Race Rules

Race rules are designed to provide a safe and fair experience for everyone involved and to help ensure our ability to produce the race again next year.

Major rule infractions by racers will result in immediate disqualification of the racer. Please do not argue with or harass our volunteers but feel free to direct any questions or complaints to Nick and Pete at racedirector@gnarrunners.com.

Course Cut Off

The 50 mile race will be limited to 14 hours and will end at 7:30pm.

Course cut offs will be enforced at the following aid stations:

  • Soldier Canyon (Mile 25) at 12:15pm. 6:45 Total time.
  • Arthur’s Trailhead (Mile 32.4) at 2:10pm. 8:40 Total time.
  • Horsetooth Trailhead (Mile 39.6) at 4:35pm. 11:05 Total time

This is a challenging course and many runners may find it difficult to meet these cut-off times. Any 50 mile runner who drops out or fails to meet the course cut offs after completing the first 25 mile loop will be given an official finish time in the 25 mile race.

Note: Course cut offs should not be used for pacing targets to reach the finish in 14 hours. We have set these cut offs to give runners the maximum time on the course. To finish under the cut off, runners need to hit the 25 mile turn around before Noon, Arthur’s before 2pm, and Horsetooth before 4:30pm.

Bib Numbers and Check in

  • All Runners are required to check in prior to the race start. Runners who do not check in will not be officially entered into the race and will not be recognized in the final results.
  • At each aid station, volunteers will record runner bib numbers. Runners are responsible for making sure that aid station volunteers record their number. Please make sure that your bib number is visible from the front and call out and confirm your number when passing through an aid station. This is important so that we can keep track of runners and know that you are not lost or injured.

Dropping Out

  • If you need to drop out of the race for any reason, you must check out with the nearest aid station or course volunteer. If you do not inform us that you have dropped, we will assume that you are lost on the course.


  • There will be no water cups at the aid stations. Bottles can be filled at aid stations. Bottles or other supplies may not be stashed along the course. All runners must have the capacity to carry a minimum of 20 oz of water, whether in a bottle or a hydration pack. Dixie cups will be available at aid stations for carbonated beverages, but they cannot be carried out of the aid station.

No Headphones or iPods

  • Per the terms of our insurance coverage, we must ask that you do not run with headphones. This will be a pain in the rear end for some, we are sure, but the sounds of nature are part of the experience too.


  • Purposeful littering is prohibited and will result in an immediate disqualification. Any litter left on the course may jeopardize our ability to continue to host events on public trail systems. Carry garbage to aid stations and dispose of trash in proper garbage containers or hand garbage to a volunteer. We recommend that you carry an extra baggie to stash small wrappers and gel tabs that can easily be dropped by accident.

Stay on the Trail

  • No bushwhacking or short cutting. Do not leave the trail when passing other runners. In case we have wet trail conditions, please run through any muddy sections to avoid widening the trail and causing further erosion. (This is a trail race, leave the clean road shoes at home!)

Yield to Pedestrians and Horses

  • The trail system will be open to the public during the race and a single complaint may jeopardize our ability to host this event again. Pedestrians and Horses always have the right of way. Please be courteous and respect other people on the trail system. When approaching horses, talk to the rider and always wait until they give you permission to pass. Most riders will move their horses off the trail for you. Always try to assume higher ground when crossing paths with horses.
  • Mountain bikers are required to yield to runners but for your own safety, please use common sense and watch for blind corners and be careful when passing bikers.

Yield to Faster Runners

  • There will be some two way traffic as the 50 mile runners reverse direction on their second loop. Please yield to the faster oncoming runners. If being caught from behind, step aside where possible to allow the runner to pass.


  • Pacers are not allowed on the course and will result in the immediate disqualification of the runner.


  • Runners may not receive any additional crew aid outside of designated aid stations. Crewing on the course will result in the immediate disqualification of the runner.
  • Crew access is available at the Arthur’s Rock aid station, Horsetooth aid station, and the Soldier Canyon finish area (for 50 milers). Crews are welcome to assist aid station volunteers to help their runner.
  • Parking may be limited at the Horsetooth trailhead and crew access is not guaranteed. Runners should not rely on crew for any critical supplies and should plan to send these items in a drop bag.

Trekking Poles

  • This is a running race. No mechanical aid (poles, traction devices, etc.)

Drop Bags

  • Drop bags may be sent to the Horsetooth aid station (mile 10.4 and 39.6). Runners should drop off their Horsetooth drop bags at race check in by 4:45am.
  • Runners may also leave a drop or finish line bag at the Soldier Canyon start/finish area.
  • Please limit your drop bags to the size of a small duffel bag, day pack, or stuff sack.
  • We will not be responsible for any lost or stolen items so please do not leave any valuables in your drop bags.


  • Dogs are not allowed on the course with runners. Well behaved dogs on leash are welcome at the park trailheads.


  • Park restrooms are available at the Soldier Canyon, Arthur’s, and Horsetooth trailheads. Additional portable toilets will be available for race participants at the Soldier Canyon and Arthur’s trailheads.


  • Please do not leave any valuables at the start/finish or aid stations. Volunteers are not responsible for returning items left behind at aid stations. We are not responsible for any lost or stolen items.

Cancellation & Refund Policy

With the exception of wait list transfers, entries are non-refundable and non-transferable. In the event the race is cancelled due to extreme weather, fire, or for some other unforeseeable event, we cannot offer refunds or credits. See our registration page for our wait list transfer policy.