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.