How To Mow Hills With A Zero Turn Mower (Learn The Dangers)

All riding and walk-behind mowers can be dangerous on hills if the right safety methods are not followed.

Tier List: The Safest Lawnmowers on Hills

Here is a tier list of the best and worst lawn mowers on hills.

  • Lawn tractors are the worst on hills because they have less traction, smaller wheels, no diff lock, are 2 wheel drive and have a higher centre of gravity.
  • Standard zero turn mowers are better than lawn tractors but still have many dangers when mowing on hills. With their lower centre of gravity they are less prone to flipping over on steep hills.
  • Most standard garden tractors have diff locks, 4WD and large rear tires so they are the best option (when it comes to standard homeowner style riding mowers) for mowing on hills because they won’t lose traction.
  • GrandStand mowers are great on hills because you stand at the back of the mower and can easily transfer your weight into the hill to counterbalance. You are also adding your weight to the back tires to help gain traction.
  • Self-propelled mowers are the least dangerous on hills because they are light and easy to dodge if they flip over. They also have a low centre of gravity and are easy to control.
  • Some commercial zero turn mowers are rated up to 25° massive slopes because they have been designed with dual rear tires, weighted front wheels, 4-wheel steering, 35 HP engine and self levelling operator seat
  • The industry standard for mowing on hills are the hydrostatic powered walk behind mowers. These are large commercial walk behind mowers that use a hydraulic pump to power the mower so you just walk behind it. They have the benefits and safety of a walk behind mower while still cutting up to a width of 60 inches.

Today we will focus on the dangers of zero turn mowers on hills and talk about how to mow hills safe with one.

Mowing Guide: How Steep is a Hill?

We will define hills by the angle they would make with flat ground.

  • 0° is flat ground
  • 3° – 5° is a small hill
  • 6° – 10° is a big hill
  • 11° – 20° is a massive hill
  • 21° and up is an extreme hill

You can get a feel for how steep those angles are – and begin to understand how the dangers of zero turn mowers on different hills is serious – by looking at the chart we put together below:

Defining hill steepness for mowing

Zero turn mower manufacturers will tell you in their User Manual what slope rating the zero turn mower is rated for. From our research all zero turns are rated for 15°.

There is one lineup of zero turn mowers from Cub Cadet with four wheel steering (and a steering wheel) that is rated for 20°. The four wheel steering means all wheels are engaged and will not lift off the ground when turning.

Let’s look at some other riding mowers and their slope ratings:

  • Good up to 15° – 4WD garden tractors with diff locks
  • Good up to 20° – Zero turn mowers with four wheel steering
  • Good up to 25° – Zero turn mowers with 6-wheels (dual rear) and 4-wheel steering

Now we have defined what we are calling steep hills let’s move on to how it is recommended you mow a hill with a zero turn mower.

3 Big Hill Mowing Techniques (Hills Above 10° Incline)

  • Any hill with less than 10° incline is low risk and you can follow whatever technique you prefer.
  • Above 10° the manufacturer will have recommendations for how to mow hills in the User Manual.
  • Below are the most common recommendations. 

Whether you’re on a zero turn mower, walking behind a push mower or riding a garden tractor there are only 3 options to mow a big hill:

  1. Parallel to the hill (up/down)
  2. Perpendicular to the hill (across)
  3. Diagonal to the hill – in between parallel and perpendicular.

Let’s look at the pros and cons of each technique and which lawn mowers are recommended for each technique:

1. Parallel With The Hill Incline – Up/Down

The Parallel to the incline mowing hills technique
  • This is the recommended technique for all lawn and garden tractors, ride-on mowers and out front mowers.

The reason is because lawn and garden tractors have a high centre of gravity.

They want to flip over and crush you if you mow steep hills going across or perpendicular to the incline.

Also, their weight is well balanced front-to-back so when mowing up the hill or down the hill (as long as you stay within what incline the mower is rated to) it won’t flip over.

Pros:

  • Keeps tractor mowers from flipping over
  • Allows capable lawn and garden tractors to mow up to 15° hills

Cons:

  • Less efficient
  • Horrible traction with steeper heals and less than ideal conditions
  • Can gain a lot of speed on the downhills

2. Perpendicular To The Hill Incline – Across

The Perpendicular to the incline mowing hills technique
  • This is the recommended technique for zero turn mowers.

Zero turn mowers have a wider base and much lower centre of gravity than other ride-on mowers.

This allows them to be able to mow hills across – perpendicular to the hill incline. This is more efficient because you are not having to go up hills (losing traction) or break going down hills (added transmission and break wear).

Some zero turn mowers are designed for hills with 4-wheel steering and dual rear tires. These commercial-duty models are rated up to 25° hills.

Pros:

  • More efficient
  • Low risk of losing control because not going downhill

Cons:

  • Tipping risk is still there although made small by low centre of gravity of zero turn mower

3. Diagonal To The Hill 

The Diangonal to the incline mowing technique

This isn’t the manufacture recommended hill mowing technique but it can be a great technique for some situations.

For example, look at the picture above. To mow around the trees a diagonal will need to taken to around it.

Pros: 

  • Allows zero turns to get around obstacles while still maintaining safety
  • Allows riding mowers to get around obstacles while still maintaining the preferable aligned up/down the hill

Cons:

  • Zero turn mowers without 4-wheel steering should only turn on hills less than 10° hills
  • The lawn stripes will look weird

Mow To Your Situation

With these hill mowing techniques you will always have people that swear by doing things one way or the other. In general, they are not wrong or right. The above techniques is what is recommended by the manufacturers. If you’re have specific knowledge how to mow your specific hill safely then you should do what you feel the best doing.

10 Dangers of Zero Turn Mowers on Hills (And how to reduce the risks)

Take a look below at the 10 main dangers when using a zero turn mower on hills. In bold is the danger and after how to reduce the risk of an accident.

  1. Losing control going down a steep slope. Mow across hills not up/down when using a zero turn.
  2. Not paying attention and having to break quick on a hill. Try to maintain constant slow speed on hills or you list losing traction and control.
  3. Hitting a rock or huge bump hidden under high grass. Make sure to walk the mowing path to look for hidden obstacles.
  4. Losing traction and sliding down the slope when grass is wet. Do not mow hills when grass is wet.
  5. Risk of zero turn mower flipping over. Go extra slow around trees and when making turns on slopes.
  6. Grass catchers can cause instability. Don’t use grass catchers on steep hills.
  7. Thinking you can help stabilize the mower by leaning into hill or using your foot to help push. The hill is far too steep for your mower if you feel the need to do this. Do the job with a more suitable mower.
  8. A ditch wall collapses or sandy cliff/embarkment gives way. Do not mow slopes and get close to ditches, water or cliffs/embarkments.
  9. Turning downhill on the wrong zero turn mower may cause it to flip forward since they tend to be rear heavy. Only turn going uphill and go as slow as possible.
  10. Starting and stopping on a slope will cause immediate danger and loss of control. Do not stop or start on a hill.

How To Mow Hills Safely With a Zero Turn Mower

Simply put: Don’t mow with a zero turn mower if your specific model is not rated for how steep the hill is. Use a regular walk behind mower or string trimmer that is much safer on very steep hills.

But if the hill is right at the edge of your zero turn models rated steepness – say 15° – then here are some tips for safe mowing:

  • Go slow
  • Mow across the hill not up and down
  • Don’t mow when it is wet
  • Make turns going uphill
  • Do a walk around before mowing to see for holes, rocks etc.
  • Do not stop or start on a slope.

Know the dangers and know how to reduce the risk of those dangers turning into an accident.

Wear you personal protective equipment and hearing protection headphones.

Don’t get over confident and take risks you don’t need to.

Best Mowers For Mowing Hills

  1. Cub Cadet Pro Z. The best zero turn mower to reduce dangers on hills.
  2. A regular reel mower or walk-behind mower will be safest but will take the longest and be the hardest work.
  3. Then comes the hydrostatic walk behind mower which uses hydraulics to power the wheels – but you are still walking behind it. These cost many $1000s so really only for professionals.

Let’s look at each below.

Cub Cadet Pro Z

This is THE zero turn by Cub Cadet people talk about when talking about the best zero turn for hills.

Take a look:

Ultimate zero turn hill mower

It’s a beast.

Check it out in action in this video:

You will pay for it though. It is likely out of reach for most but the largest of lawn care companies costing nearly $20k.

But for the money it has everything you need to conquer 25° slopes with ease. It has dual rear wheels for extra traction and stability. Weighted front wheels to move the centre gravity further from the Kawasaki engine. It has heaps more check it out in full at the link below.

Push Mower

Honda HRX or HRN Self-propelled Gas Lawn Mower

Honda HRX 217 Gas Lawn Mower

We currently have 2xHRNs and 1xHRX stored in the garage under lawn mower covers that we love to use all the time.

They are the best residential mowers on the market – hands down.

These push mowers are great on hills because they are light and have a very low risk of tipping over and hurting you.

See HRX here…

See HRN here…

Hydrostatic Walk Behind Mower

Wright Velke HC Commercial Mower

Wright Velke HC Hyrdostatic Walk Behind Commercial Mower

These commercial walk behind mowers uses a hydraulic system to power the wheels as you walk behind.

They have big tires and a wide base making them the best for hills – hands down.

Unfortunately they are expensive as you could probably guess from what they look like. You could save money by buying a used one though.

Still: A great hydro walk behind needs to be in the arsenal of every serious lawn care company.

Sources:

  1. Snapper Zero-Turn Mowers Operator’s Manual. MowersDirect.com. Info retrieved Sept 9, 2022.
  2. Diagonal Slope Mowing Woes!!! LawnSite.com. Info retrieved Sept 9, 2022.
  3. John Deere Tractors 100 Series Operator’s Manual. Lowes.com.