I’ve long been curious about fat bikes. When you first see a machine fitted with four or five-inch-wide rubber—you will just want to ride it.
I was told that these balloon tire beasts have evolved since then and now perform well across the board—they’re no longer just for sand and snow riding. You certainly see them popping up in a wide range of situations. I know of people using them as their go-to trail bike and others who race gravity enduro on them. In the meantime we’ve also seen a whole new breed of mountain bike appear—plus bike. Plus tires split the difference between fully fat and your regular MTB widths.
Fat bikes are generally accepted as having tire widths from 3.8 inches and up, although 4.0 to 4.8 is the most common. A plus bike has tires that are bigger than traditional tires and smaller than fat bike tires. These tires are found most commonly on 27.5 rims; however, Plus tires also exist in both 29-inch and 26-inch formats. The representative width is typically a 3.0 (as compared to 1.6 to 2.6 for ‘standard’ MTB tires), but they can range in size from 2.6 inches to 3.2 inches.
So the question comes: which one is more versatile?
Plus Bikes: When it comes to sand or snow riding, plus tires don’t offer a dramatic improvement over a regular MTB. Plus bikes are really for trail riding; the combination of super short chain stays and modern trail geometry delivers a confident and super fun ride that doesn’t differ hugely from a regular MTB, it’s just they provide a noticeable boost in cornering and climbing traction.
With the ability to run regular 29-inch wheels, they also offer great versatility and can transform into an XC/marathon ride for longer distances on less rugged trails. You’ll find a growing number of mid-travel dual suspension plus bikes too. They typically share similar no-compromise trail geometry and really stand to elevate the fun factor on rougher trails (sure, there are fully suspended fat bikes too but they tend to be short on travel with more compromised geometry).
From a trail riding perspective, the only real glitch comes with the desire to keep the tire weight in check. Yes, lighter tires make the plus bike feel great but it can also make them more puncture prone, especially when ridden hard over rocky terrain—something that plus bikes love to do.
Fat bikes: These beasts are in a whole different league for both traction and flotation and will take you places that other bikes simply can’t. You can use them on the trail too, but the bike setup becomes critical if you want it to be an enjoyable experience. Fit slightly narrower and faster rolling rubber (around 4.0 is a good compromise), set it up tubeless and there’s no reason why you can’t take to the trails on a fat bike. Compared to the plus bike, it won’t be as agile in consecutive turns or as comfortable when airborne.
It’s also worth noting that some novice riders will really benefit from riding a fat bike. The big tires don’t get stuck on smaller obstacles like diagonal tree roots, so they can really help to provide confidence for riders who struggle with getting the wheels off the ground (plus bikes offer this too but it’s not as pronounced).
Fat bikes really excel where there is no track. That’s what they were originally designed for and it remains their strength. However modern fat-specific standards have allowed bike designers to normalize their handling somewhat. Pick the right tires and you can happily take your fat bike to the trails. It’ll never be quite as agile as a plus bike when it comes to slicing and dicing single track at speed but that won’t bother some. As with the plus bikes, tire selection for rocky trails will always be a balancing act between minimizing the weight.
As with plus bikes, an extra wheel set can further expand the versatility. Some fat bike owners choose to build a spare 27.5 plus or 29-inch wheels for regular trail riding. Both of these alternate sizes share a similar outer diameter to a 26 x 4.4 fat bike wheel; it’s a good option if you want have one bike to do it all. Between the tire choice, air pressures and options for alternate wheel sets, the fat bike offers huge versatility.