On the World Famous Birkie Trail in Cable, Wisconsin!

The Fat Bike Birkie, Presented by Freewheel Bike, is the premier on snow bike event in North America. Riders test their skill and endurance on the professionally groomed American Birkebeiner Ski Trail!

THREE events to choose from: The Big Fat 47K, The Half Fat 21K, and the un-timed Fun Fat 10K Tour – there is something for every rider!

We remain committed to providing inspiring opportunities to promote a healthy active lifestyle and wellness events for all. 

  • We will take every safety precaution and measure to ensure the safety of our participants, volunteers, spectators, staff, and local communities.
  • See the Event Update page for information that has been developed for our other in-person events.
  • Stay tuned for specific Fat Bike Birkie information.

Fat Bike Birkie is an Open-Class Bike Race

There are no restrictions on the specific tire size allowed. The Birkie groomers are some of the best in the world and have the goal of providing a firm surface to ride on for the races. However, we cannot control the weather and the course conditions can vary widely, from hard packed to soft powder. Just like in the Birkie Ski race, Fat Bike Birkie participants are free to choose different equipment based on the conditions of the course. We recommend that participants be prepared to race in any course condition, on a bike equipped with at least 3.5 inch wide tires.

E-bikes are not allowed for any event of the Fat Bike Birkie on Saturday, however, may be ridden during Friday’s pre-ride of the trail only.

No special equipment classes will be recognized in the Fat Bike Birkie results or awards.  Tandems bikes are allowed, but there is not a special class and will not be eligible for awards.  Each tandem rider must register and contact registration@birkie.com to ensure the proper results are shown.

Event/Distance Options

The Big Fat 47K Race

The Half Fat 21K Race 

The Fun Fat 10K Tour

Fat Bike Birkie Start


2021 Fat Bike Birkie Registration

 May 1 through September 17September 18 through November 12November 13 through January 28January 29 until full or March 9
Big Fat or Half Fat Race$70$80$90$100
Fun Fat Tour$60$70$75$80

All Big Fat 47K participants must be at least 18 years of age on race day. All Half Fat 21K and Fun Fat 10K participants must be at least 13 years of age on race day.

Registration closes Tuesday, March 9, 2021 at 11:59 pm.

Register now to guarantee your Fat Bike Birkie t-shirt!

2021 T-shirt Design

2021 Event Changes

We are implementing many protocols and precautions to put on a safe event.  The Telemark Ascent, held in October 2020, was a successful in-person event that used many of the same precautions that we will use this time around. Changes include:

  • Drive-up bib pickup
  • No indoor spaces or outdoor gathering areas
  • Smaller start gates, separated by time
  • No aid stations (you will receive energy at bib pickup to carry on course)
  • Sack lunch and beverage to go after finish
  • No spectators allowed
  • Masks will be required in the start and finish areas
  • Gathering is discouraged in start/finish areas.  Please arrive no more than 45 minutes before your start.  Warm up as physically distanced as possible, leave your vehicle 10 minutes before your start time, and enter the start corral at your assigned time (5 minutes before your start). Upon finishing your race, please continue through the finish gateway, collect a drink and sack lunch to enjoy on the way to your vehicle!

Race/Event Change Request

The deadline for requesting a change in race/event distances is Wednesday, March 3, 2021 at 4:00pm CST.  Click here to submit your request.

Protect Your Registration!

Get reimbursed up to 100% on your registration if you can’t compete for a number of reasons.  Next Wave Insurance offers Regsaver so you can insure your non-refundable registration fee in the case injury, illness, or another covered peril occurs.* Please see policy for complete list of covered perils at www.registrationsaver.com/birkie. Limitations and exclusions apply. Next Wave Insurance, CA License #: OF00755.

Regsaver - An AIG insurance policy to cover your registration fees - Learn More

Learn More About RegSaver Registration Protection!

2021 Birkie Gear BagSold Out!

It’s Back for 2021!  Everywhere we looked during Birkie week 2020, we witnessed skiers using their awesome reusable Birkie gear bags!  This year, as part of our ongoing Birkie Green initiative we’ve designed an all new custom Birkie gear bag with SWIX!  The reusable Birkie gear bag is available for $47 and only during registration for the Birkie, Korte, Prince Haakon and Fat Bike Birkie.  Through your support, over 10,000 Birkie gear bags are now in use, keeping thousands upon thousands of plastic bags out of landfills. Thank you for your support of Birkie Green!

Birkie Gear Bag

Birkie GreenAs part of 2021 race registration, ABSF members will automatically receive a copy of the 2021 Birch Scroll® magazine. If you are not a member and would like to join the ABSF or would like to purchase a copy of the 2021 Birch Scroll results issue, you may pre-order a copy during your race registration process. As part of ongoing Birkie Green initiatives, all registered participants will receive a digital copy of the 2021 Birch Scroll magazine.

Fat Bike Expo & Bib Pick Up

There will be no Fat Bike Expo in 2021.  Bib Pickup information will be available soon.

Course Information

Both races and the Tour will start and finish at the American Birkebeiner Trailhead in Cable, WI.

No aid stations will be available on-course in 2021.  Please carry your own hydration and energy. GU and Clif bars will be given at bib pickup.

Cut off time is 2pm for all events.

The Big Fat 47K course will ride out on the Birkie Classic Trail after the Powerlines and return on the Birkie Skate Trail to the Powerlines where it will come into the finish on the Birkie Classic Trail and Kortelopet In trail to the new Birkie Finish Stadium. The Half Fat 21K course will ride out the Birkie Classic Trail after the Powerlines to Timber Trail where it will enter the Half Fat only course.  The Fun Fat 10K Tour will ride on a mix of Birkie Classic Trail, smaller ski trails, and the Half Fat course before finishing the same way as the Big Fat 47K and Half Fat 21K races.

Interactive Course Map

Experience the race again or for the first time! Roll over the epic hills on the legendary Birkie Trail, witness the race rollout, ride along with the pace cameras, check out the Half Fat 21K and Big Fat 47K courses, and feel the rush as you virtually ride the Fat Bike Birkie. This interactive map experience has it all!

The race course will be ridden clockwise starting with the Birkie Classic Trail and finishing on the Birkie Skate Trail!

View Interactive Course Map »

Pre-Riding the Course — When & Where

The Fat Bike Birkie Race Courses will be groomed and marked for pre-riding on Friday, March 12 from 10:00 am to 3:00 pm.  Please follow signs carefully.

Please note that riding bikes on the Birkie Trail during the winter is only allowed on the days designated for the Fat Bike Birkie event. However, winter bike riding can be accessed from many of the trailheads utilizing the Chequamegon Area Mountain Bike Association trail system. Trail conditions can be found on the CAMBA Winter FAT BIKE page.

Start Gates

Riders will be assigned to multiple start gates based on the last 3 year’s of Fat Bike Birkie results for all races.  Gate qualification times will be available in January.  Gate sizes will allow for a physically distanced start.

Full Fat Start Gates:

  • 9:00 am start
  • 50 riders/5 minutes
  • Based on finish times of past 3 Full Fat or Half Fat races
  • will be assinged in early March

Half Fat Start Gates:

  • 10:00 am start
  • 50 riders/5 minutes
  • Self seeded based on expected finish time- If you hope to be the Half Fat champion, please choose the 10 am start time.  If you did not choose a start time during registration, you will be sent an email with information.

Fun Fat Tour:

  • 11:00 am start
  • 15 minute start window for a relaxed and physically distanced start

The Big Fat (47K) race will feature 9 start gates of 50 riders.  Riders will be placed in one of these gates based on their best finish time from the previous 3 Big Fat or Half Fat (21K) races.  Riders without a result in the past 3 Big Fat or Half Fat races will be assigned to Gates 7, 8, and 9.

2021 Big Fat Gate Assignments based on BIG FAT results

Start TimeBig Fat Gate2020 Big Fat Finish Time2019 Big Fat Finish Time2018 Big Fat Finish Time
9:00 AMGate 11:41:10 to 1:56:201:46:27 to 2:02:251:48:11 to 2:04:25
9:05 AMGate 21:56:21 to 2:08:282:02:26 to 2:15:112:04:26 to 2:17:24
9:10 AMGate 32:08:29 to 2:22:382:15:12 to 2:30:062:17:25 to 2:32:32
9:15 AMGate 42:22:39 to 2:35:472:30:07 to 2:43:562:32:33 to 2:46:36
9:20 AMGate 52:35:48 to 2:56:012:43:57 to 3:05:132:46:37 to 3:08:15
9:25 AMGate 62:57:01 +3:05:14 +3:08:16 +

2021 Big Fat Gate Assignments based on Half Fat results

Big Fat Gate2020 Half Fat Finish Time2019 Half Fat Finish Time2018 Half Fat Finish Time
Gate 249:18 to 56:4153:58 to 1:02:0455:48 to 1:04:10
Gate 356:42 to 1:02:361:02:05 to 1:08:321:04:11 to 1:10:52
Gate 41:02:37 to 1:09:301:08:33 to 1:16:061:10:53 to 1:18:41
Gate 51:09:31 to 1:15:551:16:06 to 1:23:071:18:42 to 1:25:56
Gate 61:15:56 +1:23:08 +1:25:57 +

Elite riders may request to be placed in Gate 1 at any time by sending a request and credentials to registration@birkie.com.  Riders will be placed on a wait list and notified of placement in February.


Presenting Sponsor

1up USA
Northern Lakes Cooperative
Backroads Coffee


Want to get involved, see this event up close and personal, and be part of what makes Birkie events great? We’d love to hear from you! Contact the Birkie at 715-634-5025 x:2,1 or click here for available shifts. There is no obligation — we’re happy to answer your questions. Contact us today!


Please contact us with any questions at birkie@birkie.com or 715-634-5025.