Adjustable Kettlebell: Is One Worth Buying? Types, Pros and Cons

An adjustable kettlebell is worth buying if you train at home, don't have room for a row of bells, and spend most of your time on goblet squats, deadlifts, rows and two-handed swings. If your training leans towards snatches, cleans and Turkish get-ups, buy two or three fixed cast-iron bells instead, because the shape and feel matter far more for those lifts than the convenience of one bell.

That's the short version. The longer one depends on which kind of adjustable bell you're looking at, since the designs differ a lot more than the product photos suggest.

The three main designs

Dial or selector kettlebells

These work like selector dumbbells: the bell sits in a cradle surrounded by plates, you turn a dial, and the handle lifts out with only the plates you've picked. The BowFlex SelectTech 840 is the best-known example, and it's the same idea as the selector systems we covered in our PowerBlock Elite EXP review, applied to a single bell.

You change weight in a couple of seconds, which suits circuits and supersets. The trade-off is bulk: the body has to house the selector, so it's boxier than a cast-iron bell at the same weight, and there's plastic in the mechanism that you really don't want to drop on a hard floor.

Plate-loaded handle bells

Here you get a handle with a central post or base, plus loose cast-iron plates that stack onto it and lock in place. The Yes4All model below, for instance, starts with a 3.5kg base handle and adds six plates to reach 18kg. Changing weight takes a minute or so rather than seconds, but there's less to break, and these are usually much cheaper.

Internally loaded shells

This is the newest style in the UK and arguably the most "kettlebell-like". A hollow steel shell, usually in competition shape, takes small plates inside the base, which you bolt in with a hex key. Because the outer shell never changes, the handle and body feel identical at every weight. It's the slowest to adjust and the range is narrower, but if you care how the bell moves, this is the design to look at.

Weight ranges and the gaps between settings

The jumps matter more than the headline range. A bell that goes "3.5kg to 18kg" sounds flexible, but look at the actual steps. The BowFlex SelectTech 840 offers 3.5kg, 5.5kg, 9kg, 11kg, 16kg and 18kg, so the jump from 11kg to 16kg is a 5kg leap at exactly the point where many people are trying to progress their swings. Smaller jumps either side don't fix that gap.

Compare that with the Bells of Steel shell, which runs from 12kg to 20.5kg in 0.5kg and 1kg steps across 18 settings. You can't go light with it, but you'll never be stuck between two weights.

Before you buy, write down which weights you actually use for your main lifts. If your goblet squat is at 14kg and your press is at 10kg, check that the bell has settings near both. A clean range on paper can still leave a hole in the middle.

How they handle swings, snatches and get-ups

This is where adjustable kettlebells earn their mixed reputation, and it comes down to four things.

Handle shape. A good cast-iron bell has a round handle with a smooth window you can slide your hand through. Dial bells often use a wider, moulded handle that's fine for two hands but can feel awkward when you switch hands mid-swing. Competition-style shells, by contrast, keep a fixed 35mm handle (on the Bells of Steel model) at every setting.

Body bulk and the rack position. On a kettlebell snatch or a clean, the bell rolls over your wrist and rests on your forearm. A compact round bell sits there comfortably; a tall, flat-sided dial bell tends to dig into your forearm and sit further from your body. That's the biggest single reason experienced kettlebell users avoid selector designs for ballistic one-arm work.

Rattle and play. Anything built from multiple parts can shift slightly. On a slow deadlift you'll never notice. During a kettlebell swing, a small knock at the top of every rep gets old fast, and dial bells with plastic housings are the usual offenders. Bolted plate systems are generally quieter.

Turkish get-ups. You hold the bell overhead for the whole movement, so balance and wrist position count for more than anything else. A compact bell with a centred load is easier to control here, which again favours cast iron or competition shells over chunky selector bells.

None of that makes adjustable bells unsafe for these lifts. It makes them less pleasant, and that's a real cost if they're your main lifts.

Cost per kg against buying fixed bells

Fixed cast-iron kettlebells aren't expensive in the UK. At the time of writing, a basic 8kg cast-iron bell sells for around £20 to £28 on Amazon, and a 16kg one for around £32 to £50. A sensible starter trio of 8kg, 12kg and 16kg should therefore land somewhere around £80 to £120.

Set that against the adjustable options below:

Model	Range	Price (at the time of writing)	Settings
BowFlex SelectTech 840	3.5kg to 18kg	around £199	6
Bells of Steel internally loaded shell	12kg to 20.5kg	around £160	18
Yes4All JX7N plate-loaded	3.5kg to 18kg	around £95	Base handle plus 3 pairs of plates

The BowFlex costs about as much as three or four fixed bells, so you're paying for the space saving and the quick change, not for value. The Yes4All undercuts a fixed trio. The Bells of Steel sits in between but replaces a run of heavier bells (12kg, 16kg and 20kg fixed bells cost noticeably more than light ones), so it makes the most financial sense once you're past the beginner weights.

One thing adjustables can't do is give you two bells at once. Double-kettlebell front squats or presses need a pair, and that's when fixed bells win easily. The same trade-off applies to dumbbells, and we go into it in more detail in are adjustable dumbbells worth it.

What to look for

• The full list of settings, not just the minimum and maximum. Look for gaps of 4kg or more in the range you'll actually use.
• The locking mechanism. Metal pins, bolts and threaded collars beat plastic clips for anything you swing.
• Handle diameter and finish. Around 33mm to 35mm suits most hands for one-arm work; a powder-coated or lightly textured finish holds chalk and sweat better than glossy paint.
• A flat base, so the bell stands upright for renegade rows and doesn't roll when you set it down.
• Overall dimensions. A bell that's tall and wide at 9kg will feel clumsy for overhead work even though the weight is light.

For what it's worth, the research on kettlebells is thinner than the marketing suggests. A 2019 scoping review of 99 publications found effect sizes that were mostly trivial to small and called the evidence quality low (Meigh et al., BMC Sports Science, Medicine and Rehabilitation). A more recent narrative review still points to gains in strength, power and conditioning from kettlebell work (Cureus, 2024). Either way, the benefits come from training consistently, not from the specific bell, so buy whichever design you'll pick up three times a week.

If you buy one

These three cover the main designs and were in stock on Amazon UK when we checked. We haven't tested them in person; the notes below come from the listings and manufacturer specs.

BowFlex SelectTech 840 is the pick if fast changes matter most, for circuits or for a household where two people use different weights. Six settings from 3.5kg to 18kg, with that 11kg to 16kg gap to keep in mind.

Check the BowFlex SelectTech 840 price on Amazonaround £199

Bells of Steel internally loaded kettlebell suits anyone who already swings 12kg or more and wants a bell that feels like a proper competition kettlebell. The listing says it adjusts from 12kg to 20.5kg in 18 steps, using a 12kg steel shell plus 3kg, 2kg, 1kg and 0.5kg plates that bolt inside, so each change takes under a minute.

Check the Bells of Steel adjustable kettlebell on Amazonaround £160

Yes4All JX7N is the budget plate-loaded choice: a 3.5kg base handle and six cast-iron plates up to 18kg, a powder-coated finish and a flat bottom. It's a sensible first bell for someone who'll mostly squat, deadlift and do two-handed swings.

Check the Yes4All adjustable kettlebell on Amazonaround £95

If you'd rather go the fixed route, our best kettlebells UK guide covers cast iron and vinyl options, and the home gym hub has the rest of our kit guides.

Recommended reads

• Best kettlebells UK
• How to do a kettlebell swing
• Kettlebell snatch technique
• Are adjustable dumbbells worth it?
• PowerBlock Elite EXP review