Pavement Problems
by David L. Hough
 On
my cross-country trip last summer I was surprised to see that highways in
general have deteriorated over the past several years. One major hazard I
encountered was deep ruts in paved roads. And they were surprisingly hazardous.
Crossing North Dakota on US2, I encountered four distinct ruts matching the
wheel tracks of heavy trucks, for mile after mile. The left lane also had ruts,
but they weren’t as bad as in the right lane, so I’d move over into the left
lane when traffic allowed. But at one point my front tire hooked on a rut and
the bike headed for the right lane in spite of my attempts to hold it. One
instant I was in the left lane—the next instant I was in the right lane.
Fortunately, the right lane wasn’t occupied at the moment. But the unplanned
lane change really got my attention. Pretty unnerving at highway speed.
Road Ruts
I’d already encountered bad ruts north of
Toronto in Canada and on I-75 in Michigan, and I would find more ruts passing
through the Spokane area in eastern Washington. Apparently, both heavy trucks
and studded tires create ruts in the pavement, and road crews just aren’t able
to repave as quickly as the ruts are being generated. The ruts seem to be most
prevalent in northern central states and Canadian provinces where the
temperature varies widely between winter and summer.
Ruts are a special problem for motorcycles,
because of the steering dynamics. Ruts are also unnerving in a car, but easier
to control with four wheels and power steering. If you haven’t encountered
serious road ruts yet, you may wonder what all the fuss is about. But once
you’ve had the bike suddenly dart sideways in heavy traffic, you’ll be motivated
to understand what’s happening, and curious about managing such situations.
 I’ve
observed two different types of road ruts, which we’ll refer to as “truck” and
“studded tire”. Truck ruts are four distinct grooves matching the location of
the dual rear wheels on big commercial trucks. It appears that truck ruts are
formed by heavy trucks gradually pounding and squeezing asphalt pavement into
the rutted shape during the warm summer months, rather than tires wearing away
the surface.
Truck ruts are formed by heavy trucks
gradually pounding and squeezing asphalt pavement into a rutted shape. Tire
studs actually grind away the road surface in the tire track areas, creating two
wider, more rounded ruts.
Studded tire ruts are more common near big
cities where commuters regularly use studded tires during the winter months. The
studs actually grind away the road surface in the tire track areas, creating two
wider, more rounded ruts.
The problem for motorcyclists is that front
end geometry reacts in strange ways to the tire running in a rut. You may have
the bike weaving from one side of the lane to the other, or suddenly steering
itself into a new direction. And you’ll also get some curious steering feedback,
such as the feeling that the front end is momentarily resisting your pressure on
the grips. Let’s first think about why this occurs, and then we’ll make some
suggestions for maintaining control.
 Imagine
a tire riding in the center of a deep rut. So long as the tire contacts the
pavement in the center of the tread, the bike will steer straight ahead.
So long as the tire contacts the pavement
in the center of the tread, the bike will steer straight ahead.
 But
remember that with a two-wheeler, the front wheel constantly steers itself from
one side to the other as it maintains the bike in a balanced state. It’s not
much of a weave, but it’s a natural phenomenon with single track vehicles. The
point is, the bike won’t follow the center of a rut exactly. And when the bike
drifts over toward the side of a rut, the contact ring also moves farther over
to that side.
As the contact ring moves away from
center, the tire will drag more and more on that side, steering the front wheel
off center.
 As
the contact ring moves toward the side of the tire, the tire will drag more and
more on that side, steering the front wheel off center. For instance, the
contact ring moving position to the right will tend to steer the front wheel to
the right, out of the rut.
The contact ring moving position to the
right will tend to steer the front wheel to the right.
 But
remember that bikes tend to roll around the center of mass. So, the front wheel
steering toward the right will actually countersteer the bike into a left lean.
And in this situation leaning left will point the machine back toward the rut.
In this situation leaning left will point
the machine back toward the rut.
 Now,
with the bike steering itself back toward the rut, it probably won’t just center
in the rut and rebalance again. If the bike continues across toward the opposite
side of the rut, tire drag will again steer the contact ring out of the rut
(toward the left), and that will countersteer the bike back toward the rut
again.
As the tire swerves back across the rut,
tire drag will steer the contact ring left, and lean the bike back toward the
right.
All this off-center tire drag and leaning
causes the bike to swerve around in the lane. The feeling at the handlebars can
be startling, because you might be resisting the swerve, but the bike moves over
anyway. And if there are two ruts side by side (as with truck ruts), balance can
get very twitchy as the rider fights to keep the bike pointed more-or-less
straight down the lane.
As a general rule, the geometry of the front
end will tend to stabilize the bike after negotiating uneven pavement. But with
continuous pavement ruts, the bike may not restore itself to a balanced
condition until the tires are out of the ruts.
Potholes
Potholes (aka “chuckholes”) are formed when a
small area of pavement begins to deteriorate, and vehicle tires push the broken
fragments out of the hole. The hole forms very quickly in wet conditions,
because tires slamming down into the hole force the water (and debris) out like
a single shot from a powerful pressure washer. Potholes often form next to
railroad tracks, creating a serious bike hazard. Potholes are dangerous for a
motorcycle not only because the steep edge of a hole can push the tire sideways,
but the sharp edge can bend or fracture a wheel rim.
 Potholes
are a fact of life every spring in and around northern cities. The road has to
thaw before the maintenance crews can do any permanent repairs, and the only
workable temporary fixes are to pack gravel into the holes or throw a steel
plate over the hole, or both.
The temporary fixes before the ground
thaws are to pack gravel into the holes or throw a steel plate over the hole, or
both.
Frost Heaves
Another road hazard in northern climates are
frost heaves—big lumps of pavement pushed up into mounds by the freezing of the
wet ground beneath the road. Frost heaves are common every spring on Canadian
and Alaskan roads. Mounds up to a foot high can occur anywhere on the road, and
you don’t want to hit one of these lumps at highway speed. If you’re heading for
northern destinations in the spring, watch carefully and be prepared to swerve
between the frost heaves.
 As
with potholes, the temporary fix for frost heaves is to scrape the pavement
level, and apply a coat of gravel. On highways such as the Alcan, that means
several gravel patches every mile, for thousands of miles. In rare instances,
you’ll even get a sign.
On highways such as the Alcan, you can
expect several gravel patches every mile, for thousands of miles.
Crossing a short gravel patch isn’t a problem
unless it happens to be in the middle of a turn, one reason to keep speed within
sight distance when you’re off on an adventure in the wilderness.
Negotiating Surface Hazards
If it isn’t obvious, you need to maintain
enough following distance behind other vehicles to be able to see surface
hazards in time to change the bike’s line. But you know that in aggressive city
traffic, leaving some space ahead of you is simply an invitation for someone to
dive into it. The clever motorcycle commuter learns to search more aggressively,
but must also accept the probability of bike damage as part of the deal. That’s
why “commuter bikes” in northern climates tend to be “beaters”. The shiny bike
stays home in the garage until the weather and roads settle down.
A big part of maintaining control when you
encounter surface hazards such as ruts is to simply be aware of what’s
happening. Let’s say you feel the bike start to waggle around, and you wonder
whether it’s a bike problem or a pavement problem. Ruts are most obvious when
the sun is low on the horizon, casting shadows. And even if you can’t see the
ruts easily, you know they are most likely to appear in the wheel track areas.
Moving over to the center of the lane should confirm whether it’s a pavement rut
problem or a bike problem.
You’ll find it easier to control the bike on
a nasty surface if you’re in the habit of countersteering rather than just
thinking “lean”. That is, to make the bike move left, force both grips toward
the left. To make it move right, press both grips toward the right. Normally, it
only takes a modest push on one grip to cause the bike to change direction. But
when crossing a deep rut, or swerving between two potholes, it may require more
powerful pushes and pulls on both grips. Focus on countersteering to make the
bike hold it’s direction as the front wheel weaves it’s way into and out of the
ruts.
Riding the Ruts
 Even
on a severely rutted road, there are some areas of the lane that are typically
smoother, including the center of the lane, and the very edges of the lane.
Even on a severely rutted road, the center
of the lane and the very edges of the lane may be reasonably smooth.
So, one option for riding badly rutted
pavement is to stay in the center of the lane. Bear in mind that riding in the
center of the lane isn’t hazard free. Debris tends to get kicked out of the tire
track areas toward the center or sides of the lane. And the center of the lane
also collects more slippery stuff, such as oil or antifreeze drippings. It can
be a big shock when a tangle of truck tire tread, an AWOL muffler, or a dribble
of diesel oil suddenly appears ahead of you in the center of the lane. So,
remember to increase your following distance to allow more maneuvering room.
That also helps make you more visible to other drivers.
And what do you do when you come up behind a
slow moving vehicle? You’ll have to slow down or pass. But passing on a deeply
rutted road can be very unnerving, since the bike must wiggle it’s way through
several different ruts, each causing some strange feedback.
If you do decide to change lanes on a
severely rutted road, try to cross the ruts at maximum angle, more like the
tactics for crossing an edge trap or railroad track. Don’t try to ease over.
Rather, steer away from the ruts slightly, then swing back and attack them.
 The
best tactic for negotiating broken pavement and pothole-laced roads is to watch
the surface carefully, and dodge between the holes. Cars and trucks may not be
able to swerve around potholes, but a single-track motorcycle can often fit
between the holes, which tend to be worse in the wheel tracks of other vehicles.
All you need is a couple inches of level pavement between the bad areas.
Can you spot a decent path through the
broken pavement here?
Will the roads be better next year?
It would be great to hear that highways are
getting better rather than worse, but the truth is, major highways all over
America are deteriorating due to increased traffic, more aggressive driving,
heavier loads, higher speeds, and widespread use of studded tires. And repair
crews simply can’t keep up with the problems.
How About Bike Modifications?
There really isn’t much you can do to improve
the behavior of a motorcycle that’s trying to maintain balance on
strangely-shaped pavement. One thing you can do to improve your odds is to
ensure that the bike is well maintained. You might not notice a minor glitch on
a straight, level road, but in an abnormal situation even a minor problem can
contribute to loss of control. For instance, cruising down the superslab you
might not notice loose steering head bearings, but when you suddenly encounter
ruts, the bike may weave all over the road. Worn bearings, loose fasteners,
sagging shock springs, dry forks, and under-inflated tires will all reduce
stability.
The message is to keep your bike maintained,
not so much for the everyday ride, but for those abnormal situations in which
you expect it to perform at it’s limits. You already know to check your tire
pressures before every ride. Don’t forget to check your wheel bearings, head
bearings, and swing arm bearings, and snug up critical fasteners such as the
pinch bolts at the fork triple clamps and axles.
Once every year or two, drain and refill your
front forks, or at least top up the fluid. Flush and bleed your brakes. And, if
you’ve got more than 35,000 miles on your original shock absorbers, it’s
probably time to replace them.
Changing Routes
One primary tactic for badly damaged pavement
is simply to find a different road—preferably one less used by commercial truck
traffic. For instance, I’d been following US 2 across Minnesota and North
Dakota, and my original plan was to stay on 2 across Montana. But it turned out
to be a major truck route, and the pavement wasn’t tough enough for the job.
If I’d realized how bad the ruts would be on
US 2, I’d have turned off earlier. Finally, a few miles short of the Montana
border, I diverted south a few miles to pick up US200, a delightful two-lane
highway with only modest traffic. Since narrow 200 isn’t a favorite of the long
haul truckers, it hasn’t been pounded into ruts.
I wish I’d found an alternate route heading
west from Spokane, rather than staying on the Interstate. I could have turned
off onto US 2 for a few miles, then followed WA 28 and 283, quiet little state
highways with less traffic and less road damage. The State highways wouldn’t
have added more than an hour to the day’s ride, but would have been much more
enjoyable on a motorcycle.
Aggressive traffic on Interstates and major
US highways has already taken a lot of fun out of motorcycling. The older roads
are looking better and better for motorcycling, not only because of less
aggressive traffic, but also because of less pavement damage. If you encounter
nasty traffic or road damage on your next trip, get the maps out and think about
alternate routes. SR!
David Hough is a
long-time motorcyclist and journalist. His work has appeared in numerous
motorcycle publications, but he is best known for the monthly skills series “Proficient
Motorcycling” in Motorcycle Consumer News, which has been honored by special
awards from the Motorcycle Safety Foundation. Selected columns were edited into
two books, “Proficient
Motorcycling and
More Proficient Motorcycling, published by Bowtie Press. He is also the author of “Driving A
Sidecar Outfit”. A pocket handbook, “Street
Strategies” is also on the market now.
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