Trek Pioneers All-New Tire Size with Release of New Farley Fat Bike Models: 27.5×4″

Trek released several new-and-improved versions of their Farley at Sea Otter this year. The key updates? Carbon frames and 5″ tires now available, and a brand-new 27.5×4″ tire size.

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Lower-end Farley model sporting the new 26×4.7″ tires.

5ish-inch (actually 4.7″) tires have been a long time coming to Trek, but the new Farley frames are totally compatible with the fully-fat tires. Trek has gone with a 197mm rear hub to accommodate the width, and they’ve added quality touches such as through axles front and back. However, despite a wider rear end, the q-factor remains unchanged.

Carbon frame, rigid carbon fork

The Farley is also now available in a variety of carbon models, with the option of a Bluto suspension fork or an all-new Bontrager rigid carbon fork. All of this carbon means crazy-light weights: the carbon fork weighs in at a stunning 600 grams with an aluminum steerer or 550 grams with a carbon steerer. Add that to the 1300-gram frame weight (size 17.5) and you’re looking at an absurdly-light fat bike frameset.

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Continuing with the carbon theme is a new Wampa carbon wheelset. The wheels feature a hookless bead and are setup tubeless right out of the box. According to Trek, all of this carbon goodness will provide high-end stock bike weights of about 23 pounds… for a fat bike! If you want, can definitely get the bike lighter if you really bling it out.

Bluto Farley option.
Bluto Farley option.

Trek has also rolled out a kids version of the Farley to keep up with the growing competition in that niche.


Brand New Wheel/Tire Size: 27.5×4″

Trek also released a brand-new wheel/tire size: 27.5×4″. Now take note: this isn’t 27.5+, but rather a 27.5″-diameter full-fledged fat bike tire. Previously, all fat bike tires were only available as 26″. If you can get past your frustration of yet another wheel/tire size, Trek claims:

The outer diameter of 27.5×4 and 26×5 wheel system (wheel + tire) are within a couple of millimeters of each other. A wider 26×5 wheel system offers the most capability in loose terrain. The 27.5×4 wheel system offers a faster solution great for groomed snow singletrack and dirt trails.

Getting way more rowdy on a fat bike than I ever will. Photo courtesy of Trek.
Getting way more rowdy on a fat bike than I ever will. Photo courtesy of Trek.

All of the new Farley models will be compatible with this new tire size thanks to the adjustable Stranglehold dropouts, so that at least is some consolation. There’s already some component support as well, with 27.5x80mm Sun Ringle wheels already available and other wheel manufacturers getting on board. Bontrager, Kenda, and Maxxis are already supporting this new push with compatible 27.5×4″ tires.

The new alloy Farley models will be available September 1 and the new carbon models will be available October 1.