Shoveling the Bike Path

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.)

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.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 transportI 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.

Photos on the Path



Ongoing Improvements



Some comments



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 RearThe 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.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! 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."