As autumn approaches and we begin to think about snowy days, groomed track and whiteout conditions – only one thing comes to mind, fat biking. Being able to take your favorite sport year round, no matter where you live and in what climate, is priceless. Even though fat bikes were originally designed for on-snow and sand riding, manufacturers in the last year have been putting a heavy focus on creating fat bikes for all seasons and conditions. Although the Fatback Corvus is a rigid bike and hasn’t gone by way of suspension as other companies have – it has proven to be a great all season bike. Fatback Bikes had their start in 2007. They were one of the pioneers in the industry and have continued to raise the bar as far as big tires go. At the inception of their brand, the only other all terrain bike on the market was the Surly Pugsley, and a few other custom builds. Fatback set out to design a bike that had a more comfortable ride, beginning with the creation of the 170mm symmetrical rear, followed by the 190mm and 197mm rear which has become an industry wide trend. The Carbon Corvus had it’s release in early 2014 as a race-ready all-terrain fat bike. The Corvus is light, but Fatback stands firm on not compromising the dependability of their bikes for a few extra grams. They designed the frame using a unidirectional carbon fiber layup, with a monocoque front triangle to insure the strength one needs to carry a load of gear. The frame also comes with 3 bottle mounts with one on the downtube as well as two rear rack mounts. As any backcountry race ready bike, the Corvus XO1 is stocked with sensible components. For starters it comes with a simple 1X XO1 driver with grip shifter. The grip shifter were great for the winter months and proved to be very friendly when installing and using pogies. The driver is rounded out with Race Face Turbine Cinch Cranks and a 32 tooth chain ring. It also came with Avid BB7’s, maybe not the best working break out there, but one that can be serviced in the field, a benefit when bikepacking. Winter Performance I was able to take the Corvus into the field on some extended day rides throughout the Crested Butte area testing the bike on groomed trail, packed forest roads and snowmobile track. I was very happy with the way the Corvus performed in it’s natural habitat. The stiffness of the frame allowed you to pop out of the seat and take off up some steep groomers. It is a really quick bike. Through punchy snow or during warmer conditions I would recommend switching out the stock Maxxis Mammoth tires for some Dillinger 5’s since the bike can handle 5″ tires. Although the Maxxis Mammoths performed well on firm groomers, they sunk into soft snow too easily and with little traction. On the other hand, the Mammoths are great for dirt riding. Read our full review on the tires here.Depending on where you are riding, the 32 tooth chain ring can be aggressive – it was tough for some of the winter riding in Crested Butte. In most other areas you may be fine. I did start to notice some issues with the rear thru axle coming loose while grinding on steep climbs in the winter – more on that later. Overall, the Corvus is a quick to respond, lightweight and comfortable fat bike for winter conditions.Summer and the Long Haul Throughout the Spring and Summer I hopped on my Corvus in lieu of my regular mountain bike for a change of pace. The big summer weather test for the Corvus took place on the 100 mile White Rim Trail in mid-April. I was really excited to take this rig bikepacking. After experiencing such fun winter riding, I thought it would be the perfect tool for the job. I decked out the bike with a custom designed frame bag from Becker Sewing and Designs and a Jones Loop H-Bar, packed my things, and was off to Moab with a few of my best friends. Riding the trail in a counter clockwise direction, we began with a descent down Mineral Bottom. The bike was comfortable – like a couch. I was ready to spend the next 48 hours getting to know the Corvus.The light design of the bike really helped me save weight and not feel so fatigued during any hike-a-bike sections. The frame space on this bike is a huge plus. I am 5′ 5” and ride small frame bikes and it is rare to see a bike (even a hard tail) with this much space in the front triangle. On the second day I started to experience the issue with the thru axle coming loose, as I had during the winter. The thru axle kept loosening and we kept tightening it without over tightening. At one point while ascending a small hill it became so loose that the free hub body popped out of the actual hub, and a few of the pawls disintegrated. I was stopped in my tracks and fell over. Luckily I was riding with a couple of mechanically versed riders who were able to fix the issue temporarily – although I dealt with the thru axle slowly coming loose for the remaining 50 miles of the route. Overall Summer and long haul performance is still very positive – regardless of the rear hub situation. The bike shifted well, was quick and responsive even while loaded, and was comfortable. I would recommend ordering your Corvus directly through Fatback and having them build up a custom wheel set around an Industry 9 hub – an option on their website. The Fatback Corvus is successfully designed to do exactly what it is intended to – to be a lightweight all-terrain fat bike. The next test will be to convert it into a 29+ this fall for a different perspective.