IB13: Borealis Yampa SL Fatbike is Insanely Light, Fast, and Tubeless
When we spoke with Adam about the new Borealis Carbondale tubeless fatbike rims just before the show, he told us they would have an SL Yampa build under 23 lbs. The truth? The bike is actually 21 lbs 9 oz, without going to extremes on the build.
Get the scoop on possibly the lightest fatbike around and check out the Carbondale rims first hand, next.
Borealis conveniently had a stand equipped with a scale to see the lightness first hand. The early samples of the Carbondale rims weigh 570g just like Adam claimed.
The tubeless carbon rim is actually pretty interesting with tubeless tape not even needed under the bead of the tire. So far Borealis has been using packing tape but plans to have Stan’s tape made in the best size. Their current set ups run tape only as wide as the spoke holes with the tire bead resting on bare carbon. With one scoop of sealant per wheel the tires have stayed inflated nicely.
While a selection of lightweight components have been assembled, nothing is particularly crazy. An XX1 drivetrain sits next to XX brakes and Truvativ Noir carbon bars and seat post. A 3t stem, ESI grips, a carbon Selle Italia saddle, and Race Face Next carbon crank are also used. Wheels are Borealis’ Carbondale rims laced to their own hubs. 45NRTH Husker Du tires are set up tubeless with Stan’s sealant. Oh and it’s a large frame.
All that and it’s still rack compatible. Metal threaded inserts bonded into the stays will accommodate a rack.