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The SelectTech 840 kettlebell is the standout — 4.8 across nearly 8,000 owners and our top pick in the adjustable kettlebell roundup. The current Results Series dumbbells carry the dial forward with a smaller record so far. Buy SelectTech for the fastest weight changes in home fitness; buy elsewhere if you drop weights, train in a garage that swings between temperatures, or want steel over composite.
How These Picks Were Chosen
Brand reviews get the same rules as everything else: the 4.3-star floor applies, listings are verified live, and duplicate color and configuration ASINs are matched by review count so one listing per product is carded. Both products here also appear in category roundups on this site — the 840 as our top adjustable kettlebell — and we disclose that rather than inventing separate winners. The comparison standard throughout is our own adjustable dumbbell roundup: SelectTech has to justify itself against machines we already recommend, or this page would say so.
1. The Standout: BowFlex SelectTech 840 Adjustable Kettlebell
BowFlex SelectTech 840 Adjustable Kettlebell
BowFlex · 4.8★ from 7,697 verified ratings
- 4.8 across nearly 8,000 owners — SelectTech’s best record
- Six settings from one dial, secure under swings
- Replaces a rack of cast bells in one footprint
- Also our Best Overall in the adjustable kettlebell roundup
Why we picked it: If SelectTech has a masterpiece, this is it. Kettlebells are the hardest test of an adjustable mechanism — swung, inverted, caught — and the 840’s dial passes it across a base of nearly eight thousand owners at 4.8, which no rival in that category approaches. We card it here and in our kettlebell roundup, openly, because it is genuinely the same recommendation rather than two manufactured ones. Trade-offs: the body is wider and squarer than a cast bell in the rack position, and the top setting will feel light to strong swingers eventually.
2. The Current Dumbbells: BowFlex Results Series SelectTech Dumbbells
BowFlex Results Series SelectTech Dumbbells
BowFlex · 4.6★ from 210 verified ratings
- The dial system in BowFlex’s current dumbbell line
- One-motion weight changes — still the fastest in home fitness
- Replaces a full dumbbell rack in a corner of a room
- 210-owner base so far — younger than the classic listings
Why we picked it: The Results Series carries the SelectTech idea forward: spin the dial, lift, train — the change takes seconds, which matters more than any spec when you are running drop sets or supersets at home. Early owners rate it well. The honest framing: 210 reviews is a young record for a product line whose reputation was built on much older listings, and the trade-offs of the format are unchanged — composite shells, a longer overall length than fixed dumbbells, and the dial mechanism’s well-known dislike of being dropped.
Side-by-Side Comparison
| Product | Line | Best for | Mechanism | Owner record | See price | |
|---|---|---|---|---|---|---|
| The Standout | BowFlex | 840 kettlebell | Swings, goblet work, presses | 6 settings | 7,697 owners at 4.8 | Check price |
| The Current Dumbbells | BowFlex | Results Series pair | Fast changes, small spaces | Dial system | 210 owners at 4.6 | Check price |
Buying Considerations
The dial's strength is speed; its weakness is drops. SelectTech changes weight faster than any competing system — that is the product. The consistent owner complaint across two decades is what happens when the weights are dropped or racked carelessly: selector pins and plastic shells are the parts that break, and they are not user-serviceable in most cases. If you train hard enough to drop dumbbells, buy steel.
Length and shape are the other honest trade. Adjustable dumbbells are longer than fixed pairs at the same weight, which shows up in narrow-grip presses and can catch on the torso in some movements. Kettlebell versions are wider in the rack position. Neither is disqualifying; both are worth knowing before your first session rather than during it.
Temperature and humidity matter more than people expect. Composite shells and dial mechanisms live happier indoors than in an unheated garage that swings from freezing to humid. Our garage gym planning guide covers the climate problem generally — if your gym is a garage, that argues for steel plates and cast bells over any adjustable system.
Compare against the alternatives honestly. Our adjustable dumbbell roundup carries the direct rivals — including a steel-plate system with a far deeper record. SelectTech wins on change speed and the kettlebell; rivals win on durability under abuse. Both pages exist so you can pick by which trade suits your training, and we earn either way.
So Which One Should You Buy?
Adjustable kettlebell buyers: the SelectTech 840. The best record in its category — and the same pick as our roundup.
Fast weight changes in a small space: the Results Series dumbbells. The dial at its fastest — young record, and don’t drop them.
Ready to buy?
Jump straight to our picks on Amazon — check the current price at click-through.
FAQ
Are BowFlex SelectTech dumbbells worth it?
For home training in a climate-controlled room where speed between sets matters, yes — nothing changes weight faster. For garage gyms, dropped sets, or anyone who wants equipment that tolerates abuse, the steel-plate systems in our adjustable dumbbell roundup are the better buy, and we say so there too.
What breaks on SelectTech weights?
The consistent owner-reported failure is the selection mechanism after drops or rough racking — dials that stop indexing, or shells that crack. Used gently they last for years; used like commercial gym dumbbells they do not. Racking them on the supplied trays rather than the floor is the single best habit.
SelectTech 552 vs the current Results Series — which should I buy?
The lineup has been revised repeatedly, and older model listings come and go on Amazon. The practical answer is to buy the current listing with a real owner record rather than chasing a discontinued model number — and to verify what is in the box, since bundles vary by listing.
Is the 840 kettlebell better than cast bells?
For space and range, clearly — it replaces six bells. For feel in the rack position and indifference to being dropped, cast bells still win. Many home gyms end up with the 840 for variety plus one heavy cast bell for swings, which our kettlebell roundup covers.
Related Guides
How We Research
Picks are researched and written by Mike Callahan based on manufacturer specifications, current Amazon listings, and patterns across verified owner reviews — particularly the negative ones. We are not a testing lab and do not claim to be; our full standard is in the editorial policy. Specifications and included accessories vary by listing, so confirm current details at the retailer before buying.
Note: The SelectTech 840 is carded both here and in our adjustable kettlebell roundup under this site’s brand-guide exception, disclosed in both places and enforced by an explicit verifier allowlist. BowFlex revises this lineup frequently and older model listings appear and disappear — confirm the current listing contents before buying. Ratings verified on the live listings August 6, 2026.