The majority of lifters believe that all dumbbells are made of metal - a fact that is actually only true in a small percentage of cases, as dumbbells may be made of a variety of different materials and coatings that are not only cheaper to manufacture but also provide their own set of benefits that ordinary metals do not.
For the most part, the particular material a dumbbell is made out of will depend on its purpose and what brand it is, making the decision on what kind to purchase for gym owners and home workout enthusiasts a rather important one.
The majority of modern dumbbells are manufactured from mold-casted iron or treated steel and coated with an impact and friction reducing material like rubber, plastic or neoprene - all meant to protect both the dumbbell’s inner material and any object it may come into contact with.
Dumbbells can be made from a number of different materials, the majority of which are built to specifications of narrow margins so as to create a more accurate size and weight per dumbbell, especially in the case of the more expensive metals.
This particular material is most commonly seen in adjustable dumbbells wherein the weight plates attached to either end of the handle are cast iron so as to maintain high density and low friction within a smaller size - and is most often only coated with a thin material meant to protect the floor if the dumbbell or plates are dropped.
Cast iron dumbbells and weight plates meant for adjustable dumbbells are most often molded into shape during manufacturing and are paired with such coatings like urethane or a thin layer of rubber, making a cost-effective yet surprisingly durable dumbbell with only a few actual disadvantages.
More expensive and resistant to rust than its cast iron counterparts, dumbbells made from steel are also commonly seen in the manufacturing of adjustable dumbbell plates, dumbbell handles as well as many fixed-weight dumbbells, each of which make use of different coatings and weight sizes in accordance to their uses.
Due to the density and higher price range of most steel dumbbells, they are more often used by professional chain gyms or higher level lifters with their own home gyms of whom are aiming for higher quality equipment.
Steel dumbbells are generally heavier per cubic inch than other materials used to make dumbbells, with low-impurity cast iron being one notable exception to this.
As such, dumbbells of lower weight designations such as those used for plyometrics or high volume sets are less often made from steel and instead are made from plastic or other materials.
Certain types of fixed weight dumbbells are made of flexible but nonetheless highly durable forms of plastic.
This is most often seen in dumbbells of far lower weight than the sort made of metal or concrete, as the plastic material used to make these dumbbells is significantly lighter per square inch.
One benefit to the usage of solid plastic as opposed to other materials used in dumbbell manufacturing is the flexibility and low cost associated therein - allowing multiple pairs to be purchased for the price of a single pair of iron or steel dumbbells.
However, unless otherwise coated or made of a more resistant form of plastic, these sorts of dumbbells may be more susceptible to breakage than the usage of metal dumbbells instead.
Low cost and easy to manufacture at the price of durability, dumbbells made from solid concrete are relatively uncommon in commercial gyms but nonetheless hold a place as a low-budget home gym alternative to other heavy dumbbell materials.
Solid concrete dumbbells are often coated in a thick layer of impact-resistant material such as rubber or hardened plastic so as to prevent the weights from cracking or otherwise being damaged through regular use.
Though each of the materials previously listed are perfectly functional as dumbbell components, characteristics related to these materials
In terms of durability, not only does the core or inner material play a major factor - but so too does the type of dumbbell and what sort of coating encapsulates this inner material.
Nonetheless, dumbbells manufactured from stronger and denser materials such as iron or steel will obviously be more durable to direct impact and mechanical stress than their concrete and plastic counterparts, especially when it comes to accidents that may damage the dumbbell such as dropping them or being slammed into a dumbbell rack.
While this is not to say that plastic and concrete dumbbells are of poor durability, as they are indeed quite resistant to force as well - it is simply that, if durability is an important factor, one may find that investing in a set of metal dumbbells will serve them far better.
In addition to this, dumbbells with fixed weight are more durable than those of the adjustable variety; a fact that is more to do with how the dumbbells are built (i.e. fixed dumbbells are often welded or cast into a single object) than the actual material that makes up either kind.
Unlike in the case of comparative durability, it is in susceptibility to rust and similar forms of chemical degradation that concrete and plastic dumbbells are superior to their metal counterparts.
While the usage of coating can often mitigate this particular issue, plastic and concrete dumbbells do not share this inherent risk and as such are far better for use in outdoor gyms or similar environments wherein the inner material of the dumbbell may be exposed to high levels of moisture.
For gym owners without the luxury of excess space or casual exercisers wishing for dumbbells they can fit beneath their bed, choosing an adjustable set of dumbbells made of material that are heavier per square inch can greatly aid in saving space, especially in terms of incremental weight increases with an adjustable dumbbell.
It is generally pure cast iron that is the most dense and heaviest in comparative size, though steel dumbbells are also perfect for this purpose - while the density of concrete dumbbells will depend on a number of factors, and are often somewhat larger in size than metal dumbbells.
Plastic dumbbells are the worst choice in this particular category, often taking up quite a bit of space despite their relatively low weight, alongside the fact that very few brands of adjustable dumbbells are manufactured from this material.
Arguably the largest distinction between the various types of dumbbell materials, the cost of each dumbbell will usually vary depending on the brand and quality of said dumbbells - though the material that it is made of will also play a role in such matters.
For the most part, plastic and concrete are far easier and cheaper to manufacture and therefore will be sold for a more affordable price, whereas more expensive and labor-intensive materials that require advanced manufacturing such as steel dumbbells will be marketed at a higher price.
One should note, however, that the price of a dumbbell does not particularly indicate its quality, and there are many low quality steel dumbbells that would just as easily break or prove less useful than one made of plastic or concrete.
Less to do with what sort of material the weights at both ends of the handles are made of and more to do with the actual handles themselves, the dumbbell’s relative ease at being held by the exerciser will also depend on what sort of material the handle is made of.
Steel and iron handles with significant knurling will be far less slippery than plastic ones, for example - especially if the exerciser’s hands are sweaty, thus greatly reducing friction and increasing the chance that they will drop the dumbbells.
Fortunately, most concrete dumbbells will feature a metal handle, often with knurling or some sort of texture that aids in maintaining a proper hold over the dumbbell - placing such dumbbells at equal usefulness as their metal counterparts.
Not only does the inner material of the dumbbell’s weights matter, but so too does the material that coats these weights - and, in certain instances, the handle of the dumbbell as well.
The type of coating material a particular dumbbell is manufactured from will alter several aspects of its usage, such as the durability and longevity of the dumbbell, as well as the sort of traction it may have when gripped from one end.
The most common type of dumbbell coating, rubber greatly reduces the risk of the dumbbell’s weights cracking or otherwise being damaged when dropped, while still being relatively lightweight and small in size.
It should be noted that, despite their similarities, rubber and neoprene are in fact two different materials and as such will have slightly different price tags and longevity - with rubber being both cheaper and lasting somewhat longer except when in a humid environment.
Neoprene is a synthetically derived form of rubber meant to encase iron and steel dumbbells for protective purposes.
While neoprene shares quite a number of similarities with rubber in terms of function and durability, one characteristic where neoprene is superior is in its absorbency, wherein the material reduces the risk of slippage or of the inner metal material rusting by absorbing moisture in a manner that naturally produced rubber does not.
A synthetically derived material quite similar to rubber or plastic in durability and resistance to the elements, urethane is another excellent dumbbell coating that is most often used for higher-quality fixed dumbbell pairs, wherein it will lengthen the longevity of the inner metal and prevent damage to a dumbbell rack or the floor.
While urethane surpasses most other dumbbell coating materials in many respects, it is among one of the most expensive coatings - and rarely ever used for adjustable dumbbell sets, making purchasing urethane coated dumbbells an uneconomical decision.
Vinyl is a reinforced plastic material usually used to encase solid concrete dumbbells of the fixed weight variety, with the entirety of the dumbbell (including the handle) often being covered in the hardened plastic material for the purposes of protection and improved grip.
However, vinyl is somewhat less effective at withstanding the elements or sudden impacts than other dumbbell coating materials - as well as the fact that it is rarely ever used for heavier fixed weight dumbbells, instead seeing use in beginner levels of weight.
This makes vinyl coated dumbbells a better purchase for novice exercisers or individuals looking for light weight dumbbells that they may use in plyometric training or similar modalities.
Choosing the correct type of dumbbell and what sort of material said dumbbell is made of will depend on many factors, such as what the exerciser’s purpose for these dumbbells are, their own relative training level and their budget.
For the most part, unless the exerciser is an intermediate to advanced lifter with a home gym (or a public gym owner), they may be better served purchasing adjustable dumbbells made of cheaper materials such as concrete or plastic, as this will not only save them money but also allow them to become more familiar with dumbbell usage in general, something that may cause more expensive weights to be damaged otherwise.
1. 汤汉忠. Production process of dumbbell, Patent Number CN103212185A Filed on 2013-05-06 Patent Issuance Pending
2. (宪勇, OMNI RESOURCES INTERNATIONAL TRADING (TIANJIN) Inc Process for manufacturing dumbbell and barbell products Patent Number CN102189256A Published 21, September 2011)