The fat bike’s (slightly) slimmer brother
In the beginning, there was a pretty big gap in fat bikes and traditional MTB’s in terms of speed-oriented performance on dirt. While the big tires did offer up added traction and a smoother ride, they were still slow rolling and slow handling.
Since fat bikes were originally designed to be ridden on soft surfaces (snow, mud, sand, etc.), they didn’t need advanced suspension. Thus, they had a tough time handling the impacts of traditional dirt trail riding.
Then came the “plus-size bike”.
Traditional MTB tires average around 2.2” in width and are mounted on a fairly narrow rim. Fat bike tires run about 4” in width and are mounted on very wide rims. Plus-size tires average around are around 3” in width.
By splitting the difference between fat bike and traditional tire widths, plus-size bike manufacturers get the best of both worlds. They’re able to borrow the added traction and damping capabilities of the fat bike, but with less of the rolling resistance and slow handling characteristics.
Plus-size bikes are designed to be ridden primarily on dirt, so their suspensions and frame geometries are more appropriate for traditional trail riding. The bikes ride much faster than fat bikes, with more traction and a smoother ride than traditional bikes.
So what should I get?
If you plan to ride on snow, mud, and soft surfaces, you’ll want a traditional fat bike.
On dirt? Many people in the bike world feel the industry has finally nailed it with the plus-sized wheel and tires combined with modern bike design. They claim that plus size bikes will soon replace the traditional MTB altogether.
The smoother ride and added traction of the plus-size bike are selling points for many riders. In certain circumstances, these bikes offer the best combination of speed and control. Plus-size bikes definitely don’t fall short in terms of frame and component quality, as many of the bikes are spec’ed exactly the same as their slimmer tired cousins.
But we still don’t see fat or plus-sized bikes on top of the podium in dirt trail races. And that’s a big indicator that they’re simply not the best bet when it comes to terms of raw speed. Experienced trail shredders, downhillers, or dirt jumpers haven’t yet ditched their already very capable whips for plus-sized bikes.
Bottom line: On dirt, you probably won’t win your local race series or bang out KOM’s on Strava with your plus-sized or fat bike. But that isn’t always the point. The unique riding experience these bikes offer have proven that they have a place in the MTB world, and obviously, for many riders, they are the perfect tool for the job of having fun!