The Nautilus Bowflex SelectTech adjustable dumbbells are probably the best "dial dumbbells" today. The basic set comes with a base unit to hold the weight plates and the "core" of the adjustable dumbbell, but there is a separate dumbbell rack available. These quick change dumbbells from Bowflex come with a 2 year warranty on parts, 5 years weight plates and 1 year warranty for labor.
Just shy of 16 inches in length, these dumbbells are pretty long. Unlike the PowerBlocks or Ironmaster, the length of the dumbbells remains the same regardless of the weight you select. This can be awkward and may take some time to get used to since the dumbbell is very long, even at 5 lbs.
The weight on the Bowflex dumbbells can adjust from 5lbs to 52.5lbs. Because of the maximum weight of only 52.5 lbs, you might be better off with the PowerBlock Elite Set or the Ironmaster adjustable dumbbell set If you plan on building huge muscles and getting super strong (the maximum weight on those dumbbells is about 120-130lbs) .
How it Works
Basically, you turn a dial on the SelectTech Dumbbells to the weight that you want until you hear a clicking sound, and you're set. Once the weight plates are locked in, simply lift the dumbbells from the base and you're good to go. You'll need to dial the knob on both ends of the dumbbell to alter the weight, however.
For example, if you wanted to us 30 lbs for each dumbbell, what you do is adjust the knobs on each dumbbell so that "30 lbs" is selected. In total, you'll need to adjust the knobs 4 times. The weight change process is pretty fast (only a few seconds), so it's not that tedious.
There are 15 weight settings for this dumbbell, ranging from 5-52.5lbs.
The "Off Set Weight Selection"
Now here's where you'll need to do some math.
But before we get into that, tradition dumbbells are symmetrical. Meaning, the weight is balanced with equal weight on both sides of the dumbbell.
With the Bowflex adjustable dumbbell, you can set one side of the dumbbell heavier than the other.
Now back to the Bowflex dumbbells, let's say you wanted to use 25lbs with one side heavier than the other. Simply adjust the knob to 30 lbs on one side of the dumbbell, and on the other side to 20 lbs.
The total weight is 25 lbs, BUT, one half of the dumbbell is 15 lbs, and the other half is 10 lbs.
But note that after you're done your set, you'll have to return the adjustable dumbbell back to the base in the same position that you removed it (the weight plates have to set back into slots of the base).
The offset weight option might be good or bad for you, depending on how you view it. Personally, I prefer symmetrical weight on both ends of the dumbbell, but there are advantages to unsymmetrical dumbbells. If you're doing exercises like a dumbbell curl with a dumbbell one side heavier than the other, you'll work your bicep in a different way than symmetrical dumbbells.
You'll get variety with the adjustable Bowflex dumbbells that tradition dumbbells can not provide.
Although the Bowflex adjustable dumbbell is good, there are some down points as well. Here's a summary of the Pros and Cons of these dumbbells:
o Easy and quick to change to your desired weight
o Unrestrictive dumbbell handle-allows you to perform all the exercise you can do with regular dumbbells
o You can add a new dimension to your workouts with the offset weight selection feature
o Does not take up much space (replace 30 dumbbells)
o VERY slick looking dumbbell weight sets
o A little pricey for these dumbbells
o For all you bodybuilders and serious weight lifters, the maximum weight of 52.5 lbs for each dumbbell is probably considered a warm-up weight for you.
o You can not upgrade the weight of the dumbbells
Overall, these dumbbells are great if you're not a bodybuilder or a serious weight lifter, but if you want free weights and if you do not mind the price, the Nautilus Bowflex 552 SelectTech dumbbells are a good buy. If you know that 52.5 lbs is too much for you to handle, then the Bowflex SelectTech 220 model (which adjusts to 20lbs at 2.5 lb increments) may be more suitable for your needs.