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Prototype Talk: Full-Suspension Fatbike

Last Friday afternoon a shipment of prototypes arrived and a bunch of us hurried down to the PD&D shop in anxious anticipation.

We'd like to show you our prototype Full-Suspension Fatbike frames.



The inspiration for this project came from numerous people within our team (in a strangely timely convergence actually) and from the fact that fatbikes are being ridden all year long as opposed to being strictly thought of as snow or winter bikes. There is such tremendous capability within these machines that we wanted to have some full-suspension prototypes built to explore the concept further.

Pete did what Pete does, and took the plans with him on his last trip to Taiwan. Now the frames are here and we can't get our pulses to drop.



We know there will be questions about these frames so we're heading off a couple of them right from the start.

1) We have assembled and are cobbling together a small selection of suspension forks that will allow us to build, ride, and test these prototype frames. We hope that a fat-friendly suspension fork will be available someday.

2) These are prototypes. We expect to learn a lot from them. They may or may not eventually become an actual product. That is undecided at this time.

We are quite confident that this probably has some of you fatbike riders pretty fired up, so we'll start by throwing a couple hypothetical questions out at you:

1) How much front and rear travel would you prefer in a full-suspension fatbike?

2) What tire and rim width would you prefer?

What's next? Well...we've got a bunch of wheels to build and a handful of bikes to assemble. And then...we ride. Stay tuned for some ride reports in the coming months.

This post filed under topics: Fatbike Prototype Tim Krueger

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ABOUT THE AUTHOR

Tim Krueger

I come from the land of trees, lakes and cheese. I like beef jerky, singletrack and pale ale. I believe derailleurs were invented for a very good reason. Long rides with good friends and campfires is really what its all about. Oh, and if its not anodized, its worthless.

COMMENTS (136)

Guitar Ted | January 10th, 2012

Whoa! Mind blown…..


I would say as far as suspension goes, its main duty should be damping first, travel second. Those fat tires already have a fair amount of un-damped give. Three inches of travel on a fat bike would be far plusher than three on a 29"er if you use your air pressure correctly. If you just pump up the tires to rock hardness, what’s the point? Ya know?

The rims should be on the order of 50-60mm and double walled for durability.

Dean Frieders | January 10th, 2012

Clearance for Rolling Darryl’s and Big Fat Larry’s. 80mm rear travel, 80-100 up front. Full front lockout. Abbreviated gear options (2x7 or 2x8) instead of ridiculous chainstay bends (a la Moonlander).

At the very least, clearance for 4” tires (Husker Du), but by that point, BFLs on an 82mm rim are easy.

Devian Gilbert | January 10th, 2012

I had one of the first pugsley and recently sold it after about 5 years.  I loved that bike, and rode it A LOT!  The Mukkluk and MoonLander have caught my attention, but now a FS Fat bike?!  I’m very interested.  Especially if it took 100mm wide rims.

Liam Gannon | January 10th, 2012

I’m curious to see what fork you guys will use, that thing looks incredible!

Wade Liedtke | January 10th, 2012

Personally I’d go for a 3.7 tire. As far as travel, I’d think no more than 4 to 5 inches front and rear since the tires give so well. I can’t WAIT to see one down at INTERBIKE (hint hint!). What an incredible idea!

Josh Patterson | January 10th, 2012

It’s great to see you guys pushing the envelope. As for suspension forks, a Maverick SC32 or the Flame fork perhaps?

Elvis. | January 10th, 2012

travel - 3-4” (you’ve plenty in the tyres to start with)
rim width - will probably run 65mm myself, but would be nice to *able* to run 82mm
tyre width - 3.7-3.8” range. (no need to go as far a Big Fat Larry)
fork - right here - http://www.german-a.de/en/flame.html

oh and this just saved me getting a local framebuilder to modify a 29er frame.

Thanks guys.
You read my mind!
(they’ll be a ti version right?)

Mike C | January 10th, 2012

Maybe 3 inches would be useful in the rear, but I’m not sure in what situation.  Between the large tire and suspension pedaling efficiency might turn the ride arduous, turning this into a point and shoot 40 pound downhill bike?

A belt drive, alfine, 100mm rim, tubeless Big Fat Larry rear under 30 pounds is the design I’m praying for.  Switch from suspension fork in summer to non suspension in winter…

Bob Costello | January 10th, 2012

1) Given that the fat tires (with suitably low pressures) are kinda like having 1” of suspension alone (not really, but sorta :), I can’t see needing more than 3”/80mm of travel being “necessary”, especially given the dearth of viable fork options.

2) BFL’s on hundies are pretty much the standard now. Any frame that can’t get there somehow will be deemed unfit.

Adam | January 10th, 2012

I think that this is a true case where bigger won’t necessarily be better.  Finding the right combination of floatation, weight, and efficiency may not be as easy as just adding a rear shock.  Its great to see Salsa displaying such a progressive attitude.

DG | January 10th, 2012

I’ve been riding and racing my Pugsley in 29’er mode with a Maverick DUC 29er fork for the last season, and I’ve been pretty happy with that.
I’ve seen Large Marges under the Maverick forks and I’m having a wheel laced up now with the intentions of running the Husker Du(when ever I can get ahold of a set..), though I’m not real sure what advantages are really to gain from it other than appeasing the nerd within.

I’d say just spread the stays on the Horsethief. Two birds with one stone:FS fatty and more traction for the gnar….?

Yosi | January 10th, 2012

Is it a modified Salsa Horsethief ?

cmherron | January 10th, 2012

I agree with Mike C.  I’m trying to figure out what situation a FS fatbike would be best suited for.  It’s a super cool idea and I LOVE that you guys went there.  My initial response was that this thing would be a super inefficient beast that would be more effort to pedal around than it is worth.  The big tires already give a good chunk of “suspension” and I think if they are run at the right psi, they even feel better than some 3-4” XC bikes.  If you can develop some type of rear suspension design that will negate any pedalling inefficiencies then you might have something.
Either way, I dig your style!

Adam | January 10th, 2012

I think I would prefer more of the old Dos Niner set-up.  Another 1.5” would be nice to help keep from bottoming out on rims.

Pat W | January 10th, 2012

1.  Ingenious.  2.  Pandora’s box. 
29er, suspension is already limited for travel, so there is answer one.  100mm rim capable should be the standard aimed for, but you are the first so stand strong; you might be the only ones to go this direction.  Who is going to build the hub to handle the possible torque with the fat combo?  Mike C should have some good opinions/knowledge on that.

cvo | January 10th, 2012

couple of us in Lincoln have been chatting about this,  seems like 80mm is a good start for a front fork,  and maybe about the same for the rear.  looking forward to reading some reviews and maybe, just maybe riding one in the future.  Fell in love with my Pugs this year, looking forward to going even bigger next season.

Brendan | January 10th, 2012

You’ll need at least 200mm for when the crevasse opens up and swallows you whole!

Dan | January 10th, 2012

Interesting.  I’ll be eager to learn more about the suspension systems that go on the prototype.  I wonder if any accommodations will have to be used to handle subzero temps and their impacts of increasing the viscosity of suspension oils. As a nordic skier I am used to waxing for the conditions, will we have to modify our suspension systems too?

Chris | January 10th, 2012

i think 1-2” on the rear and maybe 2-3 MAX on the front would be close to optimal. i’m guessing you’ve done some modeling to determine how the geometry changes? also need to ensure that racks and luggage won’t get in the way.

re: fork… maybe you should start making your own crowns in order to fit a 3rd party’s stanchions/legs?

Darren | January 10th, 2012

What about using any existing DH fork and machining up new crowns?

Donnie Collins | January 10th, 2012

I have been riding for the past 2 years on my fat bike. I personally would be interested in buying a 3-4” version if it was available. We have a group of 11 here in Muskoka and it is growing fast. We have been in a couple publications and are being interviewed by a TV station this coming Saturday. I used to look at these things and scoff under my breath. Now my $6000 6” travel loaded rig sits while I ride the big bike year round.

Cheers from Muskoka, to you and all you do!

Ward Whitmire | January 10th, 2012

WOW! Love it!  I’ve been riding year round for 3 years now on a custom XC FB built specifically around the Maverick SC32.  It has 90mm travel w/ the 29er kit I believe. W/ Larrys (or Nates) Ft. & Rr., it rocks & rolls in all terrains. Never going to be as light as a reg. MTB, but it’s adjustability (tire pressure wise) lets me dial it in for so many different terrains. And the way it rolls over stuff! I’m convinced the Ft. susp. has allot to do with my bikes “all ‘round” ability’s. It can’t hold a candle to my 100mm rimmed snow/sand specific bike in dunes or snow, but it is my 1st choice now (over all my bikes) for riding everything but sand and snow… “The One That Get’s Used”!  Hopefully, now, Maverick will bring back the SC 32 and/or someone else w/ throw they’re hat in the fat susp. fork ring.  Oh ya, I’m sure your on top of it, but don’t forget to raise the BB up a bit. Low BB’s are fine on rigid FB’s but nothings worse than too low of BB on an FS… smackin’ peddles all over the place.

Good luck with this project!  Would be glad to take it for it’s dune test….

-WW

Jack | January 10th, 2012

Got dam*! I would buy this no mather what! I would use it for high grass (africa savanna style) trails, forest, downhill, race no snow/sand!
Why no snow/sand? Well we alredy have the Pug, Muk, 9:7 etc.. A full sus would be fun for “offroad” race or downhill.

1. Fork: Maverick SC32 or Flame since they are alredy out there right now for fatbikes.
2. Larry for offroad race and Nate for downhill. Large marge 65mm for downhill (standard no cut-out) since they can take a beating. Large Marge cut-out for race.

OldnPhat | January 10th, 2012

Narrow rims, lower profile 3.7’s w/higher pressure, 3-5 inches travel… what a fun beast.

KC | January 10th, 2012

This is one great prototype. Looking forward to see this in production in the near future. Suspension fork? What about this cool custom one off Rock Shox.
http://i147.photobucket.com/albums/r317/kveninga/2011fatbikeforkcrownjpg.jpg
http://i147.photobucket.com/albums/r317/kveninga/2011fatbikesuspforkjpg.jpg

Elvis | January 10th, 2012

this thing would rule in the Simpson Desert Bike Challenge. http://desertchallenge.org/

Fat tyres for sand, suspension for the bum & hand killing corrugations.

BRING IT ON!

John M | January 10th, 2012

1) 80mm suspension front and rear would be perfect, 100mm front and rear would be fine but more than necessary from my perspective.

2) Rolling Darryls with 3.7/3.8 tires would be my ideal.The ability to fit larger tires would be a nice but unnecessary extra.

I currently ride a Gary Fisher SuperCaliber full-squish 29er, and a MuklukII. I have enjoyed the Fisher immensely, but absolutely love the MuklukII as much in non-snow seasons as winter.
I do find myself missing a moderate amount of suspension front and back on The Mukluk. It would be great to be able to run the tires with a few more psi and have some real suspension with consistent rebound damping ( and susp lockout for the minority of situations when needed).

This prototype full-squish fatbike is a pretty exciting development.

If you make it available, I will buy it in a heartbeat.

Please bring it to market ASAP.

Andy | January 10th, 2012

I would go for 4” travel front and rear.  Regarding forks, Maverick claims they are going to redesign the SC32, and German Answer has been making the Flame forks in a wide version for Sandman, but as of now both are pretty hard to come by.  It would be cool to talk to White Bros about doing a custom fat suspension fork.

Alan | January 10th, 2012

Oh yes! Need.

Eric | January 10th, 2012

80mm’s of front travel, and 5.5x1.0 in the rear. Maybe 4” to 5” tires, (not sure what that’d be exactly). This is Awesome!! I’d definitly buy one if you made it a production model!

Elvis | January 10th, 2012

@ Andy - funny that you (and others on MTBR) should mention White Brothers. I contacted them about 6 months ago asking the very same question…

their answer? numbers baby… get them numbers to make it worthwhile and they will do it.

Russ Higster | January 10th, 2012

A variation of the Pro flex elastomer system of yesteryears would be my perfect spec.

Wade | January 10th, 2012

Fat bikes keep getting fatter.  100mm rims with BFL’s are the way to go - for float over loose.  I personally would love a Big Fat Nate.

Suspension travel in the 4” range would be enough for me.  I found a 4” 29er was equivalent to a 6” 26er - and these big tires are 29er height, plus having a bit of cush themselves.

So - for my desert riding mix of sand wash and rocky chunk asks for the fattest rim/tire and 4” travel.

PS: Just converted a Lefty for front duty with a pair of 1 1/8” special long clamps (similar to P321).  Travel limited to 95mm, works great.

Sam | January 10th, 2012

My question is what suspension would do to load capacity and pannier/rack options?

Dylan | January 10th, 2012

What Mike C. said, to the letter!

MG | January 10th, 2012

You know my address… I’m on-board! That’s not a snow bike. That’s a 100% of the time fun bike! Heck, send me one and I’ll race it at the Dakota Five-O… No joke.

Dang it… Too bad I gave up my SC32. Oh yeah, you guys know where it’s at.

Jerry | January 10th, 2012

Marge Lites with Nates or Larrys and 80mm travel. And keep it under, or around, 30 lbs. please.

Mike Burden | January 10th, 2012

4” front and rear works well on a full sus fatty as I know from experience .

http://forums.mtbr.com/fat-bikes/fattening-up-pony-quest-fat-rs-begins-664573.html

You would need to have enough clearance and MUD room for a minimum of a Nate on a 65mm rim (96mm wide on this rim).

But…. tyres and rims are getting FATTER :)

Best to build in some ‘room for maneuver’ , say 120mm rear clearance.

Dr FG :D

Muz | January 10th, 2012

Great to see you guys marching on with development. Personally I think it would not require too much travel perhaps 40-60mm rear and 60-80mm front. My reasoning being that I’m not sure what it would do to your cadence/rhythm pedaling over extended rough conditions. I’m racing in the Simpson Desert Bike Challenge (see Elvis’s above link) and I’d really like to know how the FS performs across a mixure of soft to hard to arse shattering terrain in one 80klm stage.
Also I would like to see testing done on all terrain with the tyres set up with a ghetto conversion. I usually run as low as 4-5psi in the rear and use Graceful fat sheba’s (82mm) and I would like to know if the suspension travel will help to negate or increase tyre burp. The burping can be an issue with the GFS as they don’t have the locking bead (or what ever it’s called) like an UMA II has.

Muz | January 10th, 2012

Great to see you guys marching on with development. Personally I think it would not require too much travel perhaps 40-60mm rear and 60-80mm front.

My reasoning being that I’m not sure what it would do to your cadence/rhythm pedaling over extended rough conditions. I’m racing in the Simpson Desert Bike Challenge (see Elvis’s above link) and I’d really like to know how the FS performs across a mixure of soft to hard to arse shattering terrain in one 80klm stage.

Also I would like to see testing done on all terrain with the tyres set up with a ghetto conversion. I usually run as low as 4-5psi in the rear and use Graceful fat sheba’s (82mm) and I would like to know if the suspension travel will help to negate or increase tyre burp. The burping can be an issue with the GFS as they don’t have the locking bead (or what ever it’s called) like an UMA II has.

Edweird | January 10th, 2012

Risse Racing makes triple clamps for the Marzocchi 888 and Fox 40. I can’t imagine it being terribly difficult (or expensive) to design and manufacture wide triple clamps, wide axle and disk brake rotor spacer for a set of DH forks. If you build one with 8” rear travel and a conversion kit for 888’s I’ll buy one. This would be a killer ‘freeride’ bike in the purist sense of the word.

Joe | January 10th, 2012

Love you guys going there.  THIS is why I’m a fan and I buy your bikes. Regarding forks, I suppose they are a competitors (but sometimes, business makes strange bedfellows) but I’ve seen Cannondale Lefty front suspensions on fatbikes. 

When I think about what I love about my FS and what I love about my fatbike, the 2 things don’t really overlap.  FS is about breakneck speed (especially downhill), very plush landings, and a certain degree of safety/control when hitting something hard.  My fatty is about perma traction and ability to traverse anything. So how do you mate those two? 

The fatbike tires offer cush, but I call it bounce.  There’s no rebound and compression control for a fatbike tire.  Going fast and hitting jumps/landings can be precarious.  Introducing control to that is a good thing.  I don’t think you need much more than an inch or two of travel in back.  Much more and I think the bob of suspension plus bounce of the fatty tires would be too much.  On front I think you could go 3”.  I’m thinking a fatty Dos Niner I guess. 

Since the reason to go full suspension is more for spring/summer/fall, I don’t think you need to go WIDE and heavy on the rims.  This could keep weight down and give you more than enough traction for 3 seasons and enough in the 4th.  With 3.7” wide surface, bald endomorphs offer a ton of traction on the dirt.  Husker Du’s look like standard summer xc/singletrack tires.  I think Large Marge XC would be fine here unless you have something else in the works that is strong enough for the summer, but lighter.

So yeah, driving principles for me would be not too much travel, keep the weight down for the sake of speed and being nimble, and the fatness of the tires will take care of the go-anywhere ability.

GMB | January 10th, 2012

Do it, it will sell.

Rod Budnik | January 10th, 2012

I love so much of what you guys do.  I should - I own a Mamasita, Big Mama, and a Mukluk 2, however, this just seems silly.  Maybe if you add an outrigger to it.  :)

Ah-ram | January 10th, 2012

so gnar bro!

ATBScott | January 10th, 2012

I think that 4 inches would be about prime for a bike like this…  Any more might be overkill - but the capabilities that a big tire can give you in some rougher situations might be finding that you are hitting some drops and trail features that will be more than 80mm could handle.  Older DH fork as the basis for a dual-crown 100mm fork?  Maybe see if Fox or RS can make you some longer stanchions for a 100mm dual crown?  Find an old Maverick fork?  Be able to run 100mm rims and BFL tires and I think that would suffice.  For the FS bike I’d probably go 50 - 65mm with 3.7’s anyway…  Awesome project!

Jim C | January 10th, 2012

I think I just wet myself.

Ward Whitmire | January 10th, 2012

@Wade ... I’d like to see a Big Fat Endo for dunes.

KP | January 10th, 2012

I`am sure there will be a market for it,but not me sorry.I was so happy two years ago when I got my 1st fatbike,very simple EZ to maintain just get the psi dialed in an your good to go (anywhere & any season)and not having to rebuild forks & suspensions & still have a nice riding go anywhere bike.Besides I have my new Lynskey 29er for that suspension riding stuff,good luck with anyway.I do love my Mukluk just the way it is,Fargo is next on my list(Ti?)

John | January 10th, 2012

I think a minimal travel bike would be the ticket.  I don’t think you’ll need 5 inches of travel depending on what you ride.

Jeff | January 10th, 2012

No longer saving for an engagement ring.

PK | January 10th, 2012

Jeff - You made me spit beer out my nose, awesome!

Sevo | January 10th, 2012

Man I love the peanut gallery answers.

First off, 100mm rims the standard? Hardly. I see them being great for dedicated snow/sand use (if you ride enough of such), but I want narrower, lighter rims as do I believe anyone who really rides a fat bike year round has conveyed to me. So I say 82mm rim max and make sure it fits the Husker Du….but that’s it. Big issue will be making sure the frame bits don’t start twisting….and keep the weight down. Big tires and big rims I see only leading to big problems or big scale numbers.

As far as rear suspension goes….80mm. Heck maybe even just 65mm. My worry would be how much more bounce you’ll get from the tires at speed. So, be sure to test the bikes with 15 psi…see how that goes. Is it a high pressure for a fat bike tire? Sure But it’ll give you an idea of how the bike will react with such.

Maverick fork would be great….if we knew there would even be a Maverick at all by the end of this year. I don’t see that happening. German A flame fork is cool…but I think $900 retail? Not feasible. White Brothers I think is the ticket….but got it right when they said it’s all numbers.

May sound silly but….try a Softride stem up front. 60-80mm travel rear. I road a similar setup on an Aermet/AMP rig back in ‘97 in the Midwest.Worked better than expected. I ran a 2.5” Specialized up front for a tire too.

I happen to have a Softride stem…and some other bits. Be happy to test one out. :)

ti | January 10th, 2012

the raw finished color its beautiful

John | January 11th, 2012

I like it. This is a great way to make your fat bike easier to use all year round. I think 80mm-100mm would be enough front and back. As far as the tires, bigger isn’t always better but I think having the option is a game changer. Nothing worse than finding the perfect tire for you then finding out it won’t fit your frame. I have heard of folks using a Maveric fork like the DUC 32 on their fat bikes. Maybe look into something like the Truss fork used by Jeff Jones, that’s a sick looking fork. Good luck with the project, I really like where you are heading.

slappy | January 11th, 2012

Wicked! there were a couple of things i launched off in moab last year having too much fun on the pugz and the 33” ti bar from blacksheep was the only thing that saved me, acting as my suspension. My buddy has a Maverick with rolling darylls and the Nate 3.8’s rub under load. That flame fork from answer germany looks nice on the sandman but may not be wide enough. I’d like to think a single crown fork would be enough, i’d want and even 4.8 of travel for the 4.8 tyre cuz if you;re going full sus on a fatty you best be gettin real rad. anyhow Nate 4.8’s are the future and the stompariLLAZ would undoubtedly love gettin rAD on that thing.  ps anyone seen that picture floatin around the web of the custom fatty with a turner like rear suspension set up and a rohloff and a maverick fork,  pretty cool lookin wherever it is   oh yeah it would also be nice to have a box section center dished rim with 90 plus mm of width but a lil more structure for launching that thing, imagine the lines in fruita dropping down horsethief whoa nate 4.8 rear nate 5.4 up front?

Alex | January 11th, 2012

I think that 6” of the front and rear travel - will be good!

Captain Ridiculous | January 11th, 2012

This…is awesome.  To preface this, I’m the type of guy who rides a 140mm 29er for everything including XC trails and races because more travel is fun.  As much as I’d love to see a 140mm FS fatbike, it’s not going to be worth squat until there is an appropriate fork for the front end.  The best options now are ~80 and ~120mm, so as much as I hate to say it, going with 80mm to start would probably make the most sense for what this would end up getting used for. 

What exactly would it get used for you ask?  If it were me (which it will be if this comes to fruition) it would basically never see snow, it would be used on singletrack year-round in NC, races, SWANK 65, etc, which means the other geometry cues would probably be more important than travel (like as short a CS length as possible, ~69.5deg HA or slacker).  This would be used for all the stuff my WFO sees now, so I vote for making it more geared towards dirt since that’s where the benefit of the suspension shines at speed, much more so than in snow.

Beyond that, I’m only going to put the nobbiest tires around on it (when it does inevitably make production…), being the Nates.  That being said, you can rest assured if all this work was put into making something as crazy and aggressive as this, it would get reamed by the fatbike community if it didn’t make clearance for BFLs on 100s, so that’s a must. 

Overall, this is a very, very promising start.  Call me when test platforms are ready, I will pay for one.

David Gardner | January 11th, 2012

I don’t have a fatbike, but I have a soft spot in my heart for all things Salsa.  We are getting a good core group of riders in Indiana who sport the fatbike, and I’m sure will welcome your new development!  Personally, I like the idea of using 36mm stanchions on a proprietary crown/steerer with not more than 100mm travel, and 80mm max on rear.  I like the idea of switching out to a rigid fork AND a strut (or elastomer) to replace the rear shock for winter and/or extreme cold weather.  Tire wise, it has to handle the biggest ones made.  Tires are such a personal preference, both on the perfomance and aesthetics.  I’ll be watching your progress, good luck!

Vik | January 11th, 2012

I think 100mm travel front and back is all you’d ever need with room for 3.7” tires on 82mm rims.

Trying to fit 4.7” rubber on 100mm rims will require a bunch of extra design compromises and isn’t that useful for the dirt/trail fatbike rider.

The big issue is you need a front fork that doesn’t suck. I don’t think their is a fatbike compatible front fork on the market that is really solid.

Great idea and I’ll happily be a customer if this concept hits production with a nice fork on the front.

safe riding,

Vik
http://www.thelazyrando.com

Vik | January 11th, 2012

I think 100mm travel front and back is all you’d ever need with room for 3.7” tires on 82mm rims.

Trying to fit 4.7” rubber on 100mm rims will require a bunch of extra design compromises and isn’t that useful for the dirt/trail fatbike rider.

The big issue is you need a front fork that doesn’t suck. I don’t think their is a fatbike compatible front fork on the market that is really solid.

Great idea and I’ll happily be a customer if this concept hits production with a nice fork on the front.

safe riding,

Vik

BrentF | January 11th, 2012

I would still rather see the El Mariachi or Fargo Tandem, I feel it fits in better with your Adventure By Bike theme.

Dave | January 11th, 2012

Mukluk-grade tire clearance (or better) for future tires and mud.  3-4” rear and geo which will work with a 4 or 5” fork, should folks want to slacken it up.  While this will be a fun daily cruiser, its home will be superchunk (5 Miles of Hell, UT) and I hope the geo reflects as much.

Well done Salsa.

Sean | January 11th, 2012

I’d think the 3 - 4” travel would be about right with fat tires.  Make the rear dropouts bolt on to allow for 170mm centred, 135mm offset or 135mm centred (IGH) hubs.  Spacing for 80mm rear rims seems sufficient for most applications.

As for forks, I think it would be useful to be able to fit 100mm rims.  135mm spaced hub. 

I’d run a bike like that with BFL/100mm up front, Nate/80mm in the back.

anvil_den | January 11th, 2012

I have been discussing something like this with some pals for awhile.
Basing on say the 5” Flame fork—with fat tires height, it could set up a lot like many of the ~6” bikes in the market. But of course with the added advantage of the big rubbers.

6” rear would be nice but would need a suspension design that can really pedal up well, otherwise this will be an Archille’s heel. However given the space constraint, I would say 4.5-5” travel would be more than sufficient.

I guess amount of travel preference would vary depending on what kind of rides one is intending for such a rig. Mine is geared towards something that could be used like a mini DH and taking some 4-6’ drops with ease. Wouldnt mind a little more squishy on normal trailing days.

coflo | January 11th, 2012

This is rad!

100mm travel front and rear would be ideal. Thru-axles for better tracking with such a large contact patch. 80mm rims and 3.7 Larry/Endo/Nates would be perfect. If this works out I can see the potential need for stronger rims or using the OG Large Marge DH rims.

Tom N | January 11th, 2012

I’d like a 142mm rear hub and at least a 15mm front

80 to 100mm of front & rear travel. 

80mm rims. 

Mounts for a fender on the front (bosses on the under side of the down tube) and rear. 

Bosses for a dropper seat post.

A chain suck plate or bosses to mount your own plate for whatever cranks you decide to use.

Tom N | January 11th, 2012

I’d like a 142mm rear hub and at least a 15mm front

80 to 100mm of front & rear travel. 

80mm rims. 

Mounts for a fender on the front (bosses on the under side of the down tube) and rear. 

Bosses for a dropper seat post.

Bosses to mount a chain Suck plate.  Make your own plate for the cranks you decide to use.

Christopher | January 11th, 2012

Very exciting development! Can’t wait to see any updates.
Speaking of prototypes…I would be interested in taking Rustflake or Snowflake off your hands, so you have more room for the new prototypes of course…

Jeffk | January 11th, 2012

I would think a ideal bike would be 80mm travel F&R although 100mm would probably be ok. I see it almost as important to control rebound than absorb bumps. 65mm Marge lite rims that you can run tubeless and 3.8 tires. I would actually love a 3.2” tire in a tread similar to Husker Du’s, tubeless and even 50mm rims.  Keep bike under 30 lbs would be awesome. But I am never going to be on snow so I do not need the super wide float.

Chris Sanders | January 11th, 2012

I will buy a full suspension mukluk right now, please build it.  Here is Tucson Arizona I can find you at least 5 buyers.  I love my mukluk, it’s all I ride in the southwest anymore.  Please build it.

Chris

MY | January 11th, 2012

I would like this bike if it shared goals with the horsethief.  To that end, I think if it cleared large marge rims with a 3.7-3.8” tire, that would be sufficient.  I would point it downhill as much as possible.  I can’t imagine how well it will corner.  If I owned one, it wouldn’t see much snow use.  Maybe a slackish headtube?  I am sure you guys will get it dialed.

Stroganof | January 11th, 2012

80mm rear will be fine, rigid up front is fine as well in the snow.  I rode a modified Turner XCE Fatbike for 4 years before going with a ti Fatback (a friend fabricated a cro moly rear end).  It has some issues (high bottom bracket, nut-cracker top tube) but it was VERY smooth over the nasty stuff.  When the trails have frozen hoof/foot prints and are just plain nasty, the rear suspension lets you power through it in comfort and stay seated.  The rigid front was never an issue, but the rear was a huge bene.  If you can keep the geo the same as a good fatbike the FS would be great.  The Turner was also a big plump - riding a light snow bike is more fun than riding a porker . . .

IMO the “suspension” offered by the fat tires is over stated and over rated.  Sure, it works for small stuff, but when the tracks are nasty they are frozen, and when they are frozen most of us ride higher with PSI in the tires at which point the “suspension” effect is negligible.

cs | January 11th, 2012

Do it right from the start, 100mm front and rear travel.  If you build 80mm the following year you will be doing 100mm.  80mm/100mm rims and 3.8 tires/ 4.7.  However, if you can from the start build 100mm front and rear travel, 100mm rims and 4.7 BFL’s no one can complain.  This is a year around bike.  (snow riders will keep a mukluk hard tail on hand if the ride sub 40 temps).  The weight will be 35-37 pounds and that is just fine.  I saw some people ask for 30 lbs or less, many 100mm travel 29ers in the $2800 range are 33 lbs so don’t worry about the weight at 35-37pounds.  I love this idea.

Michael | January 11th, 2012

Put this beast into production! Beast sounds like a good name for it too, or The Honey Badger!

Dan | January 11th, 2012

Tim,

You guys really know how to stir the pot don’t you?  100mm sounds like overkill, so 100mm’s it is.  “TOO MUCH” is “JUST ENOUGH”.  You can dial in the suspension as needed or downsize/upsize the tire/rim combo.  I’m not even much of a FS fan, but this caught my attention!

Cool stuff.

Derek | January 12th, 2012

I’m surprised that people are struggling to find a use for this bike! This would be a great bike for when it gets really nasty on technical terrain. Snow or mud laying over an already technical trail could be easily slayed by the extra flotation and traction this beast could offer. Also, it would be a great bike for beginners to try on very technical terrain. Also, I would definitely try to jump this thing in the snow in a bigger way. Maybe including a little visit to a snowboarding terrain park!

As far as your fit questions go, I would love to see it be able to fit the normal 3.7-4” tires on a Rolling Darryl. I think putting Big Fat Larry’s on it would be too much overkill.

A | January 12th, 2012

Make it a tandem and you will be undisputed king of the bike world in my eyes.

Vito | January 12th, 2012

100mm way too much! I really don’t think you need that much. Personally I feel that anything over a 80mm-82mm is overkill. That being said, I think Large Marge Lights or something to that affect would be awesome on this bike. I wouldn’t want to go bigger because of the weight factor, but what the hell do I know. The fun factor is really cool, but I just don’t get the need for suspension on a true fatbike. Those tires provide plenty of cushion.

Dan | January 12th, 2012

With so many 80mm travel forks out there, I think that’d be a good zone for rear travel too. There’s so much cushion in the big tires, I see no real need for more. I’d love to see something like your Dos Nine for the rear. Small, simple, light & pivotless. As for rims/tires… I can see this bike being a great double duty steed. Fattys for the soft stuff, and swap in some 29er rims & rubber for fast hard trail use. Consequently, I think being able to fit 3.8s on 82mm rims is as far as you need to go. Even with suspension, I wonder if the single wall rims will survive. What I’d REALLY like to see would be your alternator dropouts though. That way it can be built as a clean looking SS or IGH. Maybe with only one chaining/cog it could swallow even bigger rims/rubber. Cheers!

Charlie The bikemonger | January 12th, 2012

That will be great… and certainly another demo bike in the shop.

ATBScott | January 12th, 2012

The comment by Tom N re: a 142mm rear axle just made my brain click - the current Muk design has a 170mm rear end - are you guys doing a custom rear hub/axle for a 170mm thru-axle?  If not, you should!  (I’m having a hard time thinking that Pete hasn’t at least thought of this, as beer through the nose is quite mind-expanding…)  Also, an increased spoke count in the hubs/rims might be a good idea on this machine as it is just begging for some folks to see “how far” and “how high” it might go!  (“Bounder” as a name?)

Look Out Below | January 12th, 2012

There was a suspension for Fat tires made at one time Meverek made them. Oh and there is actually three full Suspension Phatty’s custom built already here’s mine. ;) I have to say it’s rides like a dream.

http://forums.mtbr.com/fat-bikes/another-full-suspension-phatty-757352.html

Snakebite | January 12th, 2012

These need 7 to 8 inches of travel.  Fully downhill racing compatible.  Four inch tire width compatible.  Hammerschmidt tabs.  Rohloff friendly.

Brad | January 12th, 2012

I got a chance to ride a fat bike a few months ago.  I was surprised how enjoyable it was.  I was left thinking I would like to get one, but I like suspension, so I put that thought on the back burner hoping someone would produce one someday.

I’d like to see this thing come into production!

swtchbckr | January 12th, 2012

Given the absolute lack of suspension forks for fatbikes, might i suggest you design and build a girder type suspension fork for these, using a single rear shock mounted in the middle, akin to the girder forks found on older motorcycles, or like the 90’s AMP Research Mtb forks.

wade | January 12th, 2012

The comments on axles got me thinking - I’m running 170/135 now, and started with nice lightweight QR skewers.  They were not sufficient to keep the wheels in place for trail/rock riding.  I have a shimano QR on the front, which has been working ok, and bolt-on the rear.

Thru axle hubs would be a very good thing! I think a 170 QR has too much stretch!

Ken Campbell | January 12th, 2012

I think it’s great that you are making a full suspension fat bike. I couldn’t wait so I built one for myself, the 100 mm suspension in the rear seems to be plenty. I couldn’t be more pleased in how it rides.

Ken Campbell | January 12th, 2012

I think it’s great that you are making a full suspension fat bike. I couldn’t wait so I built one for myself, the 100 mm suspension in the rear seems to be plenty. I couldn’t be more pleased in how it rides.http://forums.mtbr.com/fat-bikes/big-fat-gary-fisher-build-750739.html#post8625502

Stuart D. Wright | January 14th, 2012

First off, I really dig the idea and the prototype frame you have.

If people planned on using the bike sometimes as a snow bike it would be hard to carry much gear plus the reliability issues of the shocks/forks in extreme cold.  On the other hand it would kick ass in desert sand, loam and mud and snow mixed singletrack and light all-mountain riding.  Like a full-suspension cross-country bike on steroids!

Up front, it would be nice to have an inverted triple clamp style fork using the 135mm front hub.  Nice to have a hub produced this wide with a 15mm or 20mm thru axle while your at it.  Too much flex if spaced this wide for QR and disc brake. 

1.) 80mm of suspension in rear, 100mm up front would work for me.

2.) With the available rims already on the market, the 65mm LM would be the widest to have a strong build for serious bashing about.  Tires that are no more then 3.7-3.8 inches wide would be great too.

My two cents.

Dave | January 15th, 2012

I’m agree with Elvis & Vic here.

Travel - 3-4? (you?ve plenty in the tyres to start with)

Rim Width - I would run 65mm myself, but would be nice to *able* to run 82mm

Tyre Width - 3.7-3.8? range. (no need to go as far a Big Fat Larry)

A good suspension front fork with lockout.

I am a current Pugsley rider of several years now!

Keep up the good work, and innovations like this will keep you on top of the market. It works for Apple computers, right!

Pat | January 15th, 2012

When can I have one ???? Hurry Gota Have it

John Cripps | January 15th, 2012

AWESOME AWESOME AWESOME.  Yes this concept bike will sell if put into production.  I just joined the fat tire group in Muskoka Canada, noted above, and am in love with the sport.  I have never been on my team full suspension 21.5 pound mountain bike since throwing a leg over my 38 pound Pugsley.  Yes I am slower in many situations but what you can do with these bikes is amazing.  My only negative I experienced thus far on the Pugs was getting beaten up on rocky descents.  A full suspension front and rear with 80-100 mm of travel would be a dream.  Even 80 mm is likely adequate travel if you allow 80-100 mm rims.  It is interesting that Sandman front suspension bikes utilize a 47 mm wide TrialTech rims with 3.8 inch Larry tires and a German A flame front suspension fork.  I guess it takes some time and testing to sort these things out! Build it around 30 pounds and it will sell! heck even if it was 38 pounds I would still buy it!  Best of luck on this project.

Brian Williams | January 15th, 2012

WANTED: 4” travel fork for my Mukluk. I’m good with a thud-buster seat post to take the edge off. The german FLAME fork and the Rockshock on KC’s post look real good.

Sparthan | January 16th, 2012

That’s proto is simply amazing. You’re going to explore new frontiers about fat bikes. A doped Spearfish would be great.
I think 80mm would be the right compromise to do not have a taller bike or an higher standover.
Would be nice, talking about fat bikes, a fat version of Fargo. Would be the perfect bike for long distance and snow/sand riding in Alaska or Morocco. I would call it FaTgo.
Anyway, nice job guys, I’ll stay tuned.
Sparthan from Italy.

Tommy | January 16th, 2012

I agree with one of the commenters above. This would be a great concept for the glorious return of you DOS NINER setup. God would that be SWEET on a fatbike. That way you’re not worried about the reboundless suspension of the tires counteracting that fancy shock and 3” of squish won’t suck all the life out of it on the hills (I know it’s not a climber to begin with but come on, it could be worse). Just enough to give you that little extra squish, not add a ton of weight-performance-chainline issues.

Pat | January 16th, 2012

Ok been 6 days since you have started teasing us, whats the hold up, chop chop- bulid , bulid and bulid some more, that bike is slicker than whale spit, I think i am having a Fatty attack and need one soon

Scott | January 20th, 2012

Another name idea…?  Since you could send this thing: “Hukluk”

Jim | January 24th, 2012

Great Idea.  Put me on the purchase list.

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