I have coached strength in Denver for 12 years, and I have watched a lot of home gyms get built in garages, spare bedrooms, and one memorable converted chicken coop. The question I answer most often is not about barbells. It is about adjustable dumbbell sets: which pair covers the most training in the smallest footprint, and which ones give up when a grown adult grabs them for a set of rows. This comparison is the version of that answer I give when I am not being polite about it.
If you want the short answer, the BowFlex Results Series SelectTech is the adjustable set I would hand to a client who wants one purchase that lasts, and the 6-in-1 octagon set is the one I would hand to someone building a first garage gym on a tight budget. Everything below is the reasoning, not the marketing.
Adjustable dumbbell set, 20/35/45/55/70/90lbs Free Weights set with upgraded nut, 5 in 1 Weight Set Used as Kettlebells, Barbell, Push up Stand, Fitness Exercise for Home Gym Suitable Men/Women
The widest stated weight ladder of the budget four, with a nut-and-collar lock and conversions to kettlebell, barbell, and push-up stand
Nut-and-collar systems live or die on the thread, and five modes means five sets of parts to keep track of
6-in-1 Adjustable Dumbbell & Barbell Weight Set, 45LB Octagon Anti-Roll Iron Sand & Cement Composite Weights, All-in-One Home Gym Equipment with Kettlebell, Push-up Stands & Gloves
Cheapest route to a dumbbell, a barbell, and a kettlebell in one box, and the octagon heads will not roll away mid-set
A 45 pound ceiling, composite heads that feel bulky in the hand, and gloves that are packaging, not equipment
2026 FDB2 Updated Adjustable Dumbbell Set of 2, 5-in-1/10-in-1 Weights Dumbbell Set with Storage Box, 25lbs/55lbs Adjustable Weights with Anti-slip Silicone Grip, Weight Set For Home Gym Suit both Men and Women
Sold as a pair, arrives with a storage box, and the anti-slip silicone grip targets the exact place cheap adjustables fail
The 5-in-1 and 10-in-1 naming is confusing, and part of what you pay for is the box
BowFlex Results Series SelectTech Dumbbells
The dial mechanism the rest of this category is measured against, in a set that stays put on a stand and holds resale value
It sits in an entirely different price bracket, and you still want the stand
Prices and availability were captured from Amazon Creators API and may change.
How I judge an adjustable set
I have a short list, and it has not changed in a decade.
First, the mechanism. On a dial set, that means how the plates index and whether the selector survives chalk, sweat, and being set down hard. On a nut-and-collar set, it means the thread quality. A coarse, poorly cut thread loosens under vibration. You feel it as a click in the handle halfway through a set of presses, and that click is the beginning of the end.
Second, the plates. The weight plates should not wobble. If they wobble, the welds are lying to you. I do not care what the marketing copy says about composite materials or upgraded hardware. I care whether the stack is quiet at rep eight of a set of twelve.
Third, the handle. Knurling is the soul of a dumbbell. Too smooth and you are fighting grip on every pull. Too sharp and you are taping your palms by Wednesday. Silicone and rubber sleeves are a reasonable compromise for a home set, because they hold without shredding skin, but they collect dust and they get slick once your hands are sweaty. That is a real trade-off, not a dealbreaker.
Fourth, the footprint. Round heads roll. Hex heads stay put. Octagon heads stay put and give you a flat face to set down on. If your training space is also your living space, head shape matters more than almost anything else on this list.
The four sets, honestly
BowFlex Results Series SelectTech Dumbbells
This is the reference point. When a client tells me they want adjustable dumbbells and they have the budget for one good purchase, this is the name that ends the conversation. The dial mechanism is the part of the design the rest of the category copies, and it is the part that determines whether you are still using the set in five years or selling it on marketplace in eight months.
What it wins on is the thing you cannot see in a product photo: the change between weights is fast enough that it does not break your rhythm. A set that takes 40 seconds to change is a set you stop changing, and a set you stop changing becomes a 25 pound dumbbell with extra parts.
What it loses on is straightforward. It costs multiples of everything else here, and the honest math is that a beginner does not need it. If you are doing three sets of curls and some lunges, a cheaper set does that job. Where the SelectTech earns its money is a lifter running a real program with drop sets, supersets, and a partner who trains at a different weight than you do.
The 6-in-1 octagon set
This is the one I would hand a beginner who is building a first garage gym and wants options. The 6-in-1 Adjustable Dumbbell & Barbell Weight Set covers a dumbbell, a barbell, a kettlebell, and push-up stands, and the octagon heads are the detail I keep coming back to. Octagon anti-roll heads mean you can set them down between sets without chasing them across the floor, which sounds trivial until you have chased a round dumbbell into a wall for the third time in a session.
The 45 pound ceiling is the honest limitation. That is enough for a beginner through a solid intermediate phase, enough for high-rep accessory work forever, and not enough for a strong lifter doing heavy rows or pressing. If you are already moving real weight, this set is a supplement, not a replacement.
The composite construction is the other thing to weigh. Iron sand and cement composite heads are quieter on a garage floor than solid iron, and they are gentler on a dropped rep. They also feel bulkier in the hand at a given weight, because composite is less dense than steel. That is physics, not a defect. The included gloves I would treat as packing material.
The 2026 FDB2 set of two with the storage box
This is the set I recommend when someone tells me their dumbbells live in a hallway closet or under a couch. The 2026 FDB2 Updated Adjustable Dumbbell Set of 2 arrives as a pair, which matters more than people expect, and it comes with a storage box, which solves the problem that kills most home setups: the plates end up in four different places and the set stops being usable.
The anti-slip silicone grip is aimed at the exact failure point I described earlier. A smooth metal handle with no texture is useless once your hands are warm, and silicone gives you traction without the shredded-palm problem of an aggressive knurl. The trade-off is that silicone holds dust and gets slick when it is genuinely wet, so keep a towel nearby.
The 5-in-1 and 10-in-1 labeling is marketing noise and I wish it were not there, because it makes the set harder to compare than it needs to be. Look at the weight options and the storage situation, not the mode count. What you are really buying here is a tidy pair with a home, and for a lot of people that is the difference between training three times a week and not training at all.
The 5-in-1 nut-lock set with the 20 to 90 pound ladder
This is the most ambitious of the budget group. The Adjustable dumbbell set with the 20/35/45/55/70/90lbs ladder, an upgraded nut, and 5-in-1 conversion to kettlebell, barbell, and push-up stand is trying to be four products in one box, and the stated weight ladder is the widest here.
That ladder is the reason to look at it. If your training spans light lateral raises and heavier goblet squats, a set that states 20 through 90 pounds gives you room that the others do not.
The nut-and-collar lock is the reason to be cautious. It is the oldest, simplest, and most repairable mechanism in this category, and it is also the one that demands the most discipline. You check the collar before every set, or you learn why you should have. Thread quality varies, and a collar that walks loose under vibration is the classic failure of this design. On the plus side, when a collar eventually wears out, you replace a collar, not a dumbbell. The conversions are genuinely useful, but every mode is another set of small parts with a talent for disappearing under a bench.
Which one fits your training
Here is how I would actually decide, in the order I would ask the questions.
If you are new to lifting and your budget is tight, take the 6-in-1 octagon set. It gives you the most training options for the least commitment, and the 45 pound ceiling will not hold you back for a year or more. Octagon heads mean it stays where you put it, which matters in a shared space.
If your space is small and you want the set to stay tidy, take the FDB2 pair with the storage box. The box is not a gimmick. Equipment that has a home gets used, and equipment that lives in a pile does not.
If your program has grown past beginner work and you want a single purchase to carry you, take the BowFlex Results Series SelectTech. The mechanism is the proven one, the changeover is fast enough to keep your rest periods honest, and you will not be shopping again next year.
If you want the widest stated weight range on a budget and you do not mind checking a collar before every set, the nut-lock 5-in-1 set is the pick. Just be honest with yourself about whether you will actually tighten it every time, because that is the entire deal.
The trade-offs nobody puts in the listing
Adjustable dumbbells are a compromise, always. You are trading the feel of a fixed dumbbell for the footprint of a whole rack, and every set here makes that trade in a different place. A dial set trades repairability for speed. A nut-and-collar set trades speed for simplicity and a lower entry point. A composite set trades density for quiet and floor-friendliness.
The other thing I tell every client: buy the set that matches the training you will actually do, not the training you plan to do. A 90 pound ladder is worthless if you are doing 12 pound lateral raises and 25 pound curls for the next two years. A 45 pound ceiling is a wall only if you are actually pressing past it.
And buy a stand or a rack, or at least a dedicated spot on the floor. A pair of adjustables left in the middle of a room is a pair of adjustables that gets moved to the garage and forgotten.
What I am watching next
The interesting story in this category is not weight range anymore, it is the mechanism. The new designs are getting cleverer and more fragile at the same time, and the sets that last are usually the boring ones. I would rather see a well-cut thread on a nut-and-collar set than a fifth mode nobody asked for.
If you are choosing between these four, pick based on your ceiling, your space, and how much patience you have for maintenance. The mechanism is the product. Everything else is packaging.