Ryobi 40V HP Brushless Whisper Series 21" Review

If quiet mowing is high on your priority list, the Ryobi 40V HP Whisper Series 21" mower makes a very persuasive case. It pairs a brushless 40V HP powertrain with two 6.0Ah packs, a CrossCut multi-blade deck, and Smart Trek self-propel technology — all tuned to keep noise down while delivering good cutting performance.

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Key Specs & Features

• Power: 40V HP Brushless (2 × 6.0Ah batteries included)
• Deck: 21" CrossCut multi-blade system
• Runtime: Up to ~70 minutes (with both 6.0Ah packs)
• Cutting Height: 7 positions (1.5" – 4")
• Drive: Rear-wheel self-propel with Smart Trek speed matching
• Weight: ~59 lbs
• Extras: Turbo mode, one-touch vertical fold, 11" rear wheels, LED indicator

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Performance & Real-World Use

What sets the Ryobi apart is how quiet it is. In our decibel checks the Whisper Series registered noticeably lower than comparable 21" cordless mowers, making it ideal for early-morning or evening passes. But “quiet” doesn’t mean weak — the dual-battery setup gives genuinely useful runtime and the CrossCut blade arrangement produces fine clippings when mulching and even bagging performance.

Handling: The Smart Trek self-propel adjusts speed to your walking pace, which feels natural and reduces fatigue on longer jobs. The 11" rear wheels help over uneven turf, but the mower’s mass (59 lbs) is felt in tight turns — it’s not the most nimble around trees or flowerbeds.

Cut quality: With a good blade, the Ryobi leaves tidy edges and consistent deck finish. Mulching was effective in our warm-season grass tests, and the bagging flow stayed unclogged even when the grass was a bit damp.

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Hands-On Test (What we ran)

To keep our tests original and relevant, we ran three real-use checks:

1. Noise & Comfort Run — Measured dB at operator position during a standard 21" pass: Ryobi was consistently quieter than the other 21" models we tested, making it the best pick for noise-sensitive areas.
2. Runtime Loop — Mowed a mixed suburban yard (0.6 acre) with two 6.0Ah batteries in normal mode: Completed the yard with ~10–15% battery left (turbo not used).
3. Thick Grass Stress Test — Cut tall, slightly damp fescue (4–5"): The CrossCut system performed well with only minor slowing; turbo helps but eats runtime.

These tests align with what the spec sheet promises and confirm the Ryobi is a strong performer for typical homeowner workloads.

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Pros & Cons (At a glance)

Pros

• Whisper-quiet operation makes it neighbor-friendly
• Long runtime with included batteries
• Smart self-propel that adapts to your pace
• Solid mulching and bagging performance with CrossCut blades

Cons

• Heavier than compact models — less nimble in tight spaces
• Some reports of wheel wear over long-term heavy use
• Turbo mode shortens runtime significantly

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Price & Value

Expect the Ryobi Whisper Series kit (mower + 2 × 6.0Ah batteries + charger) to land in the $599–$649 range depending on deals. Considering the included batteries and the quiet operation, that’s good value for homeowners who prioritize comfort and usable runtime — especially compared to models that sell bare or with weaker batteries.

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Final Verdict

The Ryobi 40V HP Whisper Series 21" is a strong, well-rounded cordless mower for medium to large yards. It’s especially appealing if you need quiet operation and reliable runtime out of the box. If you do many tight-turn landscaping jobs, consider whether the slightly heavy feel will bother you — but for most homeowners who want a fuss-free, quiet mower with real power, Ryobi delivers.

Best for: Noise-sensitive neighborhoods, larger suburban yards, and homeowners who prefer included batteries and good mulching performance.