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Thread: Fat Bike FAQ's

  1. #1
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    Fat Bike FAQ's

    This thread is to address the most frequently asked questions fat bike riders get. I am no expert, but some here are and are welcome to add questions and answers.

    The first comment I get all the time is, what size are the tires.

    They are 26x3.7 inches wide and weigh about 1200 grams. they are made by a company called surly. http://www.surlybikes.com/
    You use a tube in them and run about 5-10psi depending on the terrain.

    There are some other tires available in the 26x3 inch size. they are Nokian and Arrow.
    They are more of a downhill tire than a snow tire. They are often used because they fit more frames and forks.
    These tires usually weigh about 1600 grams. Arrow still makes them and they are called the savage http://www.arrowracing.com/home.html
    The nokians will be hard to find, because they dont make them in the 3in size anymore.
    Last edited by rockcrusher; 03-10-2009 at 05:24 PM.

  2. #2
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    Tires, does Nokian still do them? The Arrows are 15lb for the pair (seriously), so bring your quads for those!

    Tire pressure?
    They run really low, like, 5 PSI low. More than 30 and they get scary

    "What's the bike for???"
    Sand, snow, anything else you feel like riding, and making you smile from the first pedal stroke

    "Are those motorcycle tires?"
    No.

    "Is everything special for them?"
    Frame, fork, bottom bracket, tires tubes, and the need for two rear, specific rimmed Pug wheels.

    All I can think of at the moment, sure others will percolate up through the fog...
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  3. #3
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    Soft condition riding

    I get this one a lot:

    "I want to ride on really loose sand and snow, how do they work?"

    Despite their ability to take you places no other bike can go, Fat Bikes do have their limitations. Even with the 3.7" tires and 65, 80, and now 100mm rims, you will probably find that they can bog down in really loose conditions like unconsolidated beach and dune sand, powder and loose granular snow, shale, and pea gravel.

    Often you will be able to ride downhill and maybe even on the level in these types of conditions but climbing won't work at all and steering can get very sketchy. You can decrease tire pressure to increase the footprint of the tires and increase flotation and performance but be aware that no tire can hold up to prolonged riding at very low air pressures and I've seen a lot of failed sidewalls and delaminated tire beads from doing just that.

    Oftentimes, it's possible to find an alternate line or route to hunt out those little pockets of firmer goodness and be able to ride without slowly destroying your tires. On beaches, the sand is firmer where it's still holding some moisture such as near the tide line. On snowmobile trails, the trail is loosest where the machine's track has rototilled the snow but it's often good riding if you can stay on the ski track, the proverbial "thin white line". A wonderful feature of snow is it's property of sintering, or packing down and becoming firmer after it's been disturbed so if you wait a little while after traffic, it usually gets firmer and much more ridable. Likewise, drifted snow can firm up into white slickrock dunes which make for incredible riding. If you're riding in a group, switching trail breaking duties will spread the burden out among your companions.

    An ironic thing, when I first started building FatBikes, I kind of intended them as a great equalizer for bigger, heavier riders because light people floated sooo much better on the SnowCat rims which were the current state of the art. And it worked great for a while but then smaller people started getting their hands on FatBikes and now guess what, we're right back to square one. In retrospect, I should have lobbied hard to enact laws to prevent this travesty. So yeah, being lighter is often a big advantage but then there are times that being heavier helps keep you from wallowing around as much as the lighter folks.

    Being able to adapt to challenging conditions is an innate part of the sport (can I call it a sport?) of Fat Biking. As you gain experience, you'll get much better at putting together micro lines to come up with a ridable route through seemingly impossible conditions and become adept at subtle weight shifts from front to rear to avoid bogging down.

    When worse comes to worse, just strap a wheel to each foot, and voila, snowshoes.
    Last edited by Wildfire; 03-11-2009 at 08:29 AM.

  4. #4
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    All time most asked Fat Bike question:

    "How come you don't put studs on those big tires for winter riding?"

    Contrary to popular opinion, most snow trails have pretty good traction because the big tires put a lot of surface area in contact with the snow. And even a lot of ice has decent traction, especially if it's flat and smooth, below freezing out, and/or there's a little windblown dust on it. You just have to ride smoothly over the ice stretches and not try any abrubt maneuvers.

    Most winter XC riding, at least around here in Alaska, is mostly on packed snow with short stretches of overflow or wind scoured ice. Adding studs increases rolling resisance drastically, so most riders opt to not use the studs and just be careful when crossing the occasional ice patches.

    There are times, though, when studded tires are life savers: rough, uneven ice, commuting, very slick ice with water on top of it, etc. I've had really good success using the 26 X 2.25" Nokian Fredie's Revenz tires on Large Marge rims. They are slow and sound like a freight train when you're riding, but traction is great, and they're big enough to offer good rim protection when hitting rocks or logs. Or if you have a spare set of 29er wheels for your Fat Bike, Nokian now has a decent 29er studded tire on the market. There's nothing like bombing down frozen class IV whitewater rivers or highmarking on icebergs which would be almost suicidal without studded tires. Just be careful, even studded tires have their limits.

    Here's some photos from the Knik Glacier. Everyone had FatBikes with studded tires.
    Attached Images Attached Images
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  5. #5
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    Per bighit's request...

    Fat Fork info:
    • The Pugsley 100mm hub fork is 447mm AtoC.
    • The Jones 135mm hub fork is 435mm AtoC with 55mm of rake. (Not good for suspension corrected 29er retrofits.)
    • The Vicious Snow fork is 450mm and they can't/won't do longer do to blade availability. (I talked to Carl at NAHBS about it.)
    • DeSalvo makes his snow fork at 460mm. Which is the longest "production" fork I could find. He also is limited by available blade length due to the Uni-Crown construction.
    • If you need a longer fork for a 29er retrofit, I think Walt can make custom lengths using his segmented fork construction. But of course it's custom ($'s) and he has a back log.

    There may be other builders who can make "Fat" forks. But these are the ones I've looked into and have done Fat forks before.

    jw
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    "And single-speeding 29ers are mountain biking's equivalent of Scientologists..." - Captain Dondo

  6. #6
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    Addendum

    Quote Originally Posted by GrumpyOne
    Per bighit's request...

    Fat Fork info:
    • The Pugsley 100mm hub fork is 447mm AtoC.
    • The Jones 135mm hub fork is 435mm AtoC with 55mm of rake. (Not good for suspension corrected 29er retrofits.)
    • The Vicious Snow fork is 450mm and they can't/won't do longer do to blade availability. (I talked to Carl at NAHBS about it.)
    • DeSalvo makes his snow fork at 460mm. Which is the longest "production" fork I could find. He also is limited by available blade length due to the Uni-Crown construction.
    • If you need a longer fork for a 29er retrofit, I think Walt can make custom lengths using his segmented fork construction. But of course it's custom ($'s) and he has a back log.

    There may be other builders who can make "Fat" forks. But these are the ones I've looked into and have done Fat forks before.

    jw
    The Wildfire FatFork is 465mm A - C without having to use a blade stretcher.
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  7. #7
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    I'll add a question that has been on my mind, why no competition for the Endomorph? Considering the amount of bikes being built up around this tire/platform, some other tire companies must be trying to develop something, right?

  8. #8
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    Rear triangle offset explained

    I'll try to tackle this one since somebody asked it on another thread:

    "What's the deal with the offset rear stays on some Fat Bikes?"

    Here's how the offset came about:

    -The tires and rims are much wider then a standard mountain bike. This required the use of a wider chainline so the chain wouldn't rub on the big tire and wear out the sidewall.

    -In order to get the wider chainline, it was necessarry to build the frame with a wider bottom bracket shell for use with a wider bottom bracket spindle. At the time, most MTBs used a 68 or 73 mm shell with a 113mm spindle. That wasn't wide enough to clear the tire so we had to use wider bottom brackets. After a couple generations to accomodate increasingly wider rims and tires, we ended up with a 100 mm shell and a 145 mm bottom bracket spindle. So that solved that problem but led to:

    -Okay, the front problem was solved but led to a dilemna on the other end of the drive train: how to carry the new wider chainline back to the rear hub? At the time, there were very few wider then normal hubs available so we had to figure out a way to move the cassette out further from the bike's centerline to match the wider front chainrings using the available 135mm wide hubs. We decided to create a "virtual wide hub" by offsetting the rear triangle 18 mm out toward the drive side which brought the cassette out in line with the front chainrings. So that problem was solved but led to:

    -Now that we offset the rear stays, how do we bring the rim and tire back in line with the bike's centerline? If you were to take a standard rear mountain bike wheel and stick it in the dropouts, it would not line up with the centerline of the frame, it would be way out of line toward the drive side. That led to drilling offset spoke holes toward the drive side of the rear rim to bring the centerline of the rim and tire back into alignment with the frame's centerline. This allowed the use of equal length spokes on each side for a nice strong wheel build. Problem solved, or was it?

    -Somewhere along the line, the 29er market started taking off and I realized that the FatBike geometry was almost identical to the 29er geometry. Why not build a spare set of 29er wheels to make the FatBike a versatile, year-round machine? Unfortunately, the 29er rims are skinny and do not allow much of an offset spoke drilling. I had fairly good luck using a Bontrager offset rim, but the offset spoke drilling was only a couple mms so in order to make everything line up, I had to use much shorter (3 mm) spokes on the non-drive side of the rear wheel to get everything to line up. Not ideal: the spoke tension was very tight on the nondrive side and very loose on the drive side. Some hubs had wider flange spacing and I was able to get them to work. I've been riding the same rear wheel for years with no problems, but again, it's not ideal. Which led to:

    -Ditching the rear offset and using wider hubs which have recently come on the market. With a 160 mm hub everything works out nicely for chainline. Yes, they are a little heavier though the Chris King is lighter then many top 135mm hubs. And for sure, they are more expensive then most 135mm hubs but look at it this way: it allows your FatBike to be used rear round so think of how much money you'll save by not having to have two different bikes. That's why I've kept the 465mm axle to crown length on the rigid fork allowing a summer swapout to a 29er suspension fork. Losing the rear offset has the added benefit of making the framebuilder's job a lot easier: much less chainstay and seatstay bending. And of course, summer 29er wheels build up nice and strong.

    So anyway, if all of the above didn't give you a massive headache to try to comprehend, that is the deal with the rear offset stays.
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  9. #9
    hellraiser
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    Thank you for the explanation - you cleared that up nicely.

    Love the look of your bikes BTW. The John Deer was my favorite.

    Coach
    eh?

  10. #10
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    What about adding images of all available snow rims with Pugsley and Arrow tires mounted on each? I think people would benefit from seeing what sort of tire profile they'll get before purchasing.

    I'm crushed about no more Gazz 3.0s. I needed those.

  11. #11
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    Rolling Resistance Q

    If I had a dollar for every time I heard this one...

    "With all that rotating weight, aren't fat bikes hard to pedal?"

    I think this has been my biggest hurdle to get people to buy FatBikes. I encountered a ton of skepticism and naysayers when the FatBikes came out and a lot of those were very experienced winter cyclists. Even with people now routinely winning just about every winter race out there with various brands of fat bikes, I still encounter this a lot.

    While it's doubtful that you will see Lance riding one in the Tour de France the things roll pretty darn good on softer surfaces. And surprisingly well on hard surfaces too (but I still swap out with 29er wheels in the summer).

    First of all, the Endomorph tread is just a bigger version of a semi-slick. Back in the Nokian Gazzaloddi/Remolino 80 mm rim days, we used to spend a lot of time shaving knobs off our treads to get them to roll faster. No need for that with the Endo.

    Second, rolling resistance of a bike goes up drastically when the tires are making ruts in soft stuff because the wheels are always trying to climb up out of their own tracks. The big tires make a lot shallower rut so rolling resistance is a lot less on fat tires then skinny tires. Also the big wheels track better with a lot less wallowing around in soft conditions which saves a lot of wasted energy.

    There are probably other theories out there why they roll so well so techy types, feel free to chime in if you have one.

    So roll on, fat bikes, roll on.
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  12. #12
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    Quote Originally Posted by fastale
    I'll add a question that has been on my mind, why no competition for the Endomorph? Considering the amount of bikes being built up around this tire/platform, some other tire companies must be trying to develop something, right?
    I'm going to bump my question because I think it's a good one.

  13. #13
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    Quote Originally Posted by fastale
    I'm going to bump my question because I think it's a good one.
    i wish there were more options. i think its because there is a small market right now.

  14. #14
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    Quote Originally Posted by bighit
    i wish there were more options. i think its because there is a small market right now.
    I'm hoping there will be some more options. I've heard a couple rumors but so far nothing else comparable has appeared on the market. It's probably just a matter of time until other manufacturers respond to the growing market.
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  15. #15
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    100mm bottom brackets

    the pugsley takes a 100mm bottom bracket. the only ones i know of are,
    FSA Platinum DH isis
    Truvativ Gigapipe DH isis

    the next question is, can you use any of the new external bottom brackets and cranks. they all list the bb shell as 68/73.

    you would need a longer axle on the cranks right?

  16. #16
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    Quote Originally Posted by Wildfire

    First of all, the Endomorph tread is just a bigger version of a semi-slick. Back in the Nokian Gazzaloddi/Remolino 80 mm rim days, we used to spend a lot of time shaving knobs off our treads to get them to roll faster. No need for that with the Endo.

    Second, rolling resistance of a bike goes up drastically when the tires are making ruts in soft stuff because the wheels are always trying to climb up out of their own tracks. The big tires make a lot shallower rut so rolling resistance is a lot less on fat tires then skinny tires. Also the big wheels track better with a lot less wallowing around in soft conditions which saves a lot of wasted energy.

    There are probably other theories out there why they roll so well so techy types, feel free to chime in if you have one.

    So roll on, fat bikes, roll on.
    A few years ago in Germany (where else...) some major bike mags decided to get to the bottom of rolling resistance once and for all. They kitted out several bikes with more wires than a spiderweb and went for it. I'm not going to translate all those articles (it's not my mother tongue for starters) and computer read-outs, but here's the gist:

    - it's not because it's got big, fat knobs that it rolls slower. Actually, some pretty agressive treads outperformed all semislicks on the market. Construction of the carcass is crucial to rolling resistance.

    - adding a tube increases rolling resistance x-fold. Friction between the tube and tire is responsible for that. Tubeless is the way to go.

    - the lower the tire pressure/wider the tire, the less rolling resistance on uneven terrain. Two reasons for that.
    First: a skinny, hard inflated tire presents a long, narrow footprint. A fat, underinflated tire presents a short, wide footprint. The latter has the least rolling resistance (don't ask me why, it's physics).
    Second: every pebble wants to stop a tire. A hard tire bounces over it, resulting in an upward movement and deceleration. A soft tire deforms and rolls over it without vertical movement, which results in less rolling resistance.

    - a heavier wheel takes more watt to accelerate, but once going pays dividends when the going gets rough. I forgot and am too lame to go look for the actual figures but I think it took like 5 extra watts to accelerate a heavy wheel vs a light one to 15 mph.
    But it took 20 watts extra per 200 yards to maintain that light wheel at that speed over rough stuff vs the heavier one.

    That pretty much sums up what we've all felt: a soft, fat tire is a drag on pavement but seems to accelerate when the going gets rough.
    Vs a skinny tire at mega psi: great when smooth, but hits a wall when hitting rough spots.

    And explains why our very fat tired bikes are faster on rough terrain than they appear at first sight.

    Another reason why fat bikes are so good on rough stuff is the rotational force. If you want to experience it, grab a spinning wheel by both hub ends and try to turn it. It's difficult and it's a main reason why we stay upright on a two-wheeled contraption.
    A heavy wheel generates more force than a light one and very much wants to keep in the same plane when spinning. Slippery roots or rock gardens don't impress heavy wheels as much as lighter ones.

    So don't follow skinny tired folk on their terrain... try to lure them onto yours

  17. #17
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    Quote Originally Posted by bighit
    the pugsley takes a 100mm bottom bracket. the only ones i know of are,
    FSA Platinum DH isis
    Truvativ Gigapipe DH isis

    the next question is, can you use any of the new external bottom brackets and cranks. they all list the bb shell as 68/73.

    you would need a longer axle on the cranks right?
    It's beyond just ISIS at this point. I just ordered a Race Face Atlas FR with a 100 mm spindle for mine. How could I not? It's available in purple now....

    The Surly Mr. Whirly is available in a 100mm option too. So yep, the external bearing BB's are a workable option too.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  18. #18
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    Phil Wood 100mm BB too, square taper

  19. #19
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    What he said.

    Great explanation which runs contrary to a lot of conventional wisdom.

    "
    Quote Originally Posted by caminoloco
    A few years ago in Germany (where else...) some major bike mags decided to get to the bottom of rolling resistance once and for all. They kitted out several bikes with more wires than a spiderweb and went for it. I'm not going to translate all those articles (it's not my mother tongue for starters) and computer read-outs, but here's the gist:

    - it's not because it's got big, fat knobs that it rolls slower. Actually, some pretty agressive treads outperformed all semislicks on the market. Construction of the carcass is crucial to rolling resistance."

    Not quite convinced on this point, shaving all the knobs except the outer row on the old Nokian Gazzaloddi 3.0 tires made them noticeably faster. I agree that supple sidewalls make tires faster on soft and uneven surfaces.

    "- adding a tube increases rolling resistance x-fold. Friction between the tube and tire is responsible for that. Tubeless is the way to go."

    So far all the attempts I've heard about to make a winter tubeless setup for the big tires and rims at low air pressures in the cold have failed. If somebody could figure that one out it would be a big breakthrough.

    "- the lower the tire pressure/wider the tire, the less rolling resistance on uneven terrain. Two reasons for that.
    First: a skinny, hard inflated tire presents a long, narrow footprint. A fat, underinflated tire presents a short, wide footprint. The latter has the least rolling resistance (don't ask me why, it's physics)."

    I think it has to do with how far the tire is sinking into the snow. Short and wide could be compared to a rolling pin on dough, long and skinny is more like a pizza cutter.

    "Second: every pebble wants to stop a tire. A hard tire bounces over it, resulting in an upward movement and deceleration. A soft tire deforms and rolls over it without vertical movement, which results in less rolling resistance".

    Amen.

    "- a heavier wheel takes more watt to accelerate, but once going pays dividends when the going gets rough. I forgot and am too lame to go look for the actual figures but I think it took like 5 extra watts to accelerate a heavy wheel vs a light one to 15 mph.
    But it took 20 watts extra per 200 yards to maintain that light wheel at that speed over rough stuff vs the heavier one."

    That's interesting.

    "That pretty much sums up what we've all felt: a soft, fat tire is a drag on pavement but seems to accelerate when the going gets rough.
    Vs a skinny tire at mega psi: great when smooth, but hits a wall when hitting rough spots.

    And explains why our very fat tired bikes are faster on rough terrain than they appear at first sight.

    Another reason why fat bikes are so good on rough stuff is the rotational force. If you want to experience it, grab a spinning wheel by both hub ends and try to turn it. It's difficult and it's a main reason why we stay upright on a two-wheeled contraption.
    A heavy wheel generates more force than a light one and very much wants to keep in the same plane when spinning. Slippery roots or rock gardens don't impress heavy wheels as much as lighter ones.

    So don't follow skinny tired folk on their terrain... try to lure them onto yours
    "

    Thanks.
    Owner, Trailwerx Trails Contracting
    Palmer, Alaska
    www.trailwerx.com

  20. #20
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    Where?

    [QUOTE=MendonCycleSmith]It's beyond just ISIS at this point. I just ordered a Race Face Atlas FR with a 100 mm spindle for mine. How could I not? It's available in purple now....

    Where does one order the 100mm Atlas? thx.

  21. #21
    All Lefty's, all the time Moderator
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    Quote Originally Posted by Stroganof
    Where does one order the 100mm Atlas? thx.
    I'm pretty sure Quality Bicycle Products has them, I got mine direct from RF, through an industry only offer.

    I know they will sell to your local shop too.

    Shouldn't be too hard, easy enough to order, but I doubt too many store will have one sitting about on a shelf, correct me if I'm wrong....
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



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  22. #22
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    Frame tire clearance information for two different Surly Pugsleys:

    With an Endomorph mounted on a Large Marge rim, I put a little piece of tape on the chainstays and seatstays at the point where the tire side of the tire comes closest to the stays, then removed the wheel and measured the inside-to-inside distance between the stays at the point where the tire passes. On the Pugs, the widest point on the chainstays is well forward of where the tire passes for some reason.

    Here is an example of where I determined I would measure the Pugs. The little black double arrow indicates the closes point between the tire and chainstay and this is where I stuck the piece of tape:



    First, on a size small Pugs, I marked the spot with tape and I then pulled the wheel and measured just shy of 113 mm inside to inside on the chainstays:



    The seatstays were 115 mm:



    On a size medium older Pugs (purple), I got the following numbers (which were within 1mm of the other Pugs).

    Chainstays 112mm where the tire passes:



    Seatstay 116mm:



    For comparison's sake:
    Quote Originally Posted by pbasinger
    Yesterday I had the opportunity to measure a larger sized [aluminum] 907 in the method described by tscheesy an got 111 mm top and bottom.
    Quote Originally Posted by bflemin
    Here are measurements we made of the chain stay/seat stay widths on the 9:ZERO:7 ti and aluminum models. For the aluminum 907, we measured widths of 111mm at the seat stays and 110 mm at the chain stays. On the titanium 907, we measured 125 mm at the seat stays, and 121 mm at the chain stay.
    Quote Originally Posted by Wildfire
    Tire clearance [on the 2010 Wildfire FatBike chromoly frames] at 320 mm radius (point of maximum width of tire) from the axle is 111 mm on the chain stays and 116 mm at the seat stays.
    And finally some Surly Endomorph 3.7 effective tire width numbers originally posted by pbasinger. The Endomorphs were mounted on the rims listed below and inflated to 10psi:

    • Speedway 70mm rim with Endomorph: 94.5 - 95.5 mm
    • Vicious Cycles 80 rim with Endomorph: 95.5 - 96.5 mm
    • 100mm rim with Endomorph: 106.5 - 107.5 mm
    Last edited by tscheezy; 11-11-2009 at 12:29 AM.
    My video techniques can be found in this thread.

  23. #23
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    Does a 24"X3" qualify as a Fat Bike? Some Felt cruisers are sold with 24X3.
    Seems that fitting a 24X3 to an MTB frame designed for 26X2 would be simple.
    "I don't suffer from insanity!I rather enjoy it."

  24. #24
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    Caution;  Merge;  Workers Ahead! 100mm BB/crank options

    That's a short list of the 100mm BB & cranks options:

    Phil Wood square JIS BB with some square cranks










    FSA Platinum Pro DH or Truvative GigaPipe Team DH ISIS BB with some ISIS cranks









    Race Face Atlas FR & Diabolus DH cranks/BB sets





    Profile Racing BMX cranks/BB set





    Truvativ Howitzer Team BB with some Truvativ cranks with Howitzer interface








    Surly Mr.Whirly cranks with some external bearing BB




    The Hive 15G cranks/BB set





    It's maybe helpfull
    Last edited by velopax; 01-06-2010 at 02:46 AM.
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  25. #25
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    Quote Originally Posted by wheelbender6
    Does a 24"X3" qualify as a Fat Bike? Some Felt cruisers are sold with 24X3.
    Seems that fitting a 24X3 to an MTB frame designed for 26X2 would be simple.
    I think this was the point that Surly was trying to make with the Rat Ride 1x1=11 Anniversary bike. It's got slick Hoggy g 24x3.5 tires as stock equipment on 24 inch Large Marge rims.

  26. #26
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    Yep. Either that or a 1X1 built up as a Mini Pugs could be called a Poor Man's Fat Bike. There is no need to get a specialized Fat Bike when you can do the same thing with a generic MTB that will also allow you to run conventional MTB tires most of the year.

  27. #27
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    I've spent lots of time on Snowcat rims with 2.5 inch Diesel Pro's on a regular mountain bike and there is no comparison to a real Fatbike. If you can find a fatbike in your budget you will not regret it.

  28. #28
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    I'd maintain a Fat Bike built up with more affordable components is a real Fat Bike. Until you've tried a 1X1 Fat Bike, don't knock it.

  29. #29
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    fyi: niner carbon fork (the 550 gram one) fits a 3" gazzi on a sun s-type rim.
    don't have an endo but doubt it'd work, but for half-fat folks... there you go, lightest fatty fork around.

    edit: oh! just notice the profiles up there, reminded me; i had top grab aftermarket cups for my profiles, decided to try them without the spacers, lspaced the cups furthest out (to simulate wide bb)- they measured out a smidge over 90mm wide.
    I think with those lower profile cups and the arms a couple mm out from fully pressed on you would get the bb cups spaced out for 100mm easily.
    If steel is real then aluminium is supercallafragiliniun!

  30. #30
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    Quote Originally Posted by byknuts
    fyi: niner carbon fork (the 550 gram one) fits a 3" gazzi on a sun s-type rim.
    don't have an endo but doubt it'd work, but for half-fat folks... there you go, lightest fatty fork around.

    edit: oh! just notice the profiles up there, reminded me; i had top grab aftermarket cups for my profiles, decided to try them without the spacers, lspaced the cups furthest out (to simulate wide bb)- they measured out a smidge over 90mm wide.
    I think with those lower profile cups and the arms a couple mm out from fully pressed on you would get the bb cups spaced out for 100mm easily.

    edit numero dos: shaved the side knobs down on the gazzi, fits in a fox talas fork now.
    mud clearance is on the short side, but the notion of 3" of tire under 5" of fork was too intriguing for me not to try it. it's an older talas too, not the nifty new 140mm guys, they might be even easier to work with.

    scratch the previous: it WILL work, but you have to shave the center knobs down to a very minimal height. (think endomorph tread depth) which quite frankly for a front tire makes no sense.
    so as much fun to look at as it may be it's not REALLY going to work for anything but beach duty.
    fits just fine in a fox 36 though.
    Last edited by byknuts; 08-08-2010 at 10:32 AM.
    If steel is real then aluminium is supercallafragiliniun!

  31. #31
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    What about recommended tire pressures?

    Snow v. Sand v. Hardpack?

    I suspect the snow answer will depend on the type of snow (fluffy, wet, heavy, etc.)?

    Thanks

  32. #32
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    New question here. frame offset

    hi,

    might be asking an old question, but here goes

    if running single speed/hub gear and fat tire could you work something with an 83mm BB and a non offset rear triangle

    only asking as my surly 1x1 got damage by a car and needs rear triangle repairing, and the car driver insurance is paying for the repair (tried for a new frame but not having it )

    thanks for your help


  33. #33
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    Gyroscopic effect of all that mass? We don't have much snow here in WA but, I would like to toy around with a Pugs.
    Isaac

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    Salsa Enabler Fork questions

    Q: What is the required hub/brake setup on the Enabler?
    A: The Enabler is designed to use a standard 135 mm spaced, 10 mm axle rear hub (cassette, single speed, ect) and a standard front IS mount disc brake*.

    Q: Can I use a 135 mm spaced FRONT hub (Paul, Fatback/Hadley) in an Enabler fork?
    A: No. The brake rotor will be too close to the IS disc tab, and the 9 mm axle ends will be too loose in the Enabler's 10 mm dropout slots. Modifications could be made to make it work, however.


    *A word on IS mount dimensions.
    For the most part, most "front" and "rear" brake calipers are identical. Front and rear caliper adapters, however, are different dimensions, because the IS radial dimensions are different front to rear.
    The IS axial dimensions (distance from IS mounting tab to the rotor mounting surface of hub) are the same front to rear. However, the IS dimensions from the axle end/dropout surface (not the IS tab) to the rotor mounting surface of the hub is 10 mm in the front and 15 mm in the rear. This is why a 135 mm spaced front hub won't work in an Enabler; the brake rotor will be 5mm too close to the fork's IS tab.

  35. #35
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    Surly Pugsley forks

    Surly offers the Pugsley fork in three variations: Symmetrical with 100 mm axle spacing, symmetrical with 135 mm axle spacing, and offset with 135 mm axle spacing (the original Pugsley fork).

    The 100 mm non-offset fork uses a standard 100 mm front hub, and requires a front brake caliper adapter.

    The 135 mm non-offset fork uses a standard 135 mm REAR hub, and requires a front brake caliper adapter. This is the same setup as the Salsa Enabler fork.

    The 135 mm offset fork uses a 135 mm REAR hub, and requires a REAR brake caliper adapter.

    Trying to use a 135 mm front hub (Paul, Speedway, ect.) in either of the 135 mm spaced forks will encounter the same problems as mentioned in the above post on the Enabler fork (brake rotor spacing and axle diameter).
    Last edited by Andy FitzGibbon; 07-06-2011 at 04:40 PM.

  36. #36
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    135 mm front hubs

    The Paul WHUB and the various offerings from Fatback (Hadley and import) are all true 135 mm FRONT hubs. They have 9 mm axle ends and front disc rotor spacing, just like a standard 100 mm front disc hub. These hubs will work in Fatback forks and the 907/White Bros SnowPack fork. They won't work in the Salsa Enabler or either of the 135 mm Pugsley forks without modifications.

    Surly's New Disc 135 mm front hub is actually just a rear hub without freewheel threads. So, it has 10 mm axle ends and rear disc rotor spacing. This hub will work in the Salsa Enabler or either of the 135 mm Pugsley forks, but won't work in any of the Fatback forks or the 907/White Bros. Snowpack fork without modification.

  37. #37
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    I just bought a SALSA MUKLUK two months ago. I put it together with a bike mechanic-friend of mine and hit the trails. The terrain here in southwestern Manitoba is relatively flat (Canadian prairie) and sandy. I was out on the sandy trails about a month ago, and experienced some chain suck in the wet sand. I've had chain suck before, but this time seemed much worse. I was able to keep going, but I noticed things just didn't "feel right". When I got home, I examined my drive train and noticed my middle chain ring was bent in a couple of different places and there were slivers of metal poking out from the sides of the teeth in the chain ring where the chain had sheared into the metal of the chain ring.

    My mechanic friend hasn't seen it yet, but he says that we might be able to file the slivers off between the teeth and try to straighten out the chain ring.

    Has anybody else experienced this before? I don't think it's just because it's a fat-tire bike, but I haven't had it that bad on my other bikes.

    Should I stock spare middle chain rings? Should I keep separate drive trains for winter and summer?


    Steve
    (ironbirdexplorer)

  38. #38
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    I'm planning to build "fatbike" based on the Troll frame and 26x3.0 tires ( duro leopard or gazzaloddis ), for autumn-winter-spring riding ( and to swap wheels to 700c for summer commuting ). So I decided to ask here. Not going for true fatbike, because I just dont have a place for three bikes ( now paragon 29er + commuter rigid, which frameset will be changed to Troll )

    How critical is rim width ? Is it absolutely necessary to use widest rim possible ( large marge, 65mm ) ?
    Or it will be almost identical with 47mm trial rims ? It is a matter of money, i can get 47mm rims almost 4 times cheaper , than 65mm marges...

    Will I be able to use non offset large marge rims on standart slx hubs wheels ( front 100mm and rear 135mm ) on true fatbike frameset ?

  39. #39
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    Tire Weights and Widths

    Surly Big Fat Larry 26x4.7
    Weighs: 1433gr (120tpi)
    Measures:
    65mm Rim-98mm-100mm
    80mm Rim-104mm
    100mm Rim-113-118mm

    Surly Larry 26x3.8
    Weighs: 1530gr (27tpi) 1400gr (120tpi)
    Measures:
    65mm Rim-92mm
    80mm Rim-96mm
    100mm Rim-105mm

    Surly Endomorph 26x3.7
    Weighs:
    Measures:
    65mm Rim-92mm
    80mm Rim-
    100mm Rim-

    Surly Nate 26x3.8
    Weighs: 1637gr (27tpi) 1530gr (120tpi)
    Measures:
    65mm Rim-96-98mm
    80mm Rim-
    100mm Rim-

    Surly Black Floyd 26x3.8
    Weighs: 1237gr (27tpi)
    Measures:
    65mm Rim-
    80mm Rim-
    100mm Rim-

    Rims:

    Surly Large Marge 65mm
    Weighs 1150g (DH), 950g (XC)

    Surly Rolling Darryl 82mm
    Weighs 1030g (solid) 850g (drilled)

    Flattop 100mm
    Weighs 1150g (solid), 950g (drilled)

    Flattop 80mm
    Weighs 980g (solid), 795g (drilled)

    Vicious Cycles Graceful Fat Sheba 80mm
    Weighs 1310g

    Credits: benwitt11, FTMN, mikesee, Andy FitzGibbon, wadester

    I'm trying to complete this table, so if you have a missing piece please PM me. Thanks!
    Last edited by JAGI410; 09-13-2011 at 07:33 PM.
    Jason
    Disclaimer: www.paramountsports.net

  40. #40
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    Great job with the table. Exactly the information that I was looking for with the new and current tires. Thanks. Also, I currently am running my larry 3.8s tubeless on 47mm trial tech rims for summer. They both measure 88mm.
    Last edited by EPcycles; 08-28-2011 at 08:13 PM.

  41. #41
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    My weights are similar...

    BFL. 120 tpi 1420 gr
    Nate. 120 tpi 1520 gr
    Larry. ? 1480 gr

    Very interesting that the BFL is lighter than the skinny Larry.

  42. #42
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    On post #24 there is this information

    Speedway 70mm rim with Endomorph: 94.5 - 95.5 mm
    Vicious Cycles 80 rim with Endomorph: 95.5 - 96.5 mm
    100mm rim with Endomorph: 106.5 - 107.5 mm

    Found it when looking for endo widths

  43. #43
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    Surly now offers two different Mr. Whirly spindle lengths for 100 mm bottom bracket shells:

    Pugsley: 157 mm
    Moonlander: 171 mm, includes spacers to take up additional space between crankarms and bottom bracket cups.

    The Moonlander spindle is longer so that the crankset's chainline will match up with the 28 mm rear offset. But, it could easily be used on other bikes to deal with crankarm or tire/chain clearance issues.

  44. #44
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    tire weights, additional

    very slightly worn Endomorph 3.7, unknown tpi = 1330g

    Larry 3.8, 120 tpi = 1430g

    Larry 3.8, 27 tpi = 1500g

    weighed on Alpine hanging digital scale.

  45. #45
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    Please, please read..

    Hello all,

    I am carrying out initial market research for my Final Year Project for my BEng Mechanical Engineering Degree at the University of Hull. I would be incredibly appreciative of any response and questions you may have. I am very new to the idea of FatBikes so please if I am stating incorrect information please correct me. My supervisor at the University of Hull has given me the following task:

    A new generation of off-road bike, so called 'FatBikes' utilise large (100mm wide) tyres running at relatively low pressures (5-20psi) to handle soft terrain like snow, mud and sand. Conventional portable bicycle pumps are designed to deliver low volumes of air at high pressure (60-120psi). Fatbike tyres are relatively easy to puncture and cyclists are faced with an onerous task to repair and re-inflate them when 'on the trail' due to their relatively large volumes. Additionally cyclists like to 'tune' the running pressure to the terrain, and therefore some means of measuring the absolute pressure accurately is required. The scope of the project is to design and evaluate a low-weight, highly portable, manufacturable solution to this issue. There is no preferred conceptual solution, the project should include a widely ranging survey of air-pumping technologies.

    Adding to this, im hoping to manufacture a prototype and then test it.

    Firstly can anybody suggest any pumps on the current market and/or send me a link to the relevant websites?

    Sounds obvious but do FatBike tyres have an inner tube and is the value on this inner tube the same as a conventional bike tyre?

    Many, many Thanks

    Dave

  46. #46
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    [QUOTE=daveyboy150;8523581]Hello all,
    Firstly can anybody suggest any pumps on the current market and/or send me a link to the relevant websites?
    Any standard mechanical portable pump cycling will work. Look at Topeak, Blackburn, Lenzyne, Portland Design Works etc. Google them. Also, portable CO2 powered "insta-flate" style gas canisters can work too though big tires need multiple compressed gas tubes to get them up to adequate pressure.

    Sounds obvious but do FatBike tyres have an inner tube and is the value on this inner tube the same as a conventional bike tyre?
    Most fat tire bikes use butyl rubber inner tubes. They are larger in volume due to the larger tire size. They typically use either Presta ("French") or Shraeder ("automobile style") valves. Some enthusiasts have experimented with tubeless style setups similar to those used in conventional MTB tires, though the rims and tires available for fatbikes are not tubeless specific, meaning the tire casings are not sealed and the rims do not have double wall sealed construction and the tight beads as seen n conventional MTB tubeless systems. Some fat bike users will put tubeless tire sealant (Stan's No Tubes) in to the innertube to help seal the inner tube against small punctures from thorns if riding in sandy, desert type conditions.

  47. #47
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    thank you very much for this information, I will be using this for my research.

    Dave

  48. #48
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    Ps are there any websites that give clear details on the tyres / inner tubes so that I can reference this in my report?

    Many thanks

  49. #49
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    regular MTB bike and 65mm rims,

    thinking it should fit, got a giant reign bike,
    and 2.5 tires fit.
    so what about some large marge 65mm wheelset ?
    and where to get 15QR front ?

    other than that, would like some studded tires,
    at least in the front. do have nokian, but they seam skinny ?
    any options ? or tools to do some kendas ?
    cheers, Rob

  50. #50
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    Could'nt quite decide wether this or the demo....sticky, was the correct thread for this. So I'v just gone for this one.

    Fork lengths for the various fat frames?
    There seems to be two main lengths. ~450mm ATC, and ~470mm ATC. But browsing the various stores/sites, its seems difficult to track down which frame is designed for which. I like the idea of a shorter front end, because I myself am short, so it aids fit. But the option to swap to a suspension fork, is a nice piece of versatility. Could people please fill in the gaps, and apols if this has been covered (I could'nt find it).

    Salsa Mukluk - ATC = 468mm
    Surly Pugsly - ATC = 447mm
    Surly Moonlander - ATC = 447mm
    Alu 9zero7 - ATC = ???mm
    Alu fatback - ATC = ???mm
    Sandman Gobi - ATC = ???mm
    On-one - ATC = ???mm

  51. #51
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    Bureau of Weights & Measures, Fatbike Division

    Rolling Darryl rim, in Surly's limited edition lime green finish: 870g

  52. #52
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    What the heck is it and where can I get one?

    The other day I was riding in Caspers on Westridge and a guy came through the gate from Coto De Caza on a crazy looking bike with tires that were about 12" wide and only about 2/3's the height of a normal tire. they looked like tires off a dune buggy.
    The fat tire bikes I see on the forum have much taller wheels that aren't as wide.
    What the heck is this bike? Where can I get one or at least learn more about them?

  53. #53
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    Anaerobic, I believe you're thinking of a Hanebrink.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  54. #54
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    Quote Originally Posted by Drew Diller View Post
    Anaerobic, I believe you're thinking of a Hanebrink.
    Pretty cool

    Gallery - Fortune Hanebrink

  55. #55
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    Yes, that is what it looked like as far as the tires and wheels, but does that mean it was an electric bike? The bike I saw was a rigid frame, no suspension. Do they make a non-electric version?

  56. #56
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    Couldn't tell ya. I think you want the Fat Bike History thread, or put in an inquiry to the current company.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  57. #57
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    Quote Originally Posted by Wildfire View Post
    While it's doubtful that you will see Lance riding one in the Tour de France the things roll pretty darn good on softer surfaces. And surprisingly well on hard surfaces too (but I still swap out with 29er wheels in the summer)
    Isn't the OLD longer on a fat bike rear than standard MTB wheel?
    A garage full of steel frames means happiness.

  58. #58
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    what are pros and cons of aluminum, steel, and titanium frames for fatbikes? Which is best for snow and sand riding?

  59. #59
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    Quote Originally Posted by CS2 View Post
    Isn't the OLD longer on a fat bike rear than standard MTB wheel?
    If you have a non-offset frame. You can build a 29er wheelset, with the wider hubs.
    A big boy did it, and ran away.
    62*28'

  60. #60
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    I have a 2011 White Pugs that came standard with Large Marges on Deore hus. Anyone know which front gear style cog we are suppose to use for it? Fixed or Freewheel only?

    I bought a 22t Surly fixed cog but after installing it, realized that there is no reverse thread for a locknut.

  61. #61
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    Innova Spider:

    80-82 mm on doubletrack
    approx. 96 on sheba.

  62. #62
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    Quote Originally Posted by griplimited View Post
    I have a 2011 White Pugs that came standard with Large Marges on Deore hus. Anyone know which front gear style cog we are suppose to use for it? Fixed or Freewheel only?

    I bought a 22t Surly fixed cog but after installing it, realized that there is no reverse thread for a locknut.
    Anyone.

  63. #63
    ebnash
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    How come no one seems to run Hydraulic Brakes on Fat Bikes???

  64. #64
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    Quote Originally Posted by ebnash View Post
    How come no one seems to run Hydraulic Brakes on Fat Bikes???
    Those using their fatbike as a snowbike. Might be using the bike in temperatures cold enough to thicken the fluid. Hydraulics use two different oils. One of which thickens at a far lower temperature, DOT4. Hope tech use DOT4, and I'm planning on running them. In theory mechanical discs can be effected by ice build-up too. So there's no silver bullet.



    Freezing point for DOT 4 is -75F(-59C)

    Freezing point for mineral oil: -30F(-22C)
    A big boy did it, and ran away.
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  65. #65
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    I killed a pair of Hayes brakes due to beach riding, the pistons seized solid

    'Generally' cable discs are less prone to these problems, but YMMV
    A Fatback'd Lefty for who life IS a Beach

  66. #66
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    Quote Originally Posted by Dr Feelygood ! View Post
    I killed a pair of Hayes brakes due to beach riding, the pistons seized solid
    I had a similar experience last winter with the pistons on my Hayes MAG XC not wanting to retract after being exposed to road salt. I've since rebuilt them and put them on a different (non-winter) bike and they're back to their old bombproof selves.

    Trying out some BB5 calipers on the snow bike this year...

  67. #67
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    Neither system is completely foolproof in all conditions. I've used both and returned to BB7's for ease of adjustment. I'd rather use a 60/wheel brake in freeze/thaw/salt/ice/sand than trash a pretty set of expensive hydros.

    The upside with mechanical brakes is trail side service if/when something happens.

    Sure, you may have to pull the cable and warm up over your stove or with a lighter (you do have an E kit with you don't you?) to remove ice. You can also slide the warm cable into the housing to melt any buildup and then blow out the water.

    Also, you can find brake cables and housing almost anywhere if you absolutely need to replace.

  68. #68
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    Quote Originally Posted by ebnash View Post
    How come no one seems to run Hydraulic Brakes on Fat Bikes???
    I ran some old Hayes hydraulics last year as I had them kicking around and they had an extra long Goodridge hose on the rear brake, which was needed for my Mukluk due to the long run for the rear brake. I was riding in snow and temps down as low as -30. No issues with the fluid, though the front piston seized, I suspect from road salt from carrying the bike on a roof rack.

    This year I have installed some Formula K18's, had DOT5 put in them and installed Goodridge lines again. They are bomber so far but we've been riding is temps between zero and +10 degrees C so far. I'll also be transporting the bike inside my vehicle this year as well as I found the road salt from road spray did cause some corrosion inside my shifters which I think caused an early death for the first one.

  69. #69
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    Holiday Fat

    Larry 3.8 with white "120 tpi" sidewall markings- 1630g (+200g from an earlier Larry 3.8/120)

    three Surly 26x3.0-4.0" inner tubes, 1.3mm thickness- 450/450/470g

  70. #70
    Rippin da fAt
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    A friend of mine rides his Pugsley year round. He street sessions, trail rides and even occasionally rolls thru the skate park. I rode his Pug and found it to be a problem...Now I highly desire one!
    He says the Pug being a single speed makes you strong fast.

  71. #71
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    Whats the external diameter of a BFL on a 80mm rim?

    Calcs say its approaching 800mm. But that doesnt sound right.
    A big boy did it, and ran away.
    62*28'

  72. #72
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    Frame / Pack Pump

    I'm looking for a frame / pack pump to carry with me. Any suggestions? The one I've always used for my mtb doesn't work to well with the Larry's and Nate's

  73. #73
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    Quote Originally Posted by bobkorn View Post
    I'm looking for a frame / pack pump to carry with me. Any suggestions? The one I've always used for my mtb doesn't work to well with the Larry's and Nate's
    Don't know if this will help, but I use a Topeak Mtn Morph on 2.4 & 2.7.
    I realize they are nothing like Larry's or Nate's tho' you are going low pressure!

    BTI | products matching "pump" (page 9)

    Hope this helps!

  74. #74
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    Quote Originally Posted by BansheeRune View Post
    Don't know if this will help, but I use a Topeak Mtn Morph on 2.4 & 2.7.
    I realize they are nothing like Larry's or Nate's tho' you are going low pressure!


    Hope this helps!
    THANKS! Just ordered one.

  75. #75
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    No worries, I hope it serves you well. I have had mine several years now and still going strong.
    I run 2.7 at 18-28 psi. Its nice to be a beanpole.

    Btw how's the fatbike ride?

  76. #76
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    Quote Originally Posted by BansheeRune View Post
    No worries, I hope it serves you well. I have had mine several years now and still going strong.
    I run 2.7 at 18-28 psi. Its nice to be a beanpole.

    Btw how's the fatbike ride?
    It's a stock Pugsley and it's the best thing ever! I've been riding a 22 lb Ted Wojcik hard tail for 16 years and I am faster and climb just as well on the Pugsley. Can't say enough good things about it. I'd say once you go FAT, you'll never go back.

  77. #77
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    Sweet. I am torn between a Mukluk & a Pug. The other thing is sorting out the financial aspect.
    Lbs (Gear Exchane) aka the Soul Shop has both.
    Nothing like sorting it out!

    Tahnks

  78. #78
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    Quote Originally Posted by BansheeRune View Post
    Sweet. I am torn between a Mukluk & a Pug. The other thing is sorting out the financial aspect.
    Lbs (Gear Exchane) aka the Soul Shop has both.
    Nothing like sorting it out!

    Tahnks
    From what I've read, most feel the Pug handles more like a mtb, I agree and I think it looks better too. As they say about the money, "you're already a thousand over budget, so what's the big deal."

  79. #79
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    So much for hitting the budget!
    I am considering micro drive single speed. I need to test ride on single track as well as urban.
    I will go to the snow insurance agency and buy a policy before I test ride. Er uh wash my vehicle.
    Only then will we get some snow!

  80. #80
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    Hi all, read a lot around here but this is first post, and can't post a new thread, so may be asking a few silly question.
    Is there a horizontal dropout 170 fat bike frame out there?
    I just had a brainwave if there was, I could symmetric lace a 100mm rim to a centred (custom spacers) 135 alfine 8 IGH centering.
    Would this give equal spoke tension, the only potential benefit? (ignoring 29er use potential)
    If there's benefit in it, and no frame like that, I'm thinking a 9zero7 170 aluminium frame with QR dropouts cut and shut with custom horiztonal dropouts.
    My goal is a relatively simple/resilient fat bike on the outside, obstacle protection of a single speed, and road/trail speed range benefit of an internal geared hub.
    I'm also unsure about the right frame size (S) that matches my other bikes in measurements, or the bar pushing walking bike in deep sand testicle room of the XS standover height with extra 1.3" (135mm).

  81. #81
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    For a 170mm frame you'd need to replace the Alfine axle

    What's wrong with the 135mm frame?

  82. #82
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    For a 170mm + Alfine setup - which hasn't been done yet - you'd also need some additional mechanical solution for the chain line, which is a very skinny 47mm with cog flipped outward.

    Hey so how does this thread get managed anyway? I'm guilty of this too, but the relevance of FAQ-quality questions has really gone downhill over the length of it.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  83. #83
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    cheap entry IGH options available now

    Thanks, axle length obviously critical for the IGH to fit, doh!
    170 only reason/benefit seems to be idealistic symmetry for spoke life beating wheels in all terrain, and 29er swaps.
    For horizontal dropout and IGH, forgetting 29ers, I've since looked wider than 9zero7 and Fatback to find the heavier 26x4" budget entry level fat sand bikes more from beach cruiser approach than MTB, with horizontal dropouts, IGH.

    Origin8 has a Nuvinci hub offering (not my pref), related brand Sun Spider with beach cruiser styling Sturmey Archer kickback coaster brake single speed rear hub both same 4" Deton8er tyres. My pick for the apparent longer wheelbase and Nexus/Alfine options is the Fat Sand Bikes by TommiSea.
    Sun Spider seems best bang for buck cheap entry, $700 to try a fat bike, and a couple of ratios. I've come off a single speed commuter that I wanted that hub in, before the bike was decommissioned, so am a fan all over.
    Fat Sand Bikes have fixed and single speed versions with Fixi/Cruiser levels of budget entry appointments (or lack of) front brakes optional. They do a $3k Titanium Alfine 11 version too.
    Heavier and lower spec than the Surly/Salsa alternative front runners like Fatback and 9zero7.

    This is all in other threads but hopefully a digest in this reply is a helpful summary to cheap entry "IGH now off the shelf" folks. Anyone know other options?

  84. #84
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    This may be a silly question however I can't find the answer... Is it possible to use a standard mountain bike frame to build a fat tire bike? If not then what do I need to do to build this awesome creation... I'm new to the fat bike community. The plan is for a fully rigid fat bike. Thanks!

  85. #85
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    Quote Originally Posted by Twitchbone View Post
    ... Is it possible to use a standard mountain bike frame to build a fat tire bike?...
    No. There is not enough width or height in a standard frame for a tyre that may be between 88mmm - 110mmm.

    You could go half-fat though. This is done by putting a fat front fork and fat wheel on a standard bike. This is better done to a 29er frame because it does not change the geometry so much (but that depends on your frame).

    There's been a lot of half-fat builds on this forum, so a search may give you a few different ideas.
    As little bike as possible, as silent as possible.
    Latitude: 57º36' Highlands, Scotland

  86. #86
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    Thanks velobike... I figured it had to be a bigger frame just wasn't sure...

  87. #87
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    What gearing do you run on a single speed fat bike and what kind of terrain do you use it on? I want a SS fat bike but need info on gearing.

    richardh

  88. #88
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    Quote Originally Posted by rich-hud View Post
    What gearing do you run on a single speed fat bike and what kind of terrain do you use it on? I want a SS fat bike but need info on gearing.

    richardh
    I asked that very question here earlier this week
    If you need me I'll be at the bar

  89. #89
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    Seeing as this is the FAQ, I'll put my opinion in here as well.

    If you are already running a SS29er and will be riding the same tracks, you can use the same gearing if you are on the Larry or Endo. If you put Nates on, then you'll feel the extra grip in the form of resistance so a lower gear may be necessary, but you'll love them on soft stuff. I can't speak for the HDs because I haven't got any yet.

    If you put Floyds on, then you can raise your gearing IMO almost to where you'd have it on a SS cyclocross bike - with the same limitations on grip as the cx bike - but with more comfort and better ability to steamroller over rocks. (Floyds + fatbike = replacement for what I use my cx bike for).

    If you drop your tyre pressures below norm then again lower ratios help.

    However, the big advantage of fat tyres is the ability to go into places you couldn't ride with your normal bikes. That equals lower gearing, and often radically lower. Once you're riding like that, the next step is the BFLs for more flotation/steamroller effect and venturing into even odder places, and you are looking at crawler type ratios.

    When you have very low gearing then you have a problem with the rest of your riding, eg when you're not on the soft stuff your legs will be spinning like mad. Most of us can maintain a decent hardpack speed on 32/18, but it's difficult on 22/22, and yes, you'll want that gear if you exploit your fatty properly.

    Like many dedicated SSers I have found that the simplest thing is to fit a hub gear for a bike that is going to be used for bog bashing.

    There are options though.

    I would still prefer to be riding a SS, one less cable, and less to go wrong, so at the moment I'm trying to make a dinglespeed.

    Basically 2 sets of SS ratios, no gear change mechanism (other than a latex glove ), and when a different ratio is needed, drop the wheel and manually switch them over.

    I will have a 32/22 ratio, and a 22/32 ratio which means no chain length differences. The 22/32 is for crawler stuff and won't see much use mileage wise, but when there's bog, I'll love it. For those new to the concept, you only use the cogs directly in line with each other, you don't be run from the 32 front to the 32 rear for example - that would need a different chain length. It may sound like a lot of hassle, but it preserves the simplicity and reliability of a single speed transmission. I'll post mine up when it's done - I'm first trying to bodge a way to use a proper 32 tooth chainring on the rear rather than the flimsy derailleur types.

    Something like a SRAM Torpedo hub would be an ideal way to do this so the lower ratio could be optionally be ridden fixed for greater control (not possible at the moment because no brake mounts and narrow OLD).

    The ultimate is probably a tringlespeed, ie 3 on the front, 3 on the rear 38/32/22 going to 16/22/32.
    As little bike as possible, as silent as possible.
    Latitude: 57º36' Highlands, Scotland

  90. #90
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    Thanks for the info.
    richardh

  91. #91
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    Here's another newb Q:

    What is the max tire pressure for the BFL?

    Has anyone been trying to get a real high average speed on the Moonlander (or other fat bike) on flat tarmac/terrain? Is an average speed of say 17/18 mph (28km/u) possible on a 19 mile (30 km) flat Tarmac loop for a trained cyclist (medium performer not hotshot)
    Am wondering what is possible with this machine

    Thanks,

    Erik.

  92. #92
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    I'd think no problem for you Erik. I managed ~27kph cruise before pedestrian obstacles for a short 5km trip home from beach yesterday on my first test ride of my Fat Sand Bike yesterday. Successful ride along the beach with low pressure, still like uphill work if no choice, the erroneous rear Presta valve meant I could only get back to max 40psi in front tyre of the 4" Kenda from local fuel station. Lots of hand./foot pumping to go from near flat for the sand, to a couple hundred pumps later 10psi in the rear.

    re: Gearing, it has a Nexus8 hub, great all round, has

  93. #93
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    Quote Originally Posted by deepfraught View Post
    I'd think no problem for you Erik. I managed ~27kph cruise before pedestrian obstacles for a short 5km trip home from beach yesterday on my first test ride of my Fat Sand Bike yesterday. Successful ride along the beach with low pressure, still like uphill work if no choice, the erroneous rear Presta valve meant I could only get back to max 40psi in front tyre of the 4" Kenda from local fuel station. Lots of hand./foot pumping to go from near flat for the sand, to a couple hundred pumps later 10psi in the rear.

    re: Gearing, it has a Nexus8 hub, great all round, has
    Thanks!!

    Anyone know if Big Fat Larry's are also capable of handling 40psi? Guess inflating the tires to this amount of pressure by hand is a workout all of it's own

    Others who are willing to share experiences with maximum and/or average speeds on their fat bikes on flat tarmac or paved roads??

  94. #94
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    I read some research on weight and tri/track cycle times to be very low percentage differences when hills and braking/accelerations were a minimum. <4% I recall... but point is it's not major.
    So if you can sustain 35kph+ on that flat tarmac 30km circuit with your lightest road race bike, take off 10% and you're still above the 28kph target average. You'll be in the ball park in any case. On a ride the greater time isn't the 1 or 2kph avg. speed difference from conditions or fitness, but all the ordinary logistical things you do either side of it. Good or bad routine can make more difference.

    About pressure, I found anything above 20psi seems to have a similar contact patch and not change radically until it's halved once and twice again. Chronic masturbation disorder would do well as training for in field inflating a fat bike to be able to avoid passing out from fatigue before reaching the climax road tyre pressure =D
    I'll be looking for a full size floor pump with folding handle/feet. The MTB single foot and handle folder has been large for road/MTB so far, pumping against ground, with hose, but just not enough volume in fat bike world. Takes about 200 pumps on the full size to get from near flat for sand to 40psi. 0-20psi the most, and 20-40psi not as much it seems.

  95. #95
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    Craft, I pump larry's up to 3 bar for road only trips, is on a 47 mm rim, until 2 bar you notice a big difference in rolling resistance, between 2 and 3 bar the difference is rather small.
    30 km/h on flat works but you take much more wind and accelerating costs more energy!
    Me hartrate is 10 beats higher whithout to much wind!

  96. #96
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    Quote Originally Posted by Nothing's impossible View Post
    Craft, I pump larry's up to 3 bar for road only trips, is on a 47 mm rim, until 2 bar you notice a big difference in rolling resistance, between 2 and 3 bar the difference is rather small.
    30 km/h on flat works but you take much more wind and accelerating costs more energy!
    Me hartrate is 10 beats higher whithout to much wind!
    Thanks Much

    Since I can't pm you (post count is not enough here's my reply in Dutch

    Hallo N I,

    Bedankt voor je reply op het MTBR forum!!

    Lijkt me best leuk om op een Fatbike straks met 3 bar in de banden te kijken hoe het gaat met (gemiddelde) snelheid.

    Gisteren is de fatbike besteld en nu 4 wkn wachten....het wordt een Surly Moonlander.

    Ik heb sinds ik geïnteresseerd ben geraakt in een fatbike al enkele filmpjes van je gezien op Youtube en moet zeggen Respect met hoofdletter R. Prachtig hoe je met jouw Sandman de wielersport bedrijft! Een mooie inspiratie voor de hartpatiënt die ik ben ;-)

    Bedankt!

    Erik.

  97. #97
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    Bedankt, trouwens, ik spreek over een larry op een 47 mm velg, een big fat larry op een 80 mm heeft mogelijk helemaal geen 3 bar nodig!

  98. #98
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    Best Fat Bike Wheels For Heavy Riders...?

    Hello Everyone! My name is Ock and I am a very heavy rider. I am 5'11", and 290lbs . In the past I rode dual suspension Cannondales before the heavy weight. My last bike was a Kona Hoss which was made for heavy riders. When I spotted FatBikes online I loved them instantly. i am having one custom made for me. Hope you can help me choose the right wheels and tires for my weight and application.
    First, I really want wheels that are silver / stainless steel color / chrome look. Any recommendations for this?
    Second, I love the drilled look but the concern is my weight. Would undrilled be better for my weight?
    Third, which wheels would work best for a heavy rider. I am looking at Daryls and LArge Marge.
    Lastly, tires. The bike will be used on rocky dirt trails. Lots of sharp rocks and sharp vegetation. Im thinking Nate because of tread, and use goo. Origin8 Devastator is a choice due to its kevlar and its beefier.
    SO GUYS let me know what you think... The best wheels and tires for my specs and application.
    If you have any commments on componants for heavy riders on a fat bike please share.
    Thanks So Much! I will share whats created!
    OCK

  99. #99
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    Quote Originally Posted by Ock View Post
    Hello Everyone! My name is Ock and I am a very heavy rider. I am 5'11", and 290lbs . In the past I rode dual suspension Cannondales before the heavy weight. My last bike was a Kona Hoss which was made for heavy riders. When I spotted FatBikes online I loved them instantly. i am having one custom made for me. Hope you can help me choose the right wheels and tires for my weight and application.
    First, I really want wheels that are silver / stainless steel color / chrome look. Any recommendations for this?
    Second, I love the drilled look but the concern is my weight. Would undrilled be better for my weight?
    Third, which wheels would work best for a heavy rider. I am looking at Daryls and LArge Marge.
    Lastly, tires. The bike will be used on rocky dirt trails. Lots of sharp rocks and sharp vegetation. Im thinking Nate because of tread, and use goo. Origin8 Devastator is a choice due to its kevlar and its beefier.
    SO GUYS let me know what you think... The best wheels and tires for my specs and application.
    If you have any commments on componants for heavy riders on a fat bike please share.
    Thanks So Much! I will share whats created!
    OCK

    Hi Ock and Welcome

    I'm 265lbs so not too far south of you.

    If you are going to use the bike for rocky dirt trails I would recommend UNDRILLED Large Marges. They are totally bombproof.

    If you want the silver look, just have the black anodizing stripped before you have the wheels built.

    I have no experience of the Devist8er, but Nate is a very impressive tyre in both volume and grip

    Cheers,
    Dr FG
    A Fatback'd Lefty for who life IS a Beach

  100. #100
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    Left Turn

    Folks,

    I built a Jabberwockey with a fat front and I noticed that it likes to turn left. If I take my hands off of the bars... it will just roll to the left..

    No clue.. I have been around bikes forever, but this is the first Fat anything... is this normal for the Larry?

    Steve
    (I will post image later)
    My bike is heavier than yours - it does not have Carbon or Titanium parts - I love it!

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