Dry Trails Riding
Editors Note: The following article was originally sent to the ROMP email list for SF Bay-Area mtbers and subsequently published in their monthly newsletter. It is reprinted with permission from the author. I've done some minor editing to include local references but this is a great article on how to ride on trails during the summer months here in the Tri-Cities.
To: romp@cycling.org
From: Patty Ciesla
Subject: Dry Trails
Hi all,
It's been 6 1/2 weeks since I shattered my patella in Durango...
I've been out doing some physical therapy, hiking a lot the last two weeks, trying to loosen up the knee, and found myself staring at the ground with a whole different level of interest than usual. It's one of those things, that when your body ain't workin' quite right, you have to focus on simple little things like how and where you plant your foot on the ground.
Anyway, so I'm out there doing this little summertime meditation on dirt, and I noticed all the little cracks in the ground, and how crumbly and dusty everything is. Man, is it DRY! If the typical weather patterns hold, we won't get rain for months, maybe a few fogs is all, so conditions probably won't get any better for a while. I noticed a lot of long skid marks on a couple downhills. Somebody out there was having fun locking up the back wheel and dragging it through the dust and ball-bearings loose stuff that's accumulating in the ruts.
A couple of the trails I've been on are so dusty and loose they're nearly unrideable. What's going on right now is called "dry erosion". It's what happens when the ground starts crumbling because of the lack of moisture to hold the grains together. Soils with clay in them contract and crack, and the edges of the cracks fall apart with the weight of a foot or tire pressing on them. Little stones get kicked out as the finer material around them is worn away, and what once was hard dirt is now just a loose collection of dust and sand and gravel and rocks. Dry leaves and needles coming off the sagebrush, turn to powder after a few crunches under tire. They mix with the dirt and act like a lubricant for all the ball-bearing bits of rock, and you can get squirrely.
Where the trails are narrow and you really only have one line to ride, this dry erosion starts to create a groove where everyone grabs a little brake. You get stutter bumps before the corners, and ruts develop on steeps. Climbs become pushes because you can't get enough traction from one wheel. Well, I don't have to tell you this, cuz if you've been riding you've seen it. The thing is that in summertime, we have lots of light, school's out, and we're putting in a lot more mileage than we do in the winter, so this cumulative dry erosion may have a bigger impact on the condition of the trails over the course of the year than a few ruts from winter. The dust blows away and only the hard stuff is left behind. Once the rains start, the remaining material has much less glue holding it together, and it washes off the trail really easily.
But what to do about it? How can you practice low-impact mountain biking in the heat of the summer? Here are a few suggestions:
- If your tires are getting worn, get some new ones. Winter calls for narrow tires with good mud clearance. Summer calls for fatties. Big, fat sharp edged knobbies grab better and distribute the pressure over a greater patch of ground. They have a greater volume which keeps the rim just that much further from the rocks. Run enough pressure to prevent pinch flats (At 140 lbs I use 45-48 psi) but not too much more. Softer conforms better to the uneven ground and helps keep from skidding so easily. Save partially worn tires for when traction is better in the spring or fall.
- Check the damping cartridge on your shock. Look for oil on the bottom of your shock by the skewer. If your shock is not damped, it will rebound when the front wheel hits the bottom of the first stutter bump, and it will skip over the high spot only to land in the bottom of the next. If you're riding on the "Main Street" or "Big Tire" portions of the State Patrol Hill, you know how bad these braking bumps can get. Tune your fork for summer by increasing the damping to make it slower. This will help you ride over the tops rather than pogo from one hole to the next.
- Practice picking different lines than you usually would. Look for the high, hard lines. Sometimes the best place to put the rubber is right on the edge of the trail (but not OFF the trail!). Learn to ride close to trees, rocks, and drop offs without spazzing out and choking. Look ahead more, and plan your lines by scanning the ground. Once you commit to a line, look ahead again and just feel it roll past under you. Ride over some of the smaller rocks sometimes. If the rock isn't so big that you'll flat or get knocked off, you may find that the line over the top is better than either of the lines on the sides, because they've been dug out.
- Learn to use your brakes with finesse and planning. This means learning how to keep the wheels rolling. Locked tires are extremely abrasive. Rolling tires increase your ability to control your bike because you maintain rotational inertia, which works like a gyroscope to keep you upright, and helps keep the wheel rolling OVER the bumps instead of stopping and using them as a fulcrum for an endo! }:-o Look for where you can apply the brakes, and where you shouldn't. Learn to slowly let go of the brakes, so you roll and carry a little momentum through the sketchy stuff, rather than clutching your levers. Look ahead for a better braking spot, where you can feather off the speed you pick up. Use your front brake, especially when it gets steep. Get off the back of the saddle and lower your upper body down by straightening your arms and pushing back. This allows you to really brake hard with the front wheel without endoing because you've moved your center of gravity back and down. For loose stuff, you need to really feather and finesse your brakes, feeling the ground out. Sometimes you have to let off or hold on to one brake or the other just a little, but move your levers sloooowwwly, don't grab and drop.
- For climbs, move your butt forward onto the nose of the saddle, and lean over your stem. Hold your bar ends, and pull both down and back to use your upper body to leverage more weight onto the rear tire without lifting the front wheel off the ground. Do it evenly, don't rock side-to-side like roadies do, stay still. When done successfully, you can feel the work in your arms compress your rear tire. This creates a powerful bite on the ground that helps keep your rear wheel from spinning out. You can also stand up slightly to get even more forward for really steep stuff. Practice this position on a steep road if you can't get it to work for you in the dirt. It requires some work in your upperbody and quads that is very different from the normal feeling.
- If you can't climb or ride a loose section, don't trash the best line by hiking on it using your cleats for traction. Leave the hard lines for riding. Push your bike on that part, hold the bars and use your brakes and tires for assistance, and walk where it's already loose. Your feet can actually do much more damage than your tires given how you're steel-shod. While you're off the bike, kick the loose stones off the hard lines - they'll last longer if you do.
- In winter, we all slow down a little because we know the conditions aren't great and traction is iffy. Same deal now. Take it easy and back off the pace a bit, especially where it's loose.
Savor Sweet Singletrack!
   
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