rest goes, I see a bit slacker head tube angles being far better in loose stuff, and can be done to handle just great for trails. This past weekend's ride on snow really dialed me up to why slacker is better for the loose stuff.
    I like the idea of running a MAXLE-type of setup... Might be the ideal scenario for a fatbike rigid fork, with a solid-clamping skewer.

    And I like your ideas about slacker HT angles too, especially as we venture into 'suspension for fatbikes' territory. It totally makes sense to me for a number of reasons.

    Good stuff...

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    Quote Originally Posted by mikesee View Post
    I understand the effects of offset and trail very well, and I too have an adjustable offset fork to play with.

    I've experimented bunches, and my conclusion is a virtual mirror image of yours: More. As in, I always want a higher trail number than the industry is willing to offer. Anything less than 90mm and the bike feels sketchy to me. 100 or so feels just about right, and 110ish is positively divine.

    I'm often told by low-trail/steep HTA proponents that 'if I lived and rode at X' I'd want things different, and almost invariably when I go to visit and ride those places that turns out to not be the case. Often emphatically so. More often than not I've found that these folks are just parroting others, and have never experimented for themselves.

    To each their own, though.

    MC
    Mike, do you mean for snow bikes, or bikes in general?

    I have experimented with HTA/offset/trail/front center and know what I like for my riding style, at least for dirt, mud...
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    VeloBike:

    Put me down as one who has misunderstood you, I too assumed that you wanted a lower trail number.

    Are you then trying to get the control you desire by moving the axle back towards yourself, putting
    more weight on the front wheel, while not changing the trail number too much? In order to do that you must decrease the fork rake some, correct? This in turn, make toe overlap more likely, right? Something some try not to have when sawing on the bars, picking your way slowly about.

    Question:

    If the above is correct, why not figure how much ETT length you need for a given HTA and fork figures, just short of toe overlap, then add the reduction to the stem length to obtain your fit? Seems like I read
    somewhere that the two are not quite the same when applied. Did not understand though.

    With the former example, the fork would transmit a more direct, rougher feel than the latter, if that matters.

    Any corrections to me would be welcome.

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    One reason I suggested this is because my present 1989 26er (no FS) has a short TT and a long stem. I have done some rough measurements and with a fork to accept a 29" tall tire, it looks like a close fit.

    The BB and stays would have to be reworked though.

    Also, would I be correct to assume you have tried different bar widths to gain proper control?

    While that short TT and long stem work fine, I find myself longing for a longer TT and shorter stem, which is the direction frames in my size have taken sense '89. (about 1.5"+)

    Just a thought for your consideration in your pursuit.

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    If you take 2 bikes with the same wheelbase and riding position, then the one with the steep HA will need a longer top tube, hence a shorter stem to have the bars in the same place relative to the rider and front wheel.

    Most of what I have come to believe is needed with HAs and trail is as a result of experiments and modifications I made to motorbikes in the 70s to try to get them to handle at high speed on rough dirt roads. I lived on the edge of the desert in Oz and hundreds of miles to the next large town). Back then the standard Japanese motorbike had really dodgy handling, and we needed fast bikes simply to get anywhere. Ironically none of my mates believed my findings although they were quite happy to admit that my bikes handled better than theirs - they thought it was down to the suspension units which admittedly were nonstandard.

    This gave me the base for when I started to fiddle around with bicycle geometry.

    However, in the 80s, Tony Foale did a series of very interesting experiments on the same thing, and basically confirmed for me I was on the right track. He also points out the disadvantages of the telescopic fork - "The only drawback noticed – juddering under braking – is a consequence of the poor structural integrity of the telescopic fork as a type."

    If you click the link, you'll end up on his site, and there's lots of great resources there.

    BTW a very simple trick to increase trail if you have a telescopic fork is to pull off the lowers and replace them with the fork crown reversed. The fork looks the same to the casual eye, but because the crown is reversed, you have reduced the offset by twice its offset, and thus moved the vertical line dropped from the axle to the ground further back from the line drawn through the steering head to the ground - ie increased the trail. Obviously whether this does any good depends on the geometry of your bike and your forks construction (and at your own risk etc etc), but it is an easy thing to try. (I suspect this may not be so easy to do on the current batch of forks)
    Last edited by Velobike; 01-18-2012 at 07:22 AM.
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    How about using a 20mm thru axle. If I remember correctly isn't the spacing on them already 110mm rather than 100? It would stiffen things up enormously and there are already maxle offerings to make pulling your wheel not much harder than a standard QR. Redesign the fork slightly for the 10mm wider width replace the drop outs with pipes for the thru axle (threaded on one side for the maxle) and we're ready to ride.

  45. #45
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    Quote Originally Posted by woodi2259 View Post
    How about using a 20mm thru axle. If I remember correctly isn't the spacing on them already 110mm rather than 100?...
    Using an existing standard like that makes sense. I've been looking at 110mm hubs because I'm planning a new fork. I'd prefer a simple clamp on the fork - the time difference in removal would be minimal.
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    Looks like salsa already makes a thru axle rigid 29er fork. All they need to do is reshape the legs a bit to accommodate wider tires and I think it just might work well. Salsa Cycles | Components


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    Thanks for the referance to Tony Foale VeloBike, have read some of his work before, good for a re-read.

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    Quote Originally Posted by Sand Rat View Post
    Thanks for the referance to Tony Foale VeloBike, have read some of his work before, good for a re-read.
    Yeah, he did far more elegantly than I did.

    I like the bit where he gives the bars a knock at high speed to see if he could instigate a wobble. I've been spat off one of those R75/5s at speed and there's no way I'd be daft enough to try that on one of them in unmodified form.

    Still, it's a pretty good indication of the benefits.
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    VB

    Rode a R75/7 for many years, once hit a 6" deep X 18" sharp pot hole at about 55mph...never fazed
    the bike, my AMF built Sportsters...would hate to think.

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    How about accommodation for a kickstand?

  51. #51
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    Quote Originally Posted by Sand Rat View Post
    VB
    Rode a R75/7 for many years, once hit a 6" deep X 18" sharp pot hole at about 55mph...never fazed the bike, my AMF built Sportsters...would hate to think.
    Had a 75/7 when they were new - much better than the /5 series. Currently rebuilding a R100/7.
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    Lets see if I understand the what and why of your idea.

    Using your Pugs as an example.

    Remove the axle offset from the steering axis; 43mm.

    Add 43mm to your top tube length and subtract 43mm from your stem length.

    A HTA of 77* - 365mm wheel radius - @ Zero Offset = +/- 84mm trail.

    Why does this improve low speed stability?

    Does not an axle offset from the steering axis act as a rudder; in this case, in front
    of the 'boat', not at the rear? Get rid of it and you yourself become the rudder, in direct
    control.

  53. #53
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    Quote Originally Posted by Sand Rat View Post
    Lets see if I understand the what and why of your idea.

    Using your Pugs as an example.

    Remove the axle offset from the steering axis; 43mm.

    Add 43mm to your top tube length and subtract 43mm from your stem length.

    A HTA of 77* - 365mm wheel radius - @ Zero Offset = +/- 84mm trail.

    Why does this improve low speed stability?

    Does not an axle offset from the steering axis act as a rudder; in this case, in front
    of the 'boat', not at the rear? Get rid of it and you yourself become the rudder, in direct
    control.
    More trail = more "rudder" effect.

    Decreasing fork offset increases trail.
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  54. #54
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    Quote Originally Posted by Sand Rat View Post
    Lets see if I understand the what and why of your idea....
    Perhaps if you consider this way:

    Take the point where the imaginary line of HA hits the ground and regard that as the hinge of the rudder. Measure from here to the point where the tyre touches the ground to get the length of the rudder (ie your trail).
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    Quote Originally Posted by Velobike View Post
    4: Rear dropout width: Currently the offset 135 is the most useful setup, but this creates potential problems with wheel builds. Unfortunately once we go for a symmetrical wheel build we lose the ability to use hub gears. I suspect that changes here have to come from the hubgear manufacturers rather than the frame builders. The only 170mm hubgear is the S-A and with only 3 speeds it is too limited a range for most people.
    How hard would it be for IGH manufacturers to put out a 170mm hub? It’s not like they’d have to shrink the internals. They likely wouldn’t have to reengineer anything significant, just put the innards into a bigger hub. Maybe what we need is for an organization like MEC to express an interest in buying a couple of hundred 170mm Alfine 11s, for example? That ought to be enough to get someone to fire up the AutoCAD. MEC aren’t groundbreakers, however, and they’re going to have to have to be convinced that fatbikes have become established before they make plans to carry them.

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    Quote Originally Posted by shiggy View Post
    Mike, do you mean for snow bikes, or bikes in general?

    I have experimented with HTA/offset/trail/front center and know what I like for my riding style, at least for dirt, mud...
    In general.

    It's interesting (if only to me) that I've ended up at similar trail numbers (within 5mm) on my XC, DH, AM, and fat bikes, though that was never the goal.

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    Cart before the horse? And the horse is (dying) dead?

    Quote Originally Posted by BowHopper View Post
    How hard would it be for IGH manufacturers to put out a 170mm hub? It’s not like they’d have to shrink the internals. They likely wouldn’t have to reengineer anything significant, just put the innards into a bigger hub. Maybe what we need is for an organization like MEC to express an interest in buying a couple of hundred 170mm Alfine 11s, for example? That ought to be enough to get someone to fire up the AutoCAD. MEC aren’t groundbreakers, however, and they’re going to have to have to be convinced that fatbikes have become established before they make plans to carry them.
    I understand that for a very small (yet very vocal) minority, IGH's are the bees knees. Super.

    But from the perspective of someone that builds heaps and hordes of wheels (I've built about 13,000 in the last ~10 years) I just don't see any demand for them.

    Of the wheels I've built:
    ~89% use a multi-gear (8/9/10 spd) cassette.
    ~10.9% are SS-specific.
    ~.1% are IGH. That's point-one-percent. Probably a lot less.

    Worth mentioning: I keep Rohloffs, A8's, and A11's in stock, along with the necessary accoutrements like rotors, shifters, cogs, spacers, etc... So when someone comes looking for one, and they really know what they want, I'm ready to lace it up for them.

    But that almost never happens. I think I built 3 Rohloff's and 3 Alfine's last year, amidst 1100+ derailleur or SS-based wheelsets.

    For those that like IGH's and run them, great. My seat of the pants guess is that there are more folks out there that have run them and NOT liked them, then switched back to derailleur-based systems, than there are people still running IGH's.

    The drawbacks (cost of high end models, weight, PITA factor for changing flats/wheels/tires, lack of durability on lower end models) don't come remotely close enough to make IGH's compelling to the masses. Not yet, and probably not for a long time to come. If ever.

    Until the demand is there, there's just not much of a compelling reason for any entity to dump the time and money into making the hubs. And without a functional, durable, and affordable hub to showcase, market, and sell, the demand isn't increasing--at best it's flat.

    edit: Just realized that it's also pretty accurate to substitute 'dynamo hub' anywhere that I've typed IGH above.

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    I keep meaning to see if I can fit the guts of a 5 speed S-A hub into the 3 speed 170mm. Just got too many projects banked up.
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    BowHopper - I am one of the vocal IGH proponents that mikesee refers to. But I recognize the minority, and drawing some stuff in CAD is way easier than machining and testing. Those difficult things cost a lot up front, and no one's going to make the stuff if they don't think they're going to recoup their loss and then some.

    Which, well, they probably wouldn't.

    I've repeatedly reevaluated my opinion on gear hubs and switching back to derailleurs, and even when my clumsy ass succeeds in not bending them or their hangers, they still just piss me off.

    I have one thought specifically on the pain of changing wheels. A valid criticism, for horizontal dropouts, changing an IGH wheel sucks. Sliding dropouts do help, but, none of the cable quick release schemes I've played with can compete with the simplicity of a V-brake quick release (which you can just squeeze, pull, and go).

    I've thought one answer could be electronic shifters. Little electric motors can be torquey and cheap. The quick release could be something super easy like some Anderson connectors. But, this is still added cost and complexity for the sake of simple interaction.

    For my own part, I'd love to rip apart an Alfine and shove a longer axle and make a replacement wide body. But, I've become intimately aware of my own limited fabrication experience, so it's a ways off to say the least. If I ever figure it out, I will gladly take your money, but don't hold your breath.
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    +1 for an IGH at 170mm. Vocal minority I know.

    But what I'd really like is non-inverted, 20mm thru axle, single crown suspension fork from a big name like Fox or Rock Shox. Just take an existing platform like the 36 TALAS and make a wider crown. Same stanchions, same internals, same adjustment features (though maybe make the dials a little bigger for gloved hands.

    That is all.

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    Quote Originally Posted by SRALPH View Post
    +1 for an IGH at 170mm. Vocal minority I know.

    But what I'd really like is non-inverted, 20mm thru axle, single crown suspension fork from a big name like Fox or Rock Shox. Just take an existing platform like the 36 TALAS and make a wider crown. Same stanchions, same internals, same adjustment features (though maybe make the dials a little bigger for gloved hands.

    That is all.
    Show them the ROI and it might happen. Maybe.

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    Quote Originally Posted by mikesee View Post
    Show them the ROI and it might happen. Maybe.
    And that's the real crux of the matter.

    In the meantime the innovation has to be done by ourselves.

    I can't see much chance of a big manufacturer putting the investment in when the potential sales are only a few hundred 170mm hub gears. Maybe when (or if) the demand for hub gears grows we might see this happen.
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    Quote Originally Posted by Velobike View Post
    I can't see much chance of a big manufacturer putting the investment in when the potential sales are only a few hundred 170mm hub gears. Maybe when (or if) the demand for hub gears grows we might see this happen.
    A few hundred?

    I think that's beyond optimistic. Unless/until you have a solid distribution network, mechanics in shops that know how to work on them, access to replacement parts, and a few *years* to recoup the investment, I think a few dozen is probably more accurate.

    All of which is unlikely.

    I like the idea of IGH's (from many perspectives) on just about any 2-wheeled human-powered vehicle, but the theory has not yet matched the potential.

    Cheers,

    MC

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    Quote Originally Posted by SRALPH View Post
    But what I'd really like is non-inverted, 20mm thru axle, single crown suspension fork from a big name like Fox or Rock Shox. Just take an existing platform like the 36 TALAS and make a wider crown. Same stanchions, same internals, same adjustment features (though maybe make the dials a little bigger for gloved hands.
    A wide fork would have been relatively easy when they used bolt on arches and pinch bolt crowns. Now it requires all new toolings for the stanchions and crowns.

    Maybe we should stock up on 2000 Z1 Bomber forks an make new crowns and arches for them.
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    Quote Originally Posted by SRALPH View Post
    +1 for an IGH at 170mm. Vocal minority I know.

    But what I'd really like is non-inverted, 20mm thru axle, single crown suspension fork from a big name like Fox or Rock Shox. Just take an existing platform like the 36 TALAS and make a wider crown. Same stanchions, same internals, same adjustment features (though maybe make the dials a little bigger for gloved hands.

    That is all.
    Fabbing a wider crown to hold the stanchion legs wider is not terribly difficult, the challange is that since all non-inverted forks these days have the lower legs cast together with an integral connector arch, you would need a new special casting for the wider lower legs. I dont think that cutting/welding an existing arch would work well. Starting with an anchient pre Y2K fork that has a removeable bolt-on arch allows you to widen the stance with a custom arch.

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    Quote Originally Posted by mikesee View Post

    Until the demand is there, there's just not much of a compelling reason for any entity to dump the time and money into making the hubs. And without a functional, durable, and affordable hub to showcase, market, and sell, the demand isn't increasing--at best it's flat.

    edit: Just realized that it's also pretty accurate to substitute 'dynamo hub' anywhere that I've typed IGH above.
    (Added emphasis mine)

    Mike, I think the thing that holds it all back is the durability of anything IGH other than the possible exception of a Rohloff. At least from the perspective of mountain biking/fat bikes. I won't buy into it until that gets sorted at the very least. The other hurdles are significant, but could be overlooked if the hubs fit and lasted when things got tough.

    I'm thinking in terms of front dynamo hubs, the technology is getting pretty close, it just isn't going to come in a "fatbike friendly" format anytime soon. Too bad. I like what I've seen so far of the newer set ups.
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    Quote Originally Posted by Drew Diller View Post
    BowHopper - I am one of the vocal IGH proponents that mikesee refers to. But I recognize the minority, and drawing some stuff in CAD is way easier than machining and testing. Those difficult things cost a lot up front, and no one's going to make the stuff if they don't think they're going to recoup their loss and then some.

    Which, well, they probably wouldn't.

    I've repeatedly reevaluated my opinion on gear hubs and switching back to derailleurs, and even when my clumsy ass succeeds in not bending them or their hangers, they still just piss me off.

    I have one thought specifically on the pain of changing wheels. A valid criticism, for horizontal dropouts, changing an IGH wheel sucks. Sliding dropouts do help, but, none of the cable quick release schemes I've played with can compete with the simplicity of a V-brake quick release (which you can just squeeze, pull, and go).

    I've thought one answer could be electronic shifters. Little electric motors can be torquey and cheap. The quick release could be something super easy like some Anderson connectors. But, this is still added cost and complexity for the sake of simple interaction.

    For my own part, I'd love to rip apart an Alfine and shove a longer axle and make a replacement wide body. But, I've become intimately aware of my own limited fabrication experience, so it's a ways off to say the least. If I ever figure it out, I will gladly take your money, but don't hold your breath.
    I should say first off that I’ve never owned a bike with an IGH, but I do like the idea. I think the front derailleur on my winter commuter has officially succumbed to the salt and grime, and the rear isn’t in great shape either, and I’ve been thinking about how great it would be to have an IGH protected from the elements.

    The MEC I mentioned in my above post is a chain of stores in Canada somewhat like REI in the US, except they have their own line of bikes. They’ve been using Nexus and Alfine hubs on their Urban line of bikes for some years now, so it appears there's more of a demand for IGHs in Canada. Maybe the weather is a factor? You Alaskans (and Minnesotans ) seem to be fairly pro IGHs as well.
    MEC Hybrid & Urban Bikes - Mountain Equipment Co-op (MEC). Free Shipping Available

    I wasn’t really suggesting that all there would be to making a 170mm hub would be doing the drawings, but it shouldn’t be all that hard. Making the hub bigger means that the internals could for the most part say the same. They just have to do is put them in a bigger hub. It sounds like Shimano is having a few issues with the Alfine 11, however, so they probably want to get those sorted out first. The only other major variable I can think of is that since these would be used on winter bikes they’d probably want to make sure they worked down to something like -50C, and they may not have tested the current ones at those temperatures.
    Last edited by BowHopper; 01-19-2012 at 10:03 PM.

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    Quote Originally Posted by mikesee View Post
    A few hundred?

    I think that's beyond optimistic. Unless/until you have a solid distribution network, mechanics in shops that know how to work on them, access to replacement parts, and a few *years* to recoup the investment, I think a few dozen is probably more accurate.

    All of which is unlikely.

    I like the idea of IGH's (from many perspectives) on just about any 2-wheeled human-powered vehicle, but the theory has not yet matched the potential.

    Cheers,

    MC
    Just to flesh out what I said in my post to Diller. MEC – which stands for Mountain Equipment Coop, and yes they are a real member owned coop - carries 10 different adult bikes and 3 of them use IGHs. They use the Nexus 8, Alfine 8, and Alfine 11. They also have 15 big stores across Canada, and they do a very strong mail order business as well, because they have a great reputation and are very popular. We Canadians loves our MEC. They also have their own bike mechanics in each store.

    They aren’t ground breakers, however. They don’t have a fatbike yet, for example, although I believe they’re testing them out. They keep on top of what’s going on, but they tend to come in with the second wave, once the technology has been proven. Assuming they decide fatbikes will become a standard winter bike in Canada, I could easily see them asking Shimano to produce 170mm Alfine 11s for them. I’d only be guessing at the number of bikes they could sell, but if you think about the number of fatbikes sold in Alaska in recent years, and then consider that Calgary alone has 1.5x the population of the entire state of Alaska, and Canada as a whole has 50x the population of Alaska, you can see that Canada is a significant potential market for fatbikes.

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    Great info.

    I'm familiar with MEC but I was not familiar with how many IGH's they move. Could be them as easily as anyone else that makes it happen.

    Cheers,

    MC

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    Hub gears are pretty common in Europe, and as more people get into winter riding on their mtbs, they are getting common on mtbs as well.

    In the recent StrathPuffer 24 hour I estimate about 10% of the riders were on them which is a big leap from just a few years ago.

    Quite a few new bikes are provided with them these days.

    But Mike is right, there has to be a significant and obvious large potential market before we are likely to see a fatbike 170mm hub gear from the likes of Shimano.

    Edit: figured I should do something about this, so I've asked S-A if they can stick more gears into their 170mm hub, or if they think it's possible for me to do a home modification of mine.

    Here's their FaceBook page - maybe if they start seeing direct requests, they'll consider it.
    Last edited by Velobike; 01-20-2012 at 04:06 AM.
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    Getting back to your idea again. Read where the riders of BMX style bikes sometimes have a
    fork with zero offset, which they use to assist them in standing on the front wheel, while spinning
    the rear of the bike about.

    Would this mean that having a fork with zero offset make the bike more endo prone, and if a trailing
    axle more so yet? If so, would having a wheel with a larger diameter in front over the rear, so as to keep a low CG help? (36 -29?)

    I noticed that Foale did not try a panic stop test down a steep grade. His aim seemed to test the
    limits of an idea rather than create a new design.

    Still, for your intended useage, it is an interesting idea, that I can see merit in, for your speed
    would be quite on the slow side

    This tread has enabled me to picture in my mind the forces at play with bicycles; the rudder
    thing, better than ever before. So thanks to you.

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    Quote Originally Posted by Sand Rat View Post
    ...I noticed that Foale did not try a panic stop test down a steep grade. His aim seemed to test the limits of an idea rather than create a new design....
    It wouldn't make much difference on a bicycle with a rigid fork. It's all about the centre of gravity of the rider, and we haven't changed that.
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    Shaft driven fat bike? No worrying about chain rub at least..

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    Quote Originally Posted by Sand Rat View Post
    ...Read where the riders of BMX style bikes sometimes have a fork with zero offset, which they use to assist them in standing on the front wheel, while spinning the rear of the bike about.

    Would this mean that having a fork with zero offset make the bike more endo prone, and if a trailing axle more so yet? ...
    Not with the way I setup/design my bikes.
    I know the total reach I want on a bike, and where I want my hands in relation to the front axle. I set that position first. Then the trail and HTA are put in. The ETT and stem lengths are then whatever they come out to be. It is all about the weight distribution for me.
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    Quote Originally Posted by mikesee View Post
    Show them the ROI and it might happen. Maybe.
    Fox, Rockshox and the others won't touch a product unless it will turn 10,000 units in the first year.

    Life-to-date - there are 4000-6000 fat bikes on the worldwide market, the vast majority of which are not suspension correct, and about half of which are probably 170mm hubs.

    Based on Mike's sales history, that would make worldwide demand for 3 internally geared 170mm hubs.

    The companies know these facts, and this is why you don't have nice things.

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    Quote Originally Posted by Sand Rat View Post

    Would this mean that having a fork with zero offset make the bike more endo prone, and if a trailing
    axle more so yet? .
    Lots of folks forget about Joe Breeze's experimental bike in the 80's with a no-offset fork/zero reach stem.

    He said after he got used to it, he could keep up with all his riding buddies just fine.

    All it means is that humans are very adaptable creatures. Whether you want to/like to adapt is the biggest thing.
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    Quote Originally Posted by Velobike View Post
    Hub gears are pretty common in Europe, and as more people get into winter riding on their mtbs, they are getting common on mtbs as well.

    In the recent StrathPuffer 24 hour I estimate about 10% of the riders were on them which is a big leap from just a few years ago.

    Quite a few new bikes are provided with them these days.

    But Mike is right, there has to be a significant and obvious large potential market before we are likely to see a fatbike 170mm hub gear from the likes of Shimano.

    Edit: figured I should do something about this, so I've asked S-A if they can stick more gears into their 170mm hub, or if they think it's possible for me to do a home modification of mine.

    Here's their FaceBook page - maybe if they start seeing direct requests, they'll consider it.
    FB comment/request = DONE
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    Quote Originally Posted by bikeindustrydude View Post
    ...that would make worldwide demand for 3 internally geared 170mm hubs...
    You're forgetting that cruisers use 170mm hubs too.

    It's a new market, it will evolve, just as it took time to get suitable parts for mtbs. Once there were only a few thousand mtbs.

    I have a 170mm frame and putting a derailleur on it would be foolish. It would be ripped off or bent within half an hour of riding it through thick heather. If I want gears there is no alternative to an enclosed gear system. Evolution will happen.
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    Quote Originally Posted by Guitar Ted View Post
    Lots of folks forget about Joe Breeze's experimental bike in the 80's with a no-offset fork/zero reach stem...
    Can't see any problem with that. It would have had lots more trail, so sounds like the real change was riding position only.

    Look at the traditional gentleman's roadster. The grips are well behind the steering head and they are a very stable bike.

    Edit: I've searched for a pic of that bike with no luck. Anyone know a link?
    Last edited by Velobike; 01-21-2012 at 03:10 AM.
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    Quote Originally Posted by bikeindustrydude View Post
    Fox, Rockshox and the others won't touch a product unless it will turn 10,000 units in the first year.

    Life-to-date - there are 4000-6000 fat bikes on the worldwide market, the vast majority of which are not suspension correct, and about half of which are probably 170mm hubs.

    Based on Mike's sales history, that would make worldwide demand for 3 internally geared 170mm hubs.

    The companies know these facts, and this is why you don't have nice things.
    I’m not following everything you’re saying here, but note that in this case we’re not talking about developing a new product. That’s a very different proposition. We’re not talking about spending the resources that would be required to develop a new internal gear hub, for example. We’re talking about taking an existing product, the Alfine 11, and modifying it in a fairly simple way to appeal to a new market. You could well argue that doing this would increase the ROI on the Alfine 11, because with this minor modification you’re opening up a new market area and increasing sales. The key is in how difficult it would be to stick the existing Alfine 11 internals into a 170mm hub, and I can’t see that being all that difficult.

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    Quote Originally Posted by Guitar Ted View Post
    Lots of folks forget about Joe Breeze's experimental bike in the 80's with a no-offset fork/zero reach stem.

    He said after he got used to it, he could keep up with all his riding buddies just fine.

    All it means is that humans are very adaptable creatures. Whether you want to/like to adapt is the biggest thing.

    It's important to note that the frame had a 78 degree head angle.

    Velo, here is an old thread with some info about the bike: Joe Breeze / Otis Guy head angle tests

    I think there is another thread somewhere with better photos and more detailed comments (some by Joe himself, as I recall) but I'm not sure which forum it was in.

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    Thanks for that link.

    That illustrates what I'm talking about. Still plenty trail on that bike. The limitation may be the length of the toptube necessary - it looks like it could have been a bit flexy. Not a problem with the options for frame building these days.

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    Andy

    A me too on the thanks dept.

    Did several searches for info on the bike myself, but only came up with references to it.

    Does not look too bad, the shape seems to grow on ya the more you study.

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    Quote Originally Posted by Velobike View Post
    Thanks for that link.

    That illustrates what I'm talking about. Still plenty trail on that bike. The limitation may be the length of the toptube necessary - it looks like it could have been a bit flexy. Not a problem with the options for frame building these days.

    Hardly a change of one or two things (fork offset and stem length).
    From the pic it appears the front center is similar to the "normal" bikes of the time.
    Steeper HTA and no offset would keep the the trail close to or the same.
    The bar remains in about the same place relative to the front axle.
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    The thing the screams out with this design is road shock.

    What if you were to take a design not unlike the Jeff Jones truss fork and turn it
    upside down?

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    Internal gear hubs and dyno hubs are here and work just fine on fat bikes. I don't plan on
    stumble f'ing across a glacier toe with a raft tied to my rack, my riding is all AM/XC. Hero
    worship is fine and well, emulating your hero's bike might not be a good practice based on
    what the bike/rider will really experience.

    The biggest issue with internal gear hubs and dyno hubs is most LBS are clueless and can't
    work on something new. Don't go for an IGH or dynohub unless you have a little DIY ability.

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    Quote Originally Posted by pursuiter View Post
    Don't go for an IGH or dynohub unless you have a little DIY ability.
    The ability to read instructions is all you need for the hub gear. Set to the marks and never ever twiddle to get the gears by "feel".

    The other evolutionary change needed is a set of lightweight mudguards (fenders) that actually do the job.
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    Quote Originally Posted by Velobike View Post
    The ability to read instructions is all you need for the hub gear. Set to the marks and never ever twiddle to get the gears by "feel".
    I admire optimism in all it's forms but this is just exceptional.

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    Quote Originally Posted by mikesee View Post
    I admire optimism in all it's forms but this is just exceptional.
    Why? I've been using & fixing hub gears for decades, and almost every "broken" one I've come across was a simple case of maladjustment by derailleur minded cable twiddlers or "stretch" in a new cable..
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    Quote Originally Posted by Velobike View Post
    Why? I've been using & fixing hub gears for decades, and almost every "broken" one I've come across was a simple case of maladjustment by derailleur minded cable twiddlers or "stretch" in a new cable..
    That's interesting.

    Every 'broken' IGH I've seen or laid hands on has had broken bits rattling around inside that had nothing to do with twiddling.

    The resultant wait for parts or service DID in fact result in lots of twiddling--of thumbs.

    Usually the twiddling stopped when the rider decided that yes, indeed, installing a derailleur-based system would solve the problem that they'd intended to fix in the first place: That of unnecessary downtime due to broken bits.

    Cheers,

    MC.

  91. #91
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    Quote Originally Posted by mikesee View Post
    ...Every 'broken' IGH I've seen or laid hands on has had broken bits rattling around inside that had nothing to do with twiddling...
    Best way to actually break* a hub gear is to ride it after twiddling the adjustment instead of setting it to the marks, so I'm sure there was some twiddling done. Of course, it could be the dreaded by bike shops JRA

    What hubs? Sturmey-Archer sell parts and they are readily available. Just about any bike shop over here with an older generation mechanic would be able to strip and rebuild a S-A hub in short order. Any part you want is a next day delivery and they are reasonably priced.

    Shimano looks like it's dropped its bundle on its 11 speed, and they don't seem to sell any individual parts, just sub-assemblies. Their 8 speed seems reliable enough - I don't know of any breakages in normal use.


    *Oh, forgot another way to break some S-A hubs, let a knuckle dragger adjust the cones. There's got to be a precise amount of axle showing on the rhs.
    As little bike as possible, as silent as possible.
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  92. #92
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    The last S-A hub I've seen was one I owned back in '98. Simple it was, and I liked that. It was also heavy, nutted, and otherwise unimpressive.

    But S-A seems to have all but vanished from North America. They are available to buy, but like I said--the last time I saw one was almost 15 years ago.

    "Older generation" mechanics seem to have gone wherever the S-A hubs are--you just don't see many of either.

    Which means that IGH's are readily available for John Q. Public over here from Shimano, SRAM, Rohloff, and Nuvinci. Due to the combination of price, weight, and some other blend of factors, the Shimano Alfine's have become the go-to hubs.

    And they have been GREAT--for light riders, pavement riders, or people that just don't ride much.

    Stick one under a hi-torque rider for a solid month and cross your fingers that the hub makes it out the other side. Some do, most do not.

    You can dance around the lack of durability by blaming it on misadjustments, twiddling, or some other farcical malady. Seems clear you're unwilling to accept that they are a two-bit "solution" to a problem that exists mainly in your mind.

    I haven't seen any true Rohloff failures, but I've laced cassette-hubbed wheels for many, many, many folks that have tired of the inherent "uniqueness" of that system.

    Cheers,

    MC

  93. #93
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    I tried repairing a S-A hub. After the unsuccessful repair they sent another hub altogether. Same problem. Ended up building a entirely new wheelset IGH free.
    As for Shimano Alfine hubs, we're on our 5th warranty. In none of these cases did an IGH solve any problems. The customers just wanted to try out the "new" technology.
    I have also seen the puddles of kerosene on the floor of the garages due to leaking seals of folks running Rohloffs in winter, since the factory lube is too thick for cold climates (which, by the way voids the warranty).
    In some areas IGH's might make sense. In most others they don't. Heavy, excess drag, limited gear range, and in some cases, ridiculously expensive. I have used derailleurs in heavy mud, deep snow, and terrible ice for 34 years. They work, and on the few occasions they didn't, I was able to make them work again trailside.
    Speedway Cycles owner http://fatbackbikes.com

  94. #94
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    Thank you for that, Thirstywork.
    Still cleaning my Fatback.
    It's a life style.

  95. #95
    Sup
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    I have been following this thread and just am wondering
    am I stupid for being completely satisfied with my 907
    the only thing I do not like on my bike is the BFL on the front
    one more Nate 3.8 on the way for the front and the bike is spot on
    I think adults we over think things
    my 7 year old never once ever mentioned one thing he would change on his bike

    this post is brought to you by Guinness Draught
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  96. #96
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    Quote Originally Posted by SlowerJoe View Post
    I have been following this thread and just am wondering
    am I stupid for being completely satisfied with my 907...

    this post is brought to you by Guinness Draught..
    I don't think many of us are dissatisfied with our bikes, just trying to work out what direction they'll go in.

    I've found Guinness is a wonderful aid to clear thinking too, but somehow the clarity has disappeared when you look at things again the next day.

    It looks like hub gears aren't popular in USA*, so the need to allow for fitment of these will not be important to their market. For the rest of us that means that there's one bit of evolution we're probably not going to see until fatbikes become common currency in Europe.



    * I don't want to go too far OT here by arguing the merits - or otherwise - of hub gears, but from what has been said above by reputable people, hub gears are too fragile for USA riders, or don't work in extreme cold.
    As little bike as possible, as silent as possible.
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  97. #97
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    Quote Originally Posted by thirstywork View Post
    ... I have used derailleurs in heavy mud, deep snow, and terrible
    ice for 34 years. They work, and on the few occasions they didn't, I was able to make them
    work again trailside.
    Typical LBS, can't understand anything new, must keep status quo. Besides, if you can't make
    it work, nobody can. This is what passes for considered thought in the bike industry. That's
    why Trek and Spec dominate, it's not technology, it's marketing....

  98. #98
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    I agree that:

    - The support supply situation for IGH hubs is poor due to unpopularity.
    - The price is wrong.

    I can neither confirm nor deny that:

    - Heavy riders blow up hubs, though the claim makes sense. (I only weigh 170 and haven't broken anything.)
    - They're slower. I don't know about that. The NuVinci in the lower gear range, yes. Manufacturers are more than shy about posting numbers. Has anyone hooked one up to a testing rig, no, the few people who would care don't have the equipment. I'd say due to unpopularity, there aren't enough people available to find the crazy guy who is willing to test them independently.

    I ride gear hubs because:

    - I've broken more than my fair share of hangers. I don't care if you can fix it trail side, I'd rather have it not happen at all, and keep riding. That has to be the most valid argument for gear hubs assuming they had a universally tough service life (which they apparently do not).
    - I hate stopping for chain suck.
    - I don't like have to do the "I am in this gear in the front, and this gear in the back" mental tracking. It's asinine. Cars don't do this - you shift in one place. It is for this reason that I'm interested in trying a 1x10 soon and just crossing my fingers about the rear.
    - I don't like being stuck in an awkward gear and having to do the awkward gear change dance when getting going again. I like to shift just standing around.

    Of the bike swapping I've done with people, the only internal gear device that someone became immediately interested in was the Hammerschmidt. I don't understand why more hubs aren't built like that unit - open it up, its freewheel pawls are burly.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  99. #99
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    Quote Originally Posted by pursuiter View Post
    Typical LBS, can't understand anything new, must keep status quo. ....
    Come on Pursuiter, Can't understand anything new and must keep status quo? Thirsty and Pete have been helping to push the fatbike movement since brfore it was a movement.
    Latitude 61

  100. #100
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    Sorry if I went too OT. Summing up:
    -IGH's could be a great solution, not just for fat bikes. But they aren't "there" yet.
    -In order to get better, there needs to be both consumer demand and manufacturer interest in improving the genre. Neither are happening on any scale right now.

    Perhaps the push to go wider than BFL's on 100's will be the straw that breaks the camel's back and convinces both buyers and sellers to support IGH's.

    Cheers,

    MC

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