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  1. #1
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    Fatbike geometry for snow and slower-speed chunk

    Can someone help me understand what kind of geometry works best in snow? Not just powder, but generaly ugly slower-speed conditions:


    • Ugly snow: frozen footprints, ruts, etc
    • Non-snow chunk: rocks, roots, etc
    • Short but steep up and down hills


    I have read that slacker and longer bikes are more stable and thus better for snow. But I'm also reading others say that steeper head angles are better for handling in ruts and help avoid self-steer (here and here).

    I really have on idea what geometry I should be looking for. 907 seems to go for longer chainstays and not too steep a head angle (18.4 CS and 70 HA)

    I see the upcoming ice cream truck which has 69 degree HA and probably long chainstays. It's described as: "You have to use your whole body to move the bike, but it’s an incredibly stable ride”. Would this be good or bad for snow?

    Then there's bikes like the Yampa (69.8 HA, 18.2 CS) vs the Spesh Fatboy (70.5 HA, 17.9 CS) Is one more suited for slower-speed stuff? Or is this all in the camp of "doesn't matter just ride"?

    And before anyone tells me to "go test ride them". I'd love to take one of each for a day ride in various conditions, but that's not feasible. I have to rely on help from those who have more experience than I do!

  2. #2
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    For me out of all the fat bikes I have had I like 69.8 the best. As far as chain stay I do like the little bit longer for stability. I think rockers would be the perfect choice so a person could play around some and find the sweet spot.
    And I love beer!!

  3. #3
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    Quote Originally Posted by bdundee View Post
    For me out of all the fat bikes I have had I like 69.8 the best. As far as chain stay I do like the little bit longer for stability. I think rockers would be the perfect choice so a person could play around some and find the sweet spot.
    Thanks. Do you mind expanding on which bikes you have tried and what conditions you ride? 69.8 sounds like a Yampa.

  4. #4
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    I pretty much only use mine in the winter so take that into account.

    Pugsley 2 of them=steering is a little to quick for my liking and I like the slider set to about the middle position for snow but short does make it a little more playful.

    U.S. made 907= Very stable 18.5 cs stay and HA was 70 deg. it was a decent snow bike.

    2012 US made Fatback cs stay was good right around 18.2 but the HA was at 69 wich was ok but could have been a tad faster. The new Fatback I believe went to 69.8 deg. but I could be wrong.

    Yampa= Spot on steering at 69.8 and with CS at 18.2 seems great as well.

    Just one interweb idiots opinion so take it for what it's worth.
    And I love beer!!

  5. #5
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    Re: Fatbike geometry for snow and slower-speed chunk

    Quote Originally Posted by bdundee View Post
    Just one interweb idiots opinion so take it for what it's worth.
    One idiots opinion is better than none! Thanks for your input.

    The Yampa was beyond my budget but I was going to spring for it anyway. Until I realized it ships with 65mm Marge lites. To purchase a new clownshoe wheelset plus bud & lou will be another grand. That puts me at $4600 when I could walk out the door with a fatboy with 90mm rims and 4.6 tires for a total of $1850.

    I don't think I can resist what the specialized machine is offering. I might be on a fatboy soon.

  6. #6
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    Well, I've ridden my Farley quite a bit on dirt and I really like the way it climbs but not thrilled about chunk and really steep stuff. It is a chore to break traction though and my confidence is pretty high in most situations.

    By the time I got the Fatboy there was snow on the ground so it has never seen dirt but has plenty of snow time on it. So far I love it and have found it to be very easy to control on all but the absolute bumpiest rotten postholed disaster of a trail and even then I was able to pedal through it slowly like I was in 4 Low in my old Willys CJ5. What little high speed rolling I've done has been a blast and has me itching to get on dirt. The climbing has been limited by the snow but so far it has done everything within reason and a few things better than I expected.

  7. #7
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    Quote Originally Posted by bdundee View Post
    For me out of all the fat bikes I have had I like 69.8 the best. As far as chain stay I do like the little bit longer for stability. I think rockers would be the perfect choice so a person could play around some and find the sweet spot.
    I'm on a Mukluk and I had moved my rear tire/wheel all the way back when the snow was soft and I haven't moved it again YET! & I'm riding tight single track on packed snow. I will move the tire forward when the snow is gone. OP I would say as for CS the bikes with the shorter CS are more race and dirt single track summer bikes and the longer chain stay bikes you can do all that too but it's not going to have the rear tire poking thru the snow as easy (Float) as much as I don't like that word float, I got on my bike the first ride & went real fast into 3ft of snow and the only float was me over the bars) I was also looking into all this stuff and it came down to three bikes for me the 907, the Mukluk2 and the Specialized fatboy I got the mukluk because of being able to move the rear wheel back and forth and I use a 177mm x 12mm thru-axle alternator plate but I'll have to change out the rear hub also. If I had any of the other two bikes I would be just as happy them too.

  8. #8
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    Ugly snow: frozen footprints from people and our dogs. That's kind of funny but not really I have been snowshoeing a trail to keep it packed down and I can't keep up with the walkers (the walking dead)and their foot pot holes.

  9. #9
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    Quote Originally Posted by idinomac View Post
    I got the mukluk because of being able to move the rear wheel back and forth
    Interesting. How do you find the steering at low speeds?

    The geometry of your Mukluk with the hub all the way back might be close-ish upcoming Ice Cream Truck.

  10. #10
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    It's amazing how much nicer my necro pugs is with the rear tire all the way back. Easier to track on narrow trails, more stable going fast down chunky mess, better leverage climbing, more weight up front which sometimes helps with float. Much less rider steering workload at slow speeds.

    For the summer, I might move it forward like I had it last summer. Or maybe not--looking forward to experimenting with it.

  11. #11
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    What do you use in your Pugs to move the wheel back: Monkey Nuts, Tuggnuts or something else? I've been thinking about doing this to increase stability in snow.

  12. #12
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    Here is a link that may be of help...written in a way that makes geometry more easily understood, for me at least.

    Spectrum Cycles | Geometry

    Good luck

  13. #13
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    fwiw for mtb geo discussions in general, it doesn't make sense to just discuss HA or trail / fork offset without also discussing stem and bar setup. a slack HA / high fork offset setup can work great with a short stem and wide bar, but really feel terrible with a long stem.
    Originally posted by bucksaw87
    I still fail to see how mustaches, fixies, and PBR are ironic.

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