Backcountry snow riding comes with rewards and challenges. Unlike groomed trails at a Nordic center, in the backcountry there are no hard and fast rules, but we can do a lot to “self-groom” a trail to be awesome (or trash it so it’s basically unrideable). Here are a couple tips on packing and etiquette that will make your ride more enjoyable and leave the trail in the best possible condition for others.
BMA worked with the U.S. Forest Service Boulder Ranger District to come up with educational winter trail etiquette signs at trailheads for all users to let them know what to expect and how to treat the trails. Here’s a couple more tips for fatbikers so you don’t “Hulk smash” the trails!
First, what makes a good trail to ride? Mostly, the trail has enough traction so you can pedal and roll without wiping out and (maybe) it’s wide enough so that you can put a foot down next to your bike without falling over into three feet of powder. Some trails are packed wider (like Mud Lake), some narrower (Ceran St. Vrain).
So, how do we make trails that are packed like that?

Don’t leave a ruttin’ mess!
Unless you are riding extremely hard packed snow/ice, you are going to leave a track – that’s just fine. But, when you leave a rut, you make a channel in the packed trail like someone digging a ditch in your yard. That counts as a level two thrashing of the trail! Ruts can make trails unfun at best and unrideable or dangerous at worst. These ruts can freeze into the trail pack and remain for weeks, sometimes hidden by just an inch of fresh snow.
When you ride in fresh snow at a proper pressure, you pack the new snow into the trail, leaving a flat track.

So how do I lay a flat track?
Big tires and loooow tire air pressure. The deeper the fresh snow or the softer the conditions, the more your tire pressure matters. For Boulder County backcountry riding, we recommend at least 3.8”-wide tires and strongly encourage 4.5+”. As for PSI, on a groomed well-packed track you might run as much as 6 or 7 PSI (it ain’t a mountain bike, so forget about this crazy 10-15 PSI stuff, folks). On softer backcountry trails we recommend starting at 5 PSI and dropping until you can ride without slipping or making a rut. That could be as low as 1 PSI! And sometimes, even that isn’t enough.

So if I have to walk, do I need to turn back?
Not necessarily. After a snow or wind storm, some sections of trail are going to be drifted and deeper/less packed than other sections. If you need to walk some short sections, please walk as much to the side of the trail as possible (or even off), on the uphill side and roll your bike in the middle of the trail. That way your boots won’t make posthole divots in the trail. Bonus points for groups walking on the same side of the trail. If the trail conditions don’t improve, it’s time to flip your bike and head back out or strap on your snowshoes to continue on.

Is there a way to help pack a trail if the snow is too deep or soft to ride?
Absolutely! Lots of fatbikers carry snowshoes with them. Ride on the trail as far as you can without making a mess of it and then park the bike and grab your snowshoes. Then, take one for the team by snowshoeing out a ½ mile or so. A lot of the time just a couple snowshoe tracks can pack in a trail well enough that the next group can ride on what you packed! When you snowshoe, walk in the middle of the trail and roll your bike to the side (or just park the bike), since you (hopefully) weigh much more than your bike and your body weight will pack the trail better. Also, when you pack a trail think about people riding their bikes – don’t pack the trail so close to low branches on a tree that the next fatty to roll by is going to get their noggin knocked.

There sure are a lot of “tips,” why do I need to follow any of them?
Mostly, because riding on thrashed trails is nearly impossible. So, if you’re doing the thrashing, you’re going to make it worse for everyone (including yourself). Also, fatbikers are the new kids on the winter block scene. Right now, almost all our USFS winter trails are open to fatbikes and we don’t want that to change. When in doubt be nice, say hi and let’s make sure all users can enjoy our winter trails.