My Rambling Thoughts on Using a Snowblower with a Lawn Tractor

When I was looking at options for removing snow from my long driveway and sidewalks, I found out that many lawn, garden, and other small tractors can be fitted with a snowblower. However, I was frustrated that there wasn't a lot of discussion online in forums and blogs about owners long term experience moving snow this way. Having used this for several years, it seems like an appropriate time to write about this.

Background

I live on a flat property with a densely packed gravel driveway, paved roads, and sidewalks on gentle grades. I ultimately got a well used Craftsman tractor (ca. 1998) with a 19.5 HP briggs twin and a Craftsman branded 40" agrifab snowblower (Craftsman Model No. 486.24839), along with a ~50 lb barrel weight in a tray on the back to improve traction. I added a lugg handles kit and bolted an 50 lb disk weight (from craigslist) to each wheel, and a generic set of ATV tire chains for added traction.

 

My Experience

In a word: size

The major difference between using a lawn/garden tractor tractor and a walk behind snow blower is the length.

While it is pretty easy to spin a walk-behind blower in place, or simply walk it backwards in it's track, in all but the most shallow of snows, the tractor has two directions: blow forward or reverse in it's cleared track. Because the center of mass is not over the drive wheels, turning the tractor around to reverse the direction of snow removal is practically impossible in any snow that is worth attacking with the blower, as it will get mired.

When sharp turns must be made, a space has to be cleared so that the wheels can find purchase. For example, when clearing a side walk, the 90 degree intersection at a street corner cannot be navigated simply by turning the tractor in one smooth motion. Instead, the machine needs to be backed about 1 tractor length, cocked at an angle in the direction of turn desired to shave off a side of the snow bank, the moved forward until the blower is over the adjacent walk. This is repeated until the machine can make the turn, often require a huge amount of snow to be removed in the area between the two directions.

As mentioned before, the center of gravity is not well located for moving snow. The blower weighs north of 100 lbs (50 kgs), and is cantilevered over the front steering axle, counterweighted by the engine, driver, wheel weights, and barrel weight. This means that:

1. The front axle is always carrying a huge load, and that the steering gear is constantly stressed from steering the wheels with extra friction against the ground. 
2. It takes considerable extra weight on the rear drive wheels for them to be effective, as the blower gives the unit a tendency to pitch forward. 
3. When the blower is lowered, the situation is reversed, and the drive wheels pushing forward against the blower cause reduced weight over the steering gear, reducing steering forces while moving forward with the blower engaged.

As such, the operator needs to avoid situations that would require them to reverse up hill, as the least amount of traction is available under those conditions. Tractor using a snow blade are more able to cope with hills because the blade doesn't weigh as much, so there is more weight over the drive wheels, and they are shorter, and thus beating a hole big enough to turn the machine around in is a more viable possibility.

The fully equipped tractor is about 80" long and a bit more than 40" wide. The tractor has 60 lbs (25kg) of sand and scrap iron in the rear barrel and two 50 lb (20 kg) weights on lugg handles on the wheels for a total rear weight addition of 160lbs (~65 kg).

Aside from the poor maneuverability, the tractor/blower combination is generally less exhausting than a walk behind or a tractor/atv with a plow. The machine is carrying the seated operator, and the operator doesn't have to constantly lift, yank, and pull the unit to change direction, and there isn't the jarring that one experiences ramming into snowbanks with the plow at speed. In contast the tractor operation requires a good bit of concentration to manage the rate of forward travel, the direction of travel, and the angle and direction of the discharge chute, which are spread over 5 controls while the operator has one foot and two hands to manage them with.

 

 Required Engine Power

It seems like the 19.5 briggs twin is more than capable of driving the 40" blower. My determination of this is that in deep (>12") snow, the limiting factor in rate of travel was the ability for the tractor to feed snow from the first impeller stage into the second stage of the unit. The tractor would start pushing snow forward and start burning belts, but the engine would never stall or bog down. I surmise that engines with ratings better than 16 hp are probably capable of driving blowers up to around 50" with acceptable results. As far as I can tell the agrifab 2-stage and cub-cadet 3-stage blowers all use a common final impeller stage, which is what truly consumes the most power is the rate limiting part of the system.

That being said, moving snow uses considerably more fuel than mowing the lawn or towing a lawn sweep, and it seems like it uses about at least gallon of fuel an hour when doing heavy removal. One memorable >24" storm required 5 gallons of fuel to finally clear the driveway, the walks, and dig out the neighbors.

When the blower get overloaded, the snow in the second stage solidifies and can't fit through the opening in the chute, resulting in a jam, which in turn, results in the engine spinning the various belts against the seize front pulley, which causes the entire tractor frame to buck and flex, burning belts and sometimes causing pulleys to bend under the load.

The belt driving blowers can bit a bit fiddly to install correctly and the need assiduous attention to be sure they are aligned correctly and correctly pinned into the tractors frame. I have bent pulleys and burnt up belts from the reduction pulleys flexing under load. That being said, under normal, optimal conditions, the machine is sustain an arc of 40 or more feet of ejected snow.

Design of the Blower Unit

In two stage blowers, the first impeller stage sweeps snow from the front of the machine to the middle, increasing it's density by removing air, where a second centrifugal blower stage spins it up and then releases out of the chute. Each stage sweeps a volume of snow per revolution, and the smaller volume ends up being the limit on the machines maximum rate of snow removal.

The agrifab units (like mine) all appear to use a final stage impeller that is no wider or deeper than those used in push behind units that are half the width, and the same impeller is used by agrifab in their 50" wide blower. This means that when clearing deep snow, the rate of forward travel is limited by the loading/blowing rate of this assembly. In other words, you might be clearing twice the width, but you'll only be able to go half as fast. I've noticed that my neighbors tall 24" Ariens blower has a bigger second stage that is not as encombered when clearing heavy snow. Generally, the tractor is able to clear snow about as fast as it can move as long as the snow is around 2-6" deep but as the depth increases beyond that, the slower the tractor has to go to keep from overloading the blower stage. Another note is that the gap between the blower blades and the housing is about 1/2", which means that extremely wet snow isn't ejected well, as it simply flows out of the bower between the gap in the blades and the housing.

40" Two stage agri-fab snowblower attached to craftsman tractor

 A major gripe with the design of snow blower is the use of a 90-degree belt drive to it. Under load, the belts can slip or move across the pulleys, which can then either burn the belt or bend horribly. Some designs use a 90 degree gearbox instead (Cub Cadet/MTD OEM-190-032 has this, though curiously, the 3 stage
19A40024100 does not!), which I think would make the system considerably more reliable and robust.

The 90 degree belt line of a late 1990s agrifab/craftsman snowblower lawn tractor attachment

The belt drive system and general gauge of metal becomes a weak point when trying to break through plow berms. The prior owner clearly tried to ram a berm to break it up, and bent the side of the blower instead. Berms tend to have large ice chunks and are pre-compressed, they quickly fill the blower system and can block the chute or freeze in the second stage. The best approach is to work on berms before they freeze or turn slushy, Otherwise, it's more approachable to break them up with a shovel, then blow them to their final destination. I carry a piece of 1x3 wood with me to quickly clear the blockages in the impellers that develop.

The side skids shoes (sears 24279) that came on the blower were small to begin with and worn to nothing. I replaced them with larger and reversible Sears 784-5038A shoes, though I had to drill an additional hole to bolt them up. I am considering fabricating some castor wheels instead to make it easier turn the blower when it is operating.

Reliability - Fiddly

It seems like I need to fix something every few times I use the tractor to clear snow. Not always the blower itself, but often something on the drive-belt line becomes amiss. Thrown tire chains and snapped sheer bolts are pretty common. I can't recommend this to people who are not willing to work on equipment in the cold.

Also, the change over from mowing to blowing takes about 90 minutes. It's not hard, but you have to lay on the ground and fool with all the codder pins.

The tractor engine is very happy that it gets used year round: The tractor itself seems extremely reliable because the fluids are always fresh and it does not have an off season.

Final Thoughts

A lawn or garden tractor with a snowblower attachment seems suited to situations when there is a need to clear large areas that can be traversed in fairly straight lines. They operate best on level surfaces, uphill, or downhill with an terminal area where the tractor can clean a patch and get turned back around.

It's hard to argue that it saves space over having a separate lawn tractor and snow blower, as the tractor mounted blower unit, wheel and barrel weights, and associated equipment have a decent footprint. However, it does mean that the owner only has to contend with a single engine for all seasons.

Relative to a plow attachment, the blower is able to keep the same space clear over multiple storms, and is not as intimidated by having to move deep drifts. The blower also does not put the same wear and tear on the transaxle as a plow.  A plow weighs much less, and a tractor with a plow can handle steeper grades and won't become mired as easily if a u-turn in snow is required. For cleaning single width passes of powdery snow, or moving slush, the blade is likely more effective.

Relative to a rotary brush, the blower is not great for slush or shallow snowfall, and the brush can often clear a moderate snowfall to bare concrete where the blower is limited by the skid adjustment.

For clearing narrow walkways and single width or short driveways (100 feet or so), a walk behind is going to be a lot easier to manage. You'll spend your time effectively blowing and not trying to angle the tractor just so or get the thing free from being stuck in a small drift.
 

Other Reading
http://jayspower.com/library/2014/11/10/article-21-are-tractor-snow-blower-attachments-a-good-choice

 

Observation: Common Lawn/Garden Tractor snowblowers on the US market:

Overall, it seems like there is really a small number of blowers on the market.

Agrifab Blowers:
My blower is obviously a craftsman rebrand Agrifab. It seems like essentially the same blower is available today (though only in 42" width) in the form of the Agrifab LST42G.
The Agrifab blowers typically are of a two stage design, and typically feature a 90 degree belt direction change, driving the blower at the center of the impeller instead of a right angle gear set. They also typically have a 12" impeller stage and auger worm drive that appears to be similar design found in common walk-behind blowers. Another key characteristic is that they have a crank chute discharge and elation control on the drivers left handle, and a trigger locked lift/lower lever on the right. Collectively, their designs are targeted towards lighter tractors and mowers. They have thin sheet metal and plastic to limit the mass of the blower, and the volume of the impeller is small enough that smaller (both mass and horsepower) tractors can push them and move snow. There are variants with electric lift. It seem like they get branded Craftsman, Husquivarna, MTD, Toro, Arnold and Troy-bilt). I've seen 40, 42, and 50" sizes and an array of skid shoes.
Additionally, the two and three stage Cub Cadet blowers (like the 190-032-101 2 stage and 19A40024100) appear to be based off the 42" design, with stacked paddle style augers, a slightly higher inlet, a crucially, a right angle drive that is an improvement over the 90 degree angle belt train.


Bercomac Blowers:
Bercomac has historically made both one a two stage blowers for third party tractors, though now only markets two stage designs. Berco blowers look like they are physically heavier/sturdier than the Agrifab units (masses reach to about 300 lbs). They are characterized by generally have smaller skid shoes, steep augers that are exposed in a very square blower box.  Fixed shoot heights that can't be adjusted from the driver seat are also a Berco thing. I think some John Deere and other small professionally targetted blowers maybe of Bercomac origin, though I think the larger Deere blowers could be bespoke JD. The Bercomacs all have a 90 degree belt drive.

MTD:
Though I can't find them new at the time of writing, MTD made single stage blowers in the range of 36" to 42" until at least the late 1990s, and they can be found kicking around on the used market. The single stage has the auger blade on a drum that spins quickly, taking shallow bites of snow, and a very round shaped discharge chute.