Shoveling
the Bike Path
After
years of not having much success riding my road bike in the snow, I
discovered the seat could be raised high enough on my daughter's
mountain bike for me to ride comfortably. Although the bike
handled well
in new snow, compacted, icy snow with hundreds of footprints and a few
other bike tracks was a bit treacherous. I soon realized the
amount
of time it would take me to shovel the bike path would be paid back in
a few days of quicker and easier riding. Additional motivation
for this was the lack of any safe alternative route for a section of
the forest preserve path. I could go across town to safer side
streets but that would add almost 20 minutes each way on what is
normally
about a 30 minute commute.
My first test at clearing a path was
walking with a regular snow
shovel. This worked fine although the constant lifting and
dumping quickly tired my arms and back. Scraping the shovel on
the pavement for a mile or so also wore down the metal tip.
Heavier steel proved to be much more durable.
A Walking
Push Plow
My general
laziness and keen engineering skills soon came to good use as I
designed
a pushable plow that would roll the snow out of the way and not require
any lifting. It is like walking while pushing a baby stroller
although
in deep, wet snow it is like pushing a baby stroller carrying a 100
pound
baby who is dragging his feet.
Right Front
Front 
Rear 
Bottom
Front
Detail 
Extra
"Wings" 
Diassembled for Transport 
Detail of
Cargo area
The push plow with integrated shovel
holder. (Click on
any photo for a larger version.)
The shovel is useful for chipping away at drifted or compacted snow.
The rear box turns out to be a handy place to put my hat and jacket
once I start getting sweaty.
The "T" handle is removable so the whole unit fits in the trunk of a
Honda Civic.
The frame is made from 3/4" plywood and assorted 2x2 and 2x4 lumber.
The top cover is shaped from aluminum flashing.
The dark steel blade on front pivots on hinges to follow the contour of
the pavement. The square front has the disadvantage of catching
on most cracks.
The whole unit is about 16" wide. Although one can ride a bike on
a narrower path (and I did try a 7" plow), the snow tends
to fall back into the cleared area and bike pedals will hit any snow
deeper than a couple of inches. Most bikes need a width of about
15" to clear the pedals.
The orange front wheel was added after I realized the front blade would
gather a large mound of wet snow and the plow would become very
difficult to push. There is an additional set of "wings" that
bolt onto the rear to roll the snow out at a 30 degree
angle. Heavy wet snow tends to form fairly large (almost 12")
snow balls on the deck and they fall back into the plowed path if the
wings are not used.
This plow was used for four major snowfalls during the
2001-2002 winter season and performed well even in 7" of wet snow.
Take a look at a simpler and improved version called
The Drift Cutter .
A key lesson learned: Get out and clear the path soon after the snow
stops, before it gets walked on and compacted!
Something
faster is needed
The winter
of 2002-2003 started out with a light 1" snowfall. The push
plow did a nice job of clearing a narrow path but the effort of
transporting the plow down to the bike path, walking while pushing it
two miles
and bringing it back home seemed to be a bit of overkill for such a
light snow.
Since I commute to work on my bike, something I could carry with me
would be very convenient. I started experimenting with plows that
could be towed behind a bike. I considered this to be safer than
a front blade after my experiences jamming the push
plow on cracks and bumps in the pavement. The first test plow was
built out of vinyl gutter pieces. It had an apex angle (blade to
blade) of about 40°. Experience with the push plow proved
wheels
to be useful. I found inexpensive scooter wheels at a local
surplus
store. They met the requirements of being durable, narrow and had
nice bearings. The plow was pulled by a rope attached to the rear rack
on the bike. It had fairly low mass so the front tended to lift
every time the rope pulled taut. The plow would bounce as the
plastic
blades flexed and touched the pavement. The plow also tended to
swerve side to side since the rope provided very little lateral
stability.
With a 16" rear width, the plow ended up being almost too long
with
such an acute apex angle. The plastic blades became very brittle
in the cold and pieces broke off during the first test run but it did a
good job of clearing the snow off of the path.
After the first test run the essential features seemed to be:
- A rigid hitch for lateral stability
- A low angle hitch to
prevent lifting
- Wheels for a smooth ride
- Steel blade edges for durability
- Capability of folding up for transport
I
contemplated what an
appropriate apex angle would be. An equilateral triangle had an
appealing symmetry but I decided an isosceles right triangle would be
enough for light snow and would provide maximum outward velocity of the
ejected snow.
A
plow towed behind a bike.
This shows the plow deployed behind a bike.
The carriage bolts on top mate with the rear rack holes during
transport.
The photos below show the original hitch design but
click here to see the present
hitch.
Detail of the hitch attachment.
A triangular piece of wood
with slightly larger plywood sides is
captured in the stays ahead of the rear axle.
A piece of rope at the
joint near the tire provides a flexible
connection for cornering and tilt.
The metal bracket holds the tip of a shovel in case I want to bring one
along.
A bolt and wing nut secure the flexible joint when the unit is up for
transport.
The yellow wire just makes removing the bolt easier.
Detail of test ice breaking tooth.
The clearance is adjustable. This tooth helped keep the wheel low
but did occasionally catch on cracks. The stress of stopping the
bike eventually cracked the main hitch bar and so the tooth was removed.
Each steel blade meets the ground at a 45° angle. The sides
are made from two pieces of 1x6 (actual size 3/4" x 5-1/2")
wood fastened 90° to each other so the top of the blade
tilts out at a 45° angle. I added a filler piece of wood
to reinforce the joint. The cross section of the blade looks roughly
like three sides of an octagon. The blue plastic is from a cheap
roll up sled with the shiny side out. It helps keep wet snow from
sticking to the blade.
The plow flips up and rests on the bike bag for transit.
A bungie cord holds it in place.
Here are some higher resolution photos of the plow with a top mounted
hitch (no longer used since it caused tilting) and no plastic sheeting.
Bottom
Top
Front
Right Rear
Photos
on the Path
The plow in action.
(Action
photos courtesy of Gary Ross.)
A test scraper attachment is stowed on the top of the plow. It
attaches behind the plow and is designed to skim down the hard packed
crust that the main plow can't get.
This is what the plow does. Note the relatively clean ski tracks
to the sides of the plow track.
These photos were taken only three days days after a snowfall with wind
and drifting.
Here is what the path looks like where it is not plowed. Note the
ski tracks and foot prints.
And nearby where the plow has been. Again, note the ski tracks
and foot prints.
Ongoing Improvements
Wet snows in February 2004 showed the need for more lift
of
the exiting snow. After a few snowfalls the plowed path has deep
sides and the current design is not able to fling the snow over the
edges of the trough. Wet snow then tends to pile up in front of
the plow and can become heavy enough to stop the bike. You can
see that happening somewhat even with the shallow track in the action
photos.
A modification has been made to open up the outer top half of each side
to allow a more vertical and outward exit for the snow. A new
design is in development that will also shape the sides of the trough
outward similar to the action of the wings on the push plow.
I have received many requests for drawings or parts lists.
Click here to see more details and have a look at
the next generation!
Some comments
Although I did not anticipate this, I have received many thanks from
walkers, runners, bikers and even skiers. It seems people tend to
walk in the most compacted path. A plowed path keeps most of the
walkers out of the ski tracks.
I have noticed even dogs will prefer to walk in the clear track.
The plow does not remove the snow perfectly but it certainly is better
than nothing at all.
In general:
-
Dry pavement is easier
to ride on than snowy pavement.
-
Thin snow is easier to
ride on than deep snow.
-
Smooth snow is easier
to ride on than lumpy snow.
-
Smooth ice is easier
to ride on than lumpy ice.
Even during a cold spell when the temperature does not exceed freezing
for many days, the plow track will be clear and dry in a
day or two just from sublimation. The plow does not have to
scrape the pavement completely clean for this to occur.
I have been asked "Why don't you just drive the car when it is too
snowy?" There are many reasons why I decided to try to keep a
clear
path to ride on; the commute along the bike path is so much more
peaceful
than driving in traffic, it gives me an hour of (usually) low impact
exercise
at least 5 times a week, many of the side streets are plowed and
the bike path is a small but critical portion of the ride, and so many
other people can get out and use the path too.
Someone called into the Sound Off for the March 1, 2003 edition of the
Kane County Chronicle and said
"I want to thank the thoughtful person
or persons who, after a snowfall, shovels a single-lane footpath along
the east
side bike trail between Fabyan and Batavia. It makes our morning
walk
less hazardous and more enjoyable."
The latest. (Front part of hitch was being used on
another plow.)
Right Front
Front 
Rear 
Bottom
Front
Detail 
Extra
"Wings" 
Diassembled for Transport 
Detail of
Cargo area
Bottom 
Top 
Front 
Right Rear
