In the beginning it was simple, but simple isn’t always great.
When FatBikes broke into the ‘mainstream’ (sorta) a decade or so ago arguably the biggest component difference to the bikes was their tires. After all, that’s how the bikes got their “Fat” moniker. That difference meant however that there wasn’t much to choose from. Manufactures were rightly hesitant to jump on the bandwagon when no one really knew how far it was going to take them, so there were only a handful of tires to equip your FatBike with, and there wasn’t much to distinguish the choices that there were. They were all about 4 inches wide, made of similar compounds, with similar tread patterns meant for slow slogs in difficult terrain.
Well, things have changed considerably in a relatively short time frame. Today we have plenty of options from a number of manufactures. Most FatBike tires are between 4 and 5 inches wide (with corresponding rim widths, which is to say not all FatBike rims can fit all FatBike tires, or at least not well – more on that in a bit), and until very recently virtually all FatBike tires had been 26″ in diameter but we’re now seeing the emergence of 27.5″ diameter Fat tires as well.
Preference in width is fairly straight forward. Narrower is more efficient and behaves more similar to a traditional mountain bike tire while wider offers the most traction and float. So, if you’re using your FatBike primarily on groomed trails, on urban terrain that includes some on and off road, or if you’re doing local winter non-enduro races (like the ones that the fine folks at 2WHEELREVOLUTION.CAput on), 4 inches is likely all you need. You’ll probably be faster and more nimble.
If you’re taking your Fatbike to the back country, a local frozen river after a fresh snowfall, or Manitoba’s premier ultra endurance winter bike event, Actif Epica (registration opened today btw), you might want the most float you can get with 5 inch tires.
Of course width isn’t the only thing that affects a tire’s race characteristics. These days there are many tread patterns to choose from as well, ranging from virtually slick (well, for a FatBike tire anyway) to huge, aggressive knobs. Many local riders and racers opt for tread with moderate knobs and moderate spacing, similar to what many of us use on our conventional mountain bikes, but more aggressive tread words well if you often find yourself in deep snow, sand, or even in the summer outback.
Many, though certainly not all, treads come either studded or studless, and some come studdable so you can customize your stud pattern with a separate stud kit. There are many opinions on studded vs. studless and on custom patterns, and we’re not sure there’s a hard and fast rule on what’s best in every situation. A lot if it comes down to personal preference and riding style. Conditions can vary so much from day to day on the same stretch of road or trail that to be honest there often isn’t a perfect solution. But, there are a lot of ‘good’ solutions.
Rubber compounds, sidewall materials and construction, etc also make a difference to ride characteristics and weight. Most notably a higher TPI (thread count) makes sidewalls more supply and responsive. Some manufacturers now offer the same tire model in more than one TPI; the lower count is cheaper, the higher count feels a little better, and is usually lighter too.
Before we wrap up this brief FatBike tire overview we should also mention rim width and frame clearance. Every FatBike frame should be able to accommodate at least 4 inch wide tires but some are not made to fit 5 inches. That can be because of inadequate frame tube clearance and/or drivetrain clearance. Obviously that means you need to think about whether or not you want the option of riding 5 inch tires before you buy the bike. Also, not all Fat rims work with all Fat tires. Generally speaking narrower rims (say, approx 55mm-80mm) work best with 4 inch tires while wider rims work better with 5 inches. That’s not to say you can’t often force wider tire / narrower rim combos, or vice versa, but depending on the combo it might result in too much or too little tire sidewall bulge that in turn adversely affects handling.
Oh, and just to complicate things we have the aforementioned recent advent of 27.5 inch wheel diameter FatBikes. To this point we’ve been talking about the much more common (at the moment anyway) 26 inch diameter set up. Much of what we’ve discussed here applies to 27.5 inch tires and wheels too but it’s worth noting that there’s another standard out now. Some bikes can easily accommodate 26 inch or 27.5 inch (for instance, Salsa’s Beargrease started out as a 26 inch wheeled bike before it was offered as a 27.5 inch set up last year using exactly the same frame. This year the frame has been modified to be more 27.5 inch specific though).
Just as during the inception of the original FatBike platform the main drawback to 27.5 inch Fatties right now is lack of much tire choice, but it’s very likely we’ll see that change as (if?) 27.5’s become more prominent.
It’s hard to go wrong no matter the FatBike setup you choose but ultimately the best way to make a decision is to come down to the shop and check some bikes out in person. We’re here and ready to help!
P.S. Did we forget to talk about tubeless? Not really, because everything else we’ve said applies whether you choose to use a tubed or tubeless set up, but for the record there are a number of tubeless FatBike tire/rim combos on the market today. Just one more choice to make!