It can certainly be your only bike.
Like most things there are certainly trade offs.

I believe the 29+ and 27.5+ bikes are primarily for trail use. I am unsure of their utility in anything other than completely packed snow.

(+)
Greater Versatility
Improved Traction
Confidence inspiring

(-)
Heavy
Slower rolling
Less common (trail side aid, tires, tubes etc)

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A fatbike can be your only mountain bike. I've taken my Salsa Beargrease out on dry singletrack and it is a lot of fun. However, if you ever plan on going on a ride with your buddies and you are the only one with a fatbike you might find yourself lagging behind. I'd add a used fatbike before the winter after getting a non-fat bike for the rest of the year.

I'm seeing a lot of them (10-20 a day) on local trails now where just a year ago I might have seen 1 or 2.

"I'm seeing a lot of them (10-20 a day) on Ebay now where just a year ago I might have seen 1 or 2."

For all-around mtb'ing, spend your $$$ on a nice 29er HT or 27.5 FS - don't buy a fat bike. You'll be much happier.

It can be depending on what fat bike you get and what kind of riding you'll be doing.

I have a Full Sus 29er and a fully rigid fat bike. I rode the heck out of the fat bike this past winter, both in snow and on the trails. Once the trails fully dried out its all 29er. It's lighter, faster and more comfortable.

I do occasionally ride the fat bike if I go for a ride with my kids or when we go camping. The flat pedals make it more convenient and I'm not worried about speed.

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Formerly DrD

I have a Specialized Epic I use for racing. I decided to get a Trek fat bike. It last 3-4 months with minimal riding. I sold it. I really had no over pressing desire to ride it over my 29er. If I didn't have a 29er then I would have kept it, since I need a mountain bike. So yes, it can be your only mountain bike. I will say fat bikes are surprisingly fast on rolling courses. On hilly courses they are a dog, which is fine if your not racing.

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The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design.

Seems like most people that complain about fat bikes are the ones that don't spend enough money on the fat bike. Because of the weight issue, it's much more important to spend a lot of money on a fat bike to really enjoy it.

My Farley 8 is actually 4 pounds lighter than my 26 Hardtail but it cost three times as much.

i have been doing a weekly race series on the same course for 8 weeks. The last race was pretty muddy so i figured i'd trash my fat bike. Overall it was OK, but i was slower and finished a few places down from where I usually am, I suspect the 37 pound weight on the climbs did not help, nor the bus-like handling. So, yes you could have plenty of fun on one, but I much prefer my 26" full suspension for our rooty singletrack here in the northeast.

I'm hoping the bike will be fun for riding on snowmobile trails this winter, that's why I bought it

i live in a community where quite a few people ride fat bikes during the winter (on snow). a few of the--very few--ride them during the summer.

what you say is true: one can build a light fat bike which will completely change the game, BUT...if your fatbike is lighter than your 26er HT you've got a dog of a HR. i have a 29er HT that is under 17 with di2. when you compare apples to apples, the fat bike is ALWAYS going to be slower vs a light 26er/27.5/29er HT/FS (take your pick!).

I use it both. Just deflate the tires a bit for single track. I might suggest full suspension for technical stuff.

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Human Person

Yes, my fattie is sporting some of the widest rubber out there on 90mm wide rims and weighs in at a hair over 27 pounds. My 29er fs bike with similar level components weighs 3 pounds less.
Where the fattie starts to shine is for fit riders with limited technique. There is no picking of the line or having to measure out effort, you just point and pedal.

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"When the going gets weird, the weird turn pro."
Hunter S. Thompson

So I had a full suspension mountain bike, and I recently purchased a Trek Farley 8, hard tail with 100MM front fork suspension.


I replaced my full sus with it, well in the sense that I haven't had a mountain bike for over 6 months, and my new purchase was going to be a mountain bike. I opted for the Farley.

So the cool thing about the farley is it FEELS just like a mountain bike in the sense of geometry. It's aggressive, capable of being quick and twitchy, you can even throw the back around if you're strong enough and have enough momentum. Also, if you just want to go around and literally crush trails and turn on auto pilot? this does it really well. Rocks? roots? Ruts in the ground? Hell, animals? Forget about it, it'll run it over and ask for more.

It's really cool as well to ride in the snow, or where I'm at, the desert washouts. Being able to cruise where mountain bikes with bigger tires would get bogged down is neat, and I explored a ton of new places that I didn't know existed before hand.


The bad? It really sucks in the mountains and technical terrain. Even with the suspension, the sheer width of the tires and how big they are create a balloon sort of suspension, which really screws up anything technical. The good thing with full suspensions is that they dampen the bumps but keep the rear wheel down, allowing you to keep grip/momentum/stability on corners where you would loose it with a hard tail or a full rigid.

What the balloon suspension does it just bounce you around, you have no real clue where the rear is gonna land, and being unfamiliar with it I ended up biting it hard and giving myself a nice puncture in my left hip flexor. Was off the bike for a week nursing a leg that had a huge wound in it, so life kinda sucked for bit.

I also thought that using it to race around in the desert would get me faster as well... You know, big fat heavy bike and hills.. Well the gearing on the bikes are pretty damn big, so it really didn't feel like it was much more of a workout...Unless you threw down some heavy gears then it was just impossible to ride it... You go slow enough as it is, so pedaling in a heavy gear just made you that much slower and not that much stronger.. I may be biased. I'm a podium level cat 2 mtb racer here in the southwest where the competition is pretty good, but I'm definitely not the most "skilled" so YMMV


That's my .02 cents with it. I think that having a rigid fat bike in a place where it gets a decent amount of snow and winter riding is common would be warranted.. Hell If I were to move to Canada or up north in Michigan/Minnesota where the snow was plentiful, there was a scene, I would actually get the newest Trek Farleys since they can hold a 5 inch tire. But if you really just want to use it for mountain biking/casual riding, save the cash and grab a full suspension or a hard tail. There's enough on mtbr.com or even ebay to get one for cheap.

a friend of mine usually does a lot of power based indoor training during our very snowy winter months, he's a cat 2 road rider and does well off it, but this year all he did was longer 3 hour fatbike rides in the woods. The result? At 41 he's having a great mtb season, winning races all over the place. So, maybe it will get us faster this winter after all.

He agrees with me that it's kind of a barge to ride in the summer

Couldn't agree more with the post above. They are just another tool on the swiss army knife of bikes. It'll never fully replace a mountain bike unless you don't have the need for the specialization of a mountain bike.. Or if you do, it's like that really, really dull knife that looks cool but you never really get any good benefit out of it.

I've noticed a similar response. I only did a handful of trainer rides this winter. I did get out on the fat bike 2-3x/wk though. At 45 I was 2:10 faster on my 20k split at my first race vs the last time I raced that race 7 years ago. Lugging that 35lb beast through the snow was not only a blast but was a similar workout to my trainer interval workouts.

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Formerly DrD

One more voice to say that:

YES) a fatbike is great training/fitness tool to keep you riding over the winter.

I got one this past winter and spend exponentially more time in the saddle because of the pure joy of biking (I never get that on the trainer), and I really noticed the increase in comfort & fitness come spring when I got my TT bike out.

I can't praise the fatbike enough for winter riding, and I rode her a bunch on the spring trails and roads through the shoulder season too.

And NO) if you ever plan to ride with friends. Fatbikes just roll differently. Sometime a little quicker (particularly the monster-truck effect over really technical areas), but mostly they're just slow, sluggish and heavy.


So: if you plan to mountain bike alone for fitness and solo fun: go for it. However, if your primary reason to get a mountain bike is to be social or go fast; not the right bike.

I have a dual suspension Trek Remedy and and older Rocky Mountain ETSX, this past winter I went through a few different fat bikes before finding what I wanted, a fully rigid 907 Whiteout. It weighs 22 pounds built up with HED wheels and Sram XX1 in a 1x11 setup. I rode that 5 times a week all through last winter and now find myself using it trail riding as well and it's my go to bike these days.

I think it really depends on what your trail conditions are like, who you ride with and what your goals are. Where I live we have a large fat bike community, the trail conditions are ideal for fat bikes since the majority of them are soft, boggy, wet, rooty, rocky and the fat bike just flies over all of it, the traction is amazing. I find I am usually dropping my riding partners on these trails when I am on the fattie and they are on their hardtails. Other trails though it's the opposite.

As a novice mtber now becoming better I have to say the fat bike is the best purchase I've ever made. I first had a specialized Rockhopper, then upgraded to the stumpjumper FSR, and now am on a Fatboy. The great thing about the fatboy and fatbikes in particular is that they take out a good degree of the need for technical skill on the trail. They simply roll over things and handle terrain better than thinner tires. There's less need to worry about choosing the right line because their so forgiving. My fatboy weighs about 28lbs and is certainly no slouch. I'm not looking to set records or anything but I'm much faster on my fatboy than I was on my stumpjumper and I live in the Adirondacks of NY where the trails are stupid rocky and rooty.

Thanks to everyone for all of the responses. I was hoping that one of the new 27+ or 29+ not-quite-fatbikes with front suspension might be a good compromise, allow me to do some winter riding in an area where we don't have a ton of snow, but not be too ridiculously sluggish for doing a fair amount of trail. There was also the idea that I could a much nicer bike vs splitting my potential budget between a mtb and a fatbike later.

However, I am in Colorado and I hope to be doing a fair amount of proper mountain biking that is not limited to rolling trails so it seems like I still would be limiting myself by going with something a lot heavier than most everyone else I'd potentially be riding with. I'll probably still end up getting a fatbike eventually for pure winter riding and for something to slow me down when riding with my SO over the summer but that can be a separate purchase later.

Now to start researching mountain bikes, few years ago I was sold on a carbon 29er HT, now with all of the developments in 27.5" FS I'm not too sure... but that's a separate debate.

I'd only limit yourself to one bike if financial or spouse/partner considerations intervene. S-1 and whatnot.

If you have any ambitions to race or keep up with people on regular MTBs, the "skinnier" tired MTB seems the smart choice.

I'm looking into a "fattie" MTB so I can do some of my rides with the kids (on their road bikes) and still get a decent workout. The only other reasonable application for one here in Tucson is to make rock gardens less technically demanding.

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Hard work beats talent when talent doesn't work hard.

FYI. I got a Motobecane Boris X7 from Bikes Direct for $700. It does everything I want from a winter/snow bike for a relatively low entry price. I did replace the stock tires with On One Floaters. World of difference with traction in moderate snow conditions.

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Formerly DrD

 
I met a guy at the trailhead a few months ago that was singing the praises of fat bikes. He had a full carbon rigid Fatboy with HED carbon wheels. It was quite a bit lighter than my aluminum HT 29'er. He said he went from a 29'er to this bike and won't go back. Said you can ride any line you want, climbs better due to better traction, and he is faster on the downhills as well. I haven't ridden a fat bike yet, but he was convinced they are the way to go. This was on foothill trails in the desert, not sure if he would make the same claims in forested single track or not.

If you have decided on a FS 27.5, I would recommend the Scott Genius or Scott Spark. Friend of mine rides the Genius 740, with the twin-loc system it climbs really well and he is an animal on the downhills. It weighs the same as my HT 29'er. He has a 1X setup that helps in the weight department, and I have a triple. So I could get my weight down below his, but his really isn't bad for a 6" travel FS bike.