10 Best Self Propelled Lawn Mower for Hilly Yards (July 2026) Buying Guide

Mowing a hilly yard can be one of the most physically demanding lawn care tasks you will face. After testing over a dozen self-propelled mowers on various slope grades, our team found that the right mower makes all the difference between an exhausting ordeal and a manageable task. Choosing the best self propelled lawn mower for hilly yards means looking for features like rear-wheel or all-wheel drive for traction, variable speed control for precise handling, and enough power to maintain cutting performance even on steep inclines.

If you have ever struggled with a mower that lost traction going uphill or felt like it was pulling you downhill, you understand why choosing the right self-propelled model matters. The wrong mower does not just make the job harder. It can also be dangerous on slopes where control is essential. Whether you are dealing with gentle rolling terrain or steeper sections of your property, this guide will help you find a mower that handles hills with confidence.

In this comprehensive guide, we have reviewed 10 top-rated self-propelled mowers specifically for hill performance. We tested traction on wet grass, ease of control on descents, and power delivery on inclines. You will also find our detailed buying guide covering drive systems, power sources, and safety considerations that matter most for hilly terrain. If you want a broader look at options for challenging landscapes, check out our guide to the best mowers for hills which includes riding mowers and zero-turn options.

Top 3 Best Self Propelled Lawn Mower for Hilly Yards (July 2026)

Quick Overview: 10 Best Self Propelled Lawn Mower for Hilly Yards (July 2026)

1. Greenworks 80V 21 Self-Propelled Cordless Mower – Best Overall

After three months of testing the Greenworks 80V on my property which includes a 15-degree slope section, I can confidently say this mower handles hills better than any battery-powered model I have used, making it a strong contender for the best self propelled lawn mower for hilly yards. The rear-wheel drive system with variable speed control gives you precise traction exactly when you need it. Going uphill, I never experienced the wheel spin that plagued front-wheel drive mowers I tested previously.

The 80V brushless motor delivers serious torque. When I hit a patch of thick fescue on an incline, the mower powered through without bogging down. The variable speed control lets you match your pace to the terrain. I found myself slowing down on steeper sections and picking up speed on flatter areas. This flexibility makes a huge difference when you are navigating varying terrain.

Battery performance impressed me. On my half-acre property with about 40% sloped terrain, I consistently finished with 15-20% battery remaining. The 4.0Ah battery charges in under an hour, so even if you have a larger property, a second battery would keep you mowing without much downtime. The LED headlights came in handy more often than I expected, especially during spring when I mowed earlier in the morning to beat the heat.

The 4-in-1 system handles mulching, bagging, side discharge, and turbo leaf pickup. I primarily used the mulching mode and found the clippings were finely chopped and distributed evenly. The 21-inch steel deck feels solid and shows no signs of wear after months of use. Being part of the Greenworks 80V ecosystem means you can share batteries with trimmers, blowers, and other tools, which adds significant value.

Who Should Buy This Mower

This mower is ideal for homeowners with small to medium yards (up to 1/2 acre) that include moderate slopes. The combination of power, traction control, and battery runtime makes it perfect for properties where gas mower noise would disturb neighbors. If you already own Greenworks 80V tools, the shared battery ecosystem makes this an even smarter choice.

Who Should Avoid This Mower

If your property exceeds 3/4 acre or includes very steep sections (over 20 degrees), you might want to consider a gas model or a riding mower. The 75-pound weight takes some adjustment on slopes, particularly when you need to turn around at the end of a pass. Also, if you frequently let your grass get very tall before mowing, battery life will be significantly reduced.

2. SENIX 22-Inch Self-Propelled Gas Mower with B&S Engine – Best Value

The SENIX 22-inch mower with the Briggs & Stratton EX625 engine delivers exactly what hilly yard owners need: reliable power and rear-wheel drive traction at a reasonable price. During my testing on a neighbor’s sloped property, this mower started on the first pull every single time. The 150cc engine provides steady, consistent power that does not fade when climbing inclines.

What surprised me most about this mower was how well the single-speed rear-wheel drive performed on hills. While variable speed systems offer more control, the fixed speed on the SENIX matched a comfortable walking pace for most slope conditions. The 11-inch rear wheels provide excellent traction, and I never felt the mower struggling to maintain grip on grass that ranged from slightly damp to dry.

The 22-inch cutting width covers more ground per pass than the typical 21-inch deck. This extra inch adds up over a larger property. The 3-in-1 system handles mulching, bagging, and side discharge with equal competence. I tested all three modes and found the transitions straightforward. The 19-gallon collection bag holds a substantial amount of clippings, reducing trips to empty it.

At 54 pounds (shipping weight), this is one of the lighter self-propelled gas mowers available. The reduced weight becomes apparent when you need to turn around on a slope or maneuver around obstacles. Assembly requires no tools and took me about 10 minutes from box to first start. The steel deck construction feels durable and should provide years of reliable service.

Who Should Buy This Mower

This SENIX is perfect for homeowners who want gas power reliability without the premium price tag. If your property has moderate hills (up to 15 degrees) and ranges from 1/4 to 1/2 acre, this mower hits the sweet spot of performance and value. The Briggs & Stratton engine gives you confidence that parts and service will be available for years to come.

Who Should Avoid This Mower

If you prefer the quiet operation of battery mowers or live in an area with noise restrictions, the gas engine may be a drawback. Some users reported quality control issues with shipping damage or carburetor problems from factory testing residue, so inspecting the unit upon arrival is important. The single-speed drive system limits your ability to slow down on very steep sections.

3. Greenworks 40V 21 Self-Propelled Cordless Mower – Budget Pick

The Greenworks 40V self-propelled mower holds the number one best-seller spot in walk-behind mowers for good reason. With over 19,000 reviews and a 4.2-star rating, this mower has proven itself to thousands of homeowners. I tested it on a property with rolling terrain and found it capable of handling moderate slopes effectively, especially considering its budget-friendly price point.

The 40V brushless motor runs significantly quieter than any gas mower I have used. You can actually hold a conversation while mowing, which is not something you can say about most gas models. The rear-wheel drive with variable speed gives you control on slopes, letting you slow down for inclines and pick up the pace on flat sections. This adaptability matters when your property has varied terrain.

Battery performance met expectations for normal mowing conditions. I completed about 1/3 acre on a single charge with some slope work included. The included 5.0Ah battery provides more runtime than smaller capacity options, and the fast charger gets you back to work quickly. Being part of the Greenworks 40V ecosystem means this battery works with over 75 other tools, adding real value if you plan to expand your cordless collection.

The 3-year warranty on both the tool and battery provides peace of mind that budget-priced products sometimes lack. The 4-in-1 system handles mulching, bagging, side discharge, and turbo leaf pickup. LED headlights allow for early morning or late evening mowing when temperatures are more comfortable. For the price, you get a lot of features that competitors reserve for higher-priced models.

Who Should Buy This Mower

This mower is ideal for budget-conscious homeowners with smaller properties (up to 1/3 acre) that include gentle to moderate slopes. If you want to transition from gas to battery power without spending a fortune, this Greenworks model offers excellent value. The extensive warranty and massive user base mean you can buy with confidence.

Who Should Avoid This Mower

If your property regularly has wet grass or you tend to let grass grow tall before mowing, the 40V motor may struggle more than higher-voltage options. Properties larger than 1/2 acre will likely require a second battery. Some users noted that bagging does not catch all clippings effectively, so if bagging is your primary mowing method, this may not be the best choice.

4. WORX Nitro 21 Cordless Mower with Aerodeck – Top Rated

The WORX Nitro 21 stands out for its innovative Aerodeck technology, which uses a vented design to boost air volume in the cutting deck. This prevents clogs and clumping that can slow you down on hills. During testing on a property with thick, slightly damp grass, I noticed the mower continued cutting smoothly while other models would have bogged down or clogged.

The Intellicut technology automatically adjusts power based on grass thickness. When I hit a patch of thicker growth on an incline, the mower dialed up the cutting speed without any input from me. On thinner sections, it conserved battery by reducing power. This smart feature extends runtime and ensures consistent cutting quality across varying conditions.

Having two 5.0Ah batteries included means you get about 50 minutes of combined runtime. The variable speed self-propulsion reaches up to 3.7 MPH, which covers a comfortable walking pace for most users. The 7-position cutting height adjustment (1.5 to 4 inches) gives you flexibility for different grass types and conditions. The fully collapsible handle allows for vertical storage, saving garage space.

The 5-year warranty is among the best in the category and reflects WORX confidence in their Brushless Motor 2.0 technology. This motor delivers 40% more power and 10% longer runtime than previous generation brushless motors. The WORX PowerShare platform includes over 140 tools, so your batteries work across a wide range of equipment from lawn care to home improvement tools.

Who Should Buy This Mower

This WORX Nitro is perfect for homeowners with properties up to 1/2 acre who want smart technology that adapts to mowing conditions. If you deal with varying grass thickness or occasional damp conditions, the Aerodeck and Intellicut features will serve you well. The generous 5-year warranty makes this a low-risk investment.

Who Should Avoid This Mower

If your property has significant edging or landscaping where the metal deck might make contact, you will need to be careful to avoid scraping. Some users found battery life shorter than the advertised 50 minutes, especially in challenging conditions. The proprietary safety key is essential for operation, so losing it would render the mower unusable until a replacement arrives.

5. BILT HARD 21 Self-Propelled Gas Lawn Mower

The BILT HARD 21-inch self-propelled mower offers serious power at an affordable price point. The 201cc OHV engine produces 9.0 ft-lb of torque, which is more than most competitors in this price range. When I tested it on a property with overgrown sections and some slope, the mower handled both tall grass and inclines without complaint.

The no-choke, no-primer design simplifies starting significantly. In my testing, the engine started within 2-3 pulls every time. This straightforward starting process is particularly valuable if multiple family members will use the mower. The rear-wheel drive provides good traction on inclines, pulling the mower uphill rather than relying on you to push.

The 8-position cutting height adjustment offers more flexibility than many competitors that only offer 6 positions. You can adjust from 1.2 inches to 3.75 inches using a single lever that synchronizes all four wheels. The 3-in-1 steel deck handles mulching, side discharge, and rear bagging. I found the mulching performance particularly good, producing fine clippings that disappeared into the lawn.

At 79 pounds, this mower is on the heavier side, which provides stability on slopes but can make turnarounds at the end of passes more effort. The foam-wrapped handle provides a comfortable grip, and the compact foldable design helps with storage in smaller spaces. Assembly is straightforward, and the mower arrives mostly ready to go.

Who Should Buy This Mower

This BILT HARD model is ideal for homeowners who want gas power and plenty of torque without spending a lot. If your property has overgrown areas or you occasionally let grass get taller than ideal, the 201cc engine will handle it. The affordable price makes this accessible for budget-conscious buyers who still want self-propelled functionality.

Who Should Avoid This Mower

If you have significant physical limitations or struggle with heavier equipment, the 79-pound weight combined with wheels that do not disengage from drive mode may make maneuvering difficult. Some users reported height adjustment slipping during use, requiring occasional re-adjustment. Quality control varies, so inspecting the unit upon arrival is recommended.

6. SENIX 21 Self-Propelled Gas Mower with 170cc Engine

The SENIX 21-inch self-propelled mower offers a compelling combination of lightweight design and reliable power. At just 61.7 pounds, this is one of the lightest self-propelled gas mowers available, which makes a noticeable difference when navigating slopes and making turnarounds. The 170cc OHV engine produces 3.8 HP and starts reliably with minimal effort.

During testing on a moderately sloped property, I appreciated how easy this mower was to control. The lighter weight did not seem to compromise hill performance, as the self-propelled system provided adequate traction on inclines. The Vortex tunnel design helps reduce grass buildup under the deck, which keeps cutting performance consistent even in damp conditions.

The 6-position height adjustment ranges from 1.25 inches to 3.75 inches, giving you good flexibility for different grass types. The 3-in-1 system handles mulching, side discharge, and rear bagging, with the 1.7-bushel grass bagger collecting clippings effectively. The mower arrives with engine oil included, so you can start mowing almost immediately after unboxing.

The 8-inch front wheels and 11-inch rear wheels provide good maneuverability across varied terrain. The larger rear wheels help with traction on slopes and make the mower easier to turn. The pre-filled oil and straightforward setup process means most users can be mowing within 15 minutes of opening the box.

Who Should Buy This Mower

This SENIX model is perfect for homeowners with smaller properties (up to 0.4 acres) that include moderate slopes. If you prefer a lighter mower that is easier to maneuver and store, the 61.7-pound weight is a significant advantage. The included accessories and pre-filled oil make this ready to use right out of the box.

Who Should Avoid This Mower

If your property exceeds 0.4 acres or includes very steep sections requiring extended hill climbing, you may want a more powerful option. The 170cc engine handles normal conditions well but can struggle with very tall or wet grass. The limited review count compared to more established models means long-term reliability data is still developing.

7. AMERISUN 21 Self-Propelled Gas Mower with RWD

The AMERISUN 21-inch self-propelled mower delivers impressive value with its 170cc OHV engine and rear-wheel drive system. The auto choke system makes starting straightforward, and the reinforced steel deck provides durability for regular use. During my evaluation, the mower started easily and maintained consistent power on slopes.

The rear-wheel drive system is specifically designed for traction on flat or inclined conditions. This makes the mower feel like it pulls itself uphill rather than requiring you to push. The 21-inch heavy-duty blade produces fine cuts and small clippings, which works well for mulching or bagging applications.

One feature I appreciated was the fully assembled delivery. The mower arrives ready to use after simply unfolding the handle. This saves the frustration of assembly that many competitors require. The single-lever 6-position height adjustment makes changing cutting heights quick and easy, ranging from 1.5 inches to 3.9 inches.

The folding handle allows for space-saving storage, which matters if garage space is limited. At 66 pounds, this mower strikes a balance between stability on slopes and maneuverability during turnarounds. The 4-cycle OHV engine runs cleaner than 2-cycle alternatives and does not require mixing oil with gas.

Who Should Buy This Mower

This AMERISUN model is ideal for budget-conscious homeowners who want reliable gas power with good hill traction. If you prefer a mower that arrives ready to use without assembly hassles, this delivers. The rear-wheel drive makes it suitable for properties with moderate slopes where front-wheel drive would struggle.

Who Should Avoid This Mower

If you prefer a slower walking pace, the self-propelled speed may feel too fast based on some user feedback. The mower is not Prime eligible, so shipping times may be longer than Amazon Prime products. The limited review count (39 reviews) means there is less long-term reliability data compared to more established brands.

8. YARDMAX 24-Inch Electric Start Self-Propelled Mower

The YARDMAX 24-inch self-propelled mower offers the convenience of electric start and a wider cutting deck for efficient mowing. The 201cc engine provides ample power, and the electric start eliminates the need for pull-cord starting, which is especially valuable for users with physical limitations. The CVT (Continuously Variable Transmission) offers 6-speed adjustment for matching your pace.

The 24-inch cutting width covers more ground per pass than standard 21-inch mowers, which reduces total mowing time on larger properties. The MAXFlow Deck Technology improves airflow for better mulching and cutting performance. During evaluation, the deck produced consistent cuts across varying grass heights.

The 7 cutting height options range from 1.57 inches to 3.74 inches, giving you flexibility for different lawn conditions. The double ball bearing wheels roll smoothly, and the high wheel design (with larger rear wheels) helps with maneuverability. The deck cleanout port makes maintenance easier by allowing you to clear debris from under the deck.

At 103.5 pounds, this is the heaviest mower in our review, which provides stability on hills but makes maneuvering more challenging. The 16-gauge stamped steel deck is built for durability and should withstand years of regular use. The one-piece seamless deck design reduces vibration for a more comfortable mowing experience.

Who Should Buy This Mower

This YARDMAX is ideal for homeowners with larger properties (1/2 acre or more) who want the efficiency of a 24-inch deck. The electric start is perfect for those who struggle with pull-cord starting. The wide deck significantly reduces mowing time compared to narrower options.

Who Should Avoid This Mower

If you have physical limitations or prefer lighter equipment, the 103.5-pound weight will be challenging, especially on slopes. Some users noted the speed control does not offer the fine adjustment expected from a 6-speed system. If you regularly let grass grow tall before mowing, the engine may struggle when grass exceeds the deck height.

9. YARDMAX 22-Inch Self-Propelled Gas Mower with CVT

The YARDMAX 22-inch self-propelled mower has earned a strong following with over 1,500 reviews and features designed specifically for challenging terrain, making it a strong contender for the best self propelled lawn mower for hilly yards. The aggressive spike tread pattern on the rubber tires provides excellent traction on hills and uneven ground. The CVT transmission with 6-speed lever lets you adjust pace to match conditions.

The MaxFlow deck technology with its volute spiral design improves airflow and cutting efficiency. The 16-gauge stamped steel deck is built heavy-duty and the one-piece seamless construction reduces vibration. During testing on varied terrain, the deck produced consistent cutting results.

The 7 cutting heights range from 1.38 inches to 3.55 inches, accessible via a single-lever adjustment. Double ball bearing wheels ensure smooth rolling even after extended use. The deck cleanout port makes it easy to clear grass buildup from under the deck. The folding handle allows for compact storage.

At 84.2 pounds, this mower is on the heavier side, which provides stability but can make turnarounds on slopes more effort. Users consistently praised the cutting performance and build quality, though some noted the minimum speed is faster than expected. The aggressive tire tread does improve hill traction significantly.

Who Should Buy This Mower

This YARDMAX is ideal for homeowners who prioritize build quality and cutting performance. If your property has hills or uneven terrain where traction matters, the aggressive tire tread delivers. The CVT transmission offers more speed options than fixed-speed alternatives.

Who Should Avoid This Mower

As of this writing, this model is currently unavailable, so you may need to wait for restocking or consider alternatives. If you prefer a slower walking pace, the minimum speed may feel too fast. The heavier weight (84.2 pounds) combined with wheels that do not disengage makes manual pushing difficult when needed.

10. PowerSmart 21-Inch 3-in-1 Push Lawn Mower

The PowerSmart 21-inch push mower represents the most affordable option in our roundup. While it is not self-propelled, I included it because many readers ask about budget options for hilly yards. The 144cc OHV engine provides adequate power for normal mowing conditions, and the 62-pound weight makes it easier to push uphill than heavier alternatives.

During testing on a modest slope, I found this mower manageable for fit users. The lightweight design becomes an advantage when you need to turn around or maneuver around obstacles. The engine started on the first pull consistently in my testing, which speaks to the quality of the OHV engine design.

The 3-in-1 cutting system handles mulching, bagging, and side discharge. The 6-position height adjustment ranges from 1.5 inches to 3.9 inches. The 7-inch high wheels help with maneuverability on uneven terrain. For small properties with gentle slopes, this push mower can get the job done without the expense of self-propelled alternatives.

At $249.98, this mower offers excellent value for budget-conscious homeowners. The compact design works well for tight spaces and smaller yards. Fuel efficiency is good, and the included bottle of oil means you can start mowing immediately after setup.

Who Should Buy This Mower

This PowerSmart is ideal for homeowners with small yards (under 1/4 acre) and gentle slopes who want the most affordable option. If you are physically fit and do not mind pushing, this mower delivers reliable performance at a fraction of the cost of self-propelled models. It is also good for tight spaces where larger mowers would not fit.

Who Should Avoid This Mower

If your property has significant slopes or you have physical limitations, the lack of self-propulsion will make mowing much more difficult. This is not suitable for yards over 1/4 acre or properties with challenging terrain. Some users reported concerns about plastic components, so long-term durability may be a consideration.

Buying Guide: Choosing the Best Self-Propelled Mower for Hilly Yards

Finding the right self-propelled mower for hills requires understanding several key factors that directly impact performance on slopes. After testing numerous mowers and researching user experiences from forums like r/lawncare and r/lawnmowers, I have identified the critical elements that separate hill-capable mowers from those that struggle on inclines.

Drive System: FWD vs RWD vs AWD for Hills

The drive system is perhaps the most important factor for hill performance. Front-wheel drive (FWD) mowers are generally not recommended for slopes because weight shifts to the rear wheels when going uphill, reducing traction on the driven front wheels. This causes wheel spin and loss of control.

Rear-wheel drive (RWD) is the preferred choice for hilly terrain. When climbing a slope, your body weight and the natural weight distribution push down on the rear wheels where the traction is. This keeps the drive wheels gripping even on inclines. Every mower in our top recommendations features RWD or equivalent traction systems.

All-wheel drive (AWD) mowers offer the best traction but are less common in residential models and typically cost more. For most homeowners with moderate slopes (up to 15 degrees), RWD provides adequate traction without the additional cost and complexity of AWD systems.

Gas vs Battery Power for Hills

Both power sources have merit for hill mowing, and the best choice depends on your specific situation. Gas mowers provide consistent power regardless of slope or grass conditions. You do not have to worry about battery drain from hill climbing. However, they are louder, require more maintenance, and need fuel storage.

Battery mowers have improved dramatically in recent years. Higher voltage systems like the 80V Greenworks deliver torque comparable to gas. They are quieter, start instantly, and require minimal maintenance. For hills, look for higher voltage (40V minimum, 80V preferred) and brushless motors that provide consistent torque output. For more battery options, check our guide to the best cordless lawn mowers.

Forum users consistently mention that battery life decreases significantly on hills, so size your battery capacity accordingly. If your property is over 1/2 acre with significant slopes, consider having a second battery or opting for gas.

Wheel Size and Tire Design

Wheel size and tire design directly impact traction on slopes. Larger rear wheels (11 inches or more) provide better grip and roll more smoothly over uneven terrain. The YARDMAX models in our review feature aggressive spike tread patterns specifically designed for hill traction.

Look for mowers with rear wheels at least 10-11 inches in diameter. The larger contact patch improves grip on slopes, especially when grass is slightly damp. Smooth tires may look cleaner but offer less traction than textured tread patterns.

Variable Speed Control

Variable speed control allows you to match the mower pace to terrain conditions. On steeper sections, you can slow down for better control. On flatter areas, you can speed up to finish faster. Single-speed mowers are simpler but may feel too fast on steep sections or too slow on flat areas.

The CVT (Continuously Variable Transmission) systems in YARDMAX mowers offer the most precise speed adjustment, while the simple variable speed levers on Greenworks and WORX models provide adequate control for most users.

Weight Considerations

Weight is a double-edged sword for hill mowing. Heavier mowers provide more stability and traction on slopes, but they are harder to turn around at the end of a pass and more difficult to control when going downhill. Finding the right balance matters.

For most users, mowers in the 60-80 pound range offer the best compromise. Light enough to maneuver but heavy enough to maintain traction. If you have physical limitations, prioritize lighter models. If your slopes are particularly challenging, the extra weight of larger gas mowers may be worth the trade-off.

Safety Features for Slope Mowing

Safety on slopes cannot be overstated. Look for mowers with blade brake clutches that stop the blade without shutting off the engine, allowing you to safely traverse non-grass areas. Dead man controls that stop the mower when you release the handle are standard on self-propelled models and essential for safety.

Forum discussions emphasize mowing across slopes rather than up and down when possible. This provides better footing and reduces the risk of the mower sliding or tipping. Never mow slopes greater than 15 degrees with a walk-behind mower, and consider a riding mower or robotic mower for steeper terrain.

For larger properties with significant slopes, you may want to explore our guides to best riding lawn mowers and best zero turn mowers for hills for alternatives better suited to extreme terrain.

Cutting Width and Property Size

Match cutting width to your property size. Standard 21-inch decks work well for most residential properties. The 22-inch and 24-inch options in our review can save time on larger properties but may be harder to maneuver in tight spaces. For properties under 1/4 acre, a 21-inch deck is sufficient.

The wider decks on the SENIX 22-inch and YARDMAX 24-inch models reduce the number of passes needed, which adds up over larger properties. However, wider mowers are heavier and may be harder to turn on slopes.

Frequently Asked Questions

Conclusion: Our Top Recommendations for 2026

After extensive testing and research, our top pick for the best self propelled lawn mower for hilly yards remains the Greenworks 80V 21-inch model. Its combination of powerful brushless motor, rear-wheel drive with variable speed, and excellent battery performance makes it the most capable battery-powered option for slopes. The quiet operation and extensive 75+ tool ecosystem add significant value.

For homeowners who prefer gas power and want the best value, the SENIX 22-inch with Briggs & Stratton EX625 engine delivers reliable performance at a reasonable price. The proven engine and rear-wheel drive system handle moderate hills with confidence, and the 22-inch deck covers ground efficiently.

Budget-conscious buyers should strongly consider the Greenworks 40V 21-inch model. With over 19,000 reviews and best-seller status, this mower has proven itself to thousands of homeowners. The 3-year warranty on both tool and battery provides peace of mind at an accessible price point.

Whatever mower you choose, remember that proper technique matters on hills. Mow across slopes when possible, maintain a pace that keeps you in control, and never mow slopes that exceed the manufacturer’s recommendations. For a wider selection of options including riding mowers and zero-turn models, browse our complete guide to the best self-propelled lawn mowers.