Can a fat bike be your only mountain bike?

8 02 2013

Dropping in on the Green Machine…

Update: I’m reposting this from a year ago because I keep reading the same question from folks online. I figured it was worth putting out there again. Interestingly the 2012 new product cycle has come and gone without a reasonable cost production fat suspension fork being announced. That means for now most fat bikes will remain rigid unless you want to order a fork from Europe [ie. Sandman] or get something modified to work. So that’s really the question you need to ask yourself – Can a rigid bike be my only mountain bike?

If you are taking the time to read this post you probably already know that fat bikes are not just for snow or sand anymore. People are starting to ride fat bikes on trails that they could ride with a standard 2.1″-2.4″ mountain bike tire. Two questions I get asked frequently are 1) can a fat bike be my only mountain bike? and 2) why ride a fat bike on a trail that a normal MTB can ride?

Can a fat bike be your only MTB?

The short answer is yes.

The longer answer is yes, but you need to be realistic about what a fat bike can do well and what it’s not ideal for.

First off most fat bikes are rigid. Yes there are some niche suspension options, but nothing that I would say is reasonably priced, widely available and high performance. That will change in the next year or two, but for now you are most likely going to be riding a fully rigid fat bike. That’s good in that it will be low maintenance for harsh environments. Fat tires do provide some very limited suspension action all on their own when properly inflated. A rigid bike can be fast and efficient on smooth trails. However, as the trail gets rougher and rougher you have to slow down to maintain control plus you’ll have to stand a bunch to absorb impacts. The end result is a slower more tiring ride on rough terrain.

Secondly most fat bikes are heavy with slow rolling rubber. In order to keep costs low in a niche part of the bike industry companies are specing their bikes with heavy cheap parts and basic frame tubes. Given that wheels, tires and tubes on a fat bike are bigger than a normal MTB to begin with using heavy parts here exacerbates the problem. If you have the know how and $$$ you can put your fat bike on diet the same as any bike. Although if you are going to spend $4K on a light fat bike you might want to consider spending $2K on a stock fat bike and $2K on a light stock 29er hardtail to get more bang for your buck. Riding a heavy bike is tiring if your trails involve a lot of climbing and constant accelerations. OTOH smooth rolling trails don’t penalize a heavy bike as much.

Thirdly what do your buddies ride? The bike you ride will dictate the trails you prefer, the speed you ride and the distance you ride. If your friends are on rigid 29er single speed rigs a fat bike would likely fit into the mix a lot better than if they had uber light XC bikes or 6″+ travel all mountain bikes.

Fourthly how steep and techy are the trails you ride? Production fat bikes have pretty middle of the road MTB geometries that are good for XC riding and plowing through snow. They don’t have the super slack angles of an all mountain rig. As the downhills get steeper and rougher you won’t be smiling nearly as much as you could on a fully suspended MTB with really slack angles. The steering geometries of fat bikes are starting to vary a bit more from somewhat slacker snow friendly options like the Salsa Mukluk, to all rounders like the Surly Pugsley and dirt specific designs like the new On One dirt specific fat bike. So it’s worth doing your research before you buy.

How fit and skilled a rider are you? The better the engine and skill set the less of a handicap a heavy rigid bike is. In fact if you are the strongest rider in your posse a fat bike might be just the challenge you need to stay even with your friends. OTOH if you struggle to keep up with your regular riding partners as is do you want to make each ride more challenging?

Do you ride alone or will you be riding with other fat bikers? As soon as you take other bikers or other types of bikes out of the equation the unique capabilities of a fat bike really shine. As an exploration rig and a fun machine the big soft tires on your fat bike will let you go places and ride in ways you never thought about before.

So ultimately the answer is that a fat bike is a mountain bike and there is no reason you can’t ride it on your local dirt trails. Rigid is fun, simple and easy to maintain. Just don’t loose sight of the downsides.

Fatties – not just for snow!

Why ride a fat bike on dirt trails?

It’s not unreasonable to ask why bother riding a fat bike on dirt trails when the big rubber isn’t needed for flotation. Here are my top 10 reasons…

  1. you already have a fat bike and don’t want to buy a 2nd rig.
  2. you want an excuse to buy a fat bike, but don’t have snow or sand locally.
  3. you’ve ridden your local trails so many times on normal MTBs you are looking for a fresh perspective on the same dirt.
  4. rigid fat bikes provide an efficient semi-suspended ride that’s very fun.
  5. you want to explore your local area more and need fat tire floatation/traction at some points of your rides to do so.
  6. your local trails are only rideable year round with fat rubber.
  7. you are so strong and generally awesome that you need a handicap for rides with your friends/SO to be fun.
  8. your regular full suspension MTB is a maintenance hog if ridden in wet sloppy conditions so you want a rain/mud bike.
  9. you have no idea what’s going on, but you can’t stop thinking about riding a fatty.
  10. all the cool kids are doing it….=-)

The green zone…

29er Fatty MTB

Note that you can convert almost all fat bikes to standard 29er MTBs with a second wheelset and possibly a suspension fork. The 170mm symmetrical rear dropout fat bike frames work best for this conversion. Once completed you’ll have a 29er with a ton of tire clearance! This might be a good option if you want to use all your stock fat bike parts and spend your upgrade $$ on a light 29er wheelset. Setting up a fat bike as a rigid 29er is no problem. If you want to add a 29er suspension fork you’ll have to consider the stock fork length vs. the suspension fork length and determine whether the fat bike’s handling will be negatively affected. Keep in mind once you roll on 29er MTB hoops it’s really not a fatty any more!

Photo: It’s Time to Ride Blog

The Future

As fat bikes continue to gain market share and folks ride them more on dirt you’ll see lighter stock bikes being sold by the major players as well as dirt specific designs which will include hardtails as well as fully suspended fat bikes. Once we have light suspended fat bikes readily available the answer to these questions will change. If you can’t wait and have a lot of $$$ to spend you can get a custom built fully suspended fat bike from a number of bike builders.

Scott rocks my Pugsley…

My Reality

I ride my Surly Pugsley on our local trails as a straight up mountain bike. Not because I need to or I have any aspirations for a 1 bike fleet. It’s a great all around bike that puts a smile on my face when I throw a leg over it. With no suspension and an IGH it’s very low maintenance which is ideal for our sloppy winter conditions and the traction of huge 4″ knobbies isn’t a bad thing either when our trails are wet. I do get beat up a lot more on the Pugsley than on my 29er hardtail or 26er full suspension bike so I ride less aggressively and I don’t use it every ride. I’ve been keeping tabs on the current state of the art in fat suspension forks. I may well buy one at some point, but so far the cost/performance/availability curves haven’t hit a sweet spot for me. I understand some of the major players have fat forks in the works so I’m hopeful there will be something I’m stoked about out for the 2013 or 2014 riding season.

I don’t see myself getting rid of the Pugsley until the frame dies of natural causes. It’s a very versatile fat bike for XC riding, snow/sand missions and bikepacking. Once fat suspension hits the mainstream I could probably be talked into a new fat bike designed to work with a suspension fork…possibly even a full suspension rig. The Pugsley has a short stock fork on it which doesn’t lend itself to adding suspension without compromising the steering geometry. If I do get a hardtail or full squish fatty the Pugsley will get refocused as a soft conditions machine. A mission it tackles well.

Update: I’ve decided to give up on the Pugsely as a MTB. My Nomad does a better job and between full suspension and huge 2.4″ tires gets enough traction to ride our trails in winter. The maintenance issue is the only drawback, but riding a fully rigid MTB on our rocky/rooty trails wasn’t as much fun as I had hoped. I’m going to keep it for soft conditions use and for bikepacking.


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30 responses

24 03 2012
Dylan

Good post, Vik. But, as you know, I’m kinda biased about this subject.

24 03 2012
Dan Sloan

i agree on all points
I might add, don’t get pulled in by the hype and the hipster look. People are always saying how they can ride a fat bike through 8″ of fresh snow, etc., Not true. if the snow is packed down a bit , its good but nothing will get you pedaling through more than 3 or 4 ” of virgin snow. Also I would reiterate, they are heavy and all the new light, wide rims are single wall and drilled so for technical xc type riding they probably wont stand up. Lastly , adding suspension will also add weight and take away from pedaling efficiency

24 03 2012
DerrickP

Great perspectives. I battled with this decision last year when I was shopping for a new MTV. I went with the Troll because the Pugsley didn’t seem practical enough. It fell into the maybe-one-day-as-a-fun-bike category but didn’t meet my requirements for regular use.

Thanks for all the insight.

24 03 2012
Vik

@Dan – quite a few large guys have been hammering the light weight single wall fat rims on dirt/rocks for a season and so far the reports are good. I haven’t heard of any failures. Given my weight [175lbs]and riding style [conservative] I don’t think I would have any issues.

24 03 2012
Dan Sloan

hard to fathom since even regular rims are double wall and not drilled. I guess time will tell

24 03 2012
thelazyrando

Having 4″ wide tires with 4 times the air volume of a 26″ MTB tire as a cushion between you and the ground probably helps dissipate a lot of the forces the rim would otherwise see.

28 03 2012
Rob E. Loomis

Excuses 2 and 9 for me. I’ve never had much interest in mountain biking just to mountain bike, but there are times that the most direct route to my destination has terrain I wouldn’t take my regular bike over. Well, maybe I would, and have, but slowly and fully aware that the bike is not cut out for what I’m doing. I am really drawn in by the idea of a bike where pavement, or even roads in general, wouldn’t be the limiting factor in where I could go. This may be the year I have to break down and find the money for a fat bike. I’m only at the beach one week a year, and snow rarely happens here, but I’ve been dreaming up other places where some fat tires might come in handy.

28 03 2012
Doug@MnBicycleCommuter

Very well written post Vik. You covered a lot of different points. I especially like the Top Ten list. #1 fits me the most. I don’t ride trails except in the winter with my Pugsley. I keep thinking I may take it out in the summer.

29 03 2012
bicyclenomad

Vik

Nice to sum things up – also good to have an excuse not to get rid of the dual suss quite yet!

Getting a Pugs in the next few months for go anywhere tourer with bikepacking kit, and for Western Australia pea-gravel which is completely unrideable in summer on anything less than 3 inches.

Tom

30 03 2012
Joe Keenan

Yo Vik,

About to return to the states and debating reg 29er or fat bike for the Bend Oregon terrain.

Very helpful post as usual from you

slo joe recumbo

31 03 2012
thelazyrando

Welcome back Joe. Good luck in your search and let me know what you end up getting.

31 03 2012
Joe Keenan

Thanks Vic

Early look’n seems like it might be a Mukluk because it has a 15″ frame and I’m short, but walk tall.

Have a hard tail 29er (Motobecane) over here in South Africa where the mtb riding is awesome. Only want one mtb and for Bend winters the fat bike will prolly be my choice.

On an off note, really looking to get a rando series done in Oregon this summer.

31 03 2012
thelazyrando

@Joe – just to give some options the 907 comes in a small & XS frame size. The Fatback goes down to a 14″ frame. Both offer very low stand over for their frame sizes as is.

16 10 2012
brian

Nice write up. Some responses I am not so sure of their experience. I have been riding a Mukluk 2 for over a year now and can’t believe the terrain that is now open to me. Do I prefer a fast mtb hardtail ride on hard packed mtb designed trail, hell ya! But that just is not the norm for a local ride for me. I need to get over long sections of sand to ride the fun stuff and in the winter well… FTB is here it has its niche for the right environment. Everything depends on what your typical riding environment. What kind of riding will you do or what to do. The FTB allows multiple options if you have a one bike stable.

8 02 2013
s.wolfe

glad to see this re-posted.

i just finished a fall of riding nothing but fat bikes here in bend. i was able to go from hot, dry days in august to fall aspen leaves changing and high country drying out, to first turns on dry snow, to current melt/thaw/refreeze nights and i have been doing all of it on one bike. i even had about a 10 day period where the necromancer was my commuter both out of weather necessity and to get creative on the ride home. there is a lot about riding this bike that reminds me of my first 29’er. rigid karate monkey, 3-4 tire choices, etc. my personal experiences aside, i think we’ll see more variety available with fat bikes over the next couple of years. the more adventure oriented folks and all day epic riders will probably see the enjoyment in going fat year round. the weight weenies probably won’t.

i don’t think suspension will make these bikes better. i think tweaking geometry will elevate the performance of these bikes much more than adding a little squish will.

8 02 2013
Greg Weber (@onespeedgreg)

The one thing that has kept me off of fats as a primarty ride… Q factor, (Tread) I get on them and just cant see pedaling that for any length of time. Its the one thing that stands out, and feels weird about all of them. I know that a 100mm bb and spindle that goes with it should not make that much difference, but for me it does. Just feels gross.

8 02 2013
Rivers

Hey Vic, I just posted this on our Google+ community…great post!

10 02 2013
beingmalcolm

How about this: If I had to own only one bike it would be a fat bike. ’nuff said.

11 02 2013
Joe

Well said. I could only afford one bike. Sold my 29er and bought a Fat Bike. Winter here in Central Oregon and have been on snow covered MUP and forrest roads. Look’n forward to spring and exploring more of the forrest.

Slo Joe

3 06 2013
Dave (DieselFuelOnly)

Hey Vic great summary and it answered the questions i had for now. I’m still riding the pugs as my all rounder and only miss my FS 26 when I’m chasing my buddies downhill. Have you written a comparo tween the Pugs and the Krampus? I’m curious about how you’re finding the Krampie

4 06 2013
thelazyrando

@Dave – I have posted info on MTBR.com in the Krampus threads:

http://forums.mtbr.com/29er-bikes/surly-krampus-802452.html [there are a couple more in the Fat Bike & Surly Forums]

The Krampus is a MTB with big tires and not a fat bike. So it’s not going to work in soft conditions nearly as well, but it’s faster, more nimble and more playful to ride.

4 06 2013
Dan

I have a modified lefty on my Pug, you probably wont be getting any fork that will be lighter. that said, I’ve got holy rolling Darrells, light tires etc. and its still 35lbs. you could shave off 1/2 a lb. with aluminum frame or a lb. with Ti, . My point , I don’t see a fs version being very practical, the chain line is an issue as well as weight, and honestly, its probably not even needed. The fork is great over rough stuff and potholed snow in winter but the tires and a thudbuster takes up any rear issues. Its a fun bike, I also use it for trail work to haul out tools. but for most people I don’t see it as being their only bike.

24 10 2013
7 11 2013
nlm

I am looking at a 9zero7 with the 170mm rear to be setup with a normal 29er wheelset and tires for commuter duty in the non-winter seasons. My LBS though has reservations about spoke tension/strength going from the wider hub to the narrower rims. For this setup they think that the a 135mm rear would be much better and they are right, it definately would be better. The question though is whether a 170mm rear would be really that deterimental for a rear 29 wheel?

7 11 2013
Vik

@NLM – they are wrong. A 135mm wheel will have 17.5mm offset to the driveside to deal with. For a “normal” 29er wheelset that’s a challenge. If you can find a rear 29er rim that has some spoke offset that will help build a strong wheel.

With the 170mm hub you can build up a strong 29r wheel with symmetrically drilled spoke holes since there is no wheel offset to deal with.

Your LBS has the concern backwards.

21 11 2013
nlm

@Vik, I think the concern was not so much the offset but that a 170mm hub *might* be too wide for good spoke tension leading to a 19-21″ wide rim. Yuo have no concerns about this though?

But I see what you mean about the offset on a 135mm frame. I thought the 9zero7 135mm sliding dropout was lateral/perpendicular to the frame so that it would deal with offset issues when needed. But their slider just lengthens or shortens the stays as needed correct?

21 11 2013
Vik

@NLM – I don’t see how a wide hub affects the spoke tension. The extra width just makes the base of the “triangle” wider which is a stronger setup. The problem with spoke tension is when the opposite sides are unbalanced – ie. a wheel with poor side to side symmetry will have one high tension set of spokes and one lower tension set of spokes.

You can try mocking up various wheel builds on a wheel building program and see what each option does to the spoke tension and bracing angle.

170mm rear 29er wheel

Let’s put it this way this is the first time I have ever hear anyone concerned about building a 29er wheelset with a 170mm rear hub.

The 907 offset frame is offset 17.5mm to the driveside. This never changes. The slidig dropouts move back and forth to take up chain tension for a SS/FG or IGH drivetrain.

21 11 2013
nlm

@Vik thanks for your thoughts. Thats good to know b/c I really liked the option of going to a wider tire in the rear of the 170mm frame if I wanted too.

15 03 2014
surface604

Reblogged this on Surface 604 WordPress Blog.

2 05 2014
Benji

I’ve been commuting spring summer and fall, for may years. This past winter was my first for commuting. My coldest morning here in northern WI was -34 deg. F. In November I purchased my first Fatbike. It is a fully anodized, flat black, 190 Fatback, handmade in Portland Oregon by Zen frame shop. It weighs in at 29 lbs all wet. Today is May 2nd, and I have yet to take it out due to poor environmental conditions. I will be taking it out within the next three days, weather permiting. I haven’t been able to get myself to take my Picaso out in the nasty elements. You would have to see it to truly appreciate its beauty. In January I purchased a Salsa Mukluk 2, second hand. The salsa weighs in at 37 lbs. Both frames are aluminum. I have commuted on the Salsa, 9 miles one way, almost every day since. Fatbikes have become the only bikes I care to ride. I’ve even purchased a Burly Nomad so I can take them grocery shopping. Fatbikes can be your your only bike, if you so choose :-)

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