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Why Do Metal Weights Feel Heavier

Why Do Metal Weights Feel Heavier? (Explained)

One of the best things about the gym is that it’s just you vs the weights and I’m sure many reading this have heard “philosophical” phrases saying no matter what life throws at you, a pair of 45s in the gym is always a pair of 45s. 

Well, if you’ve ever trained at home, and then at a range of different gyms you’ve likely found that not all 45lb plates feel the same. In fact, despite what the label says, certain types of weights always seem to feel heavier! 

One great example is a metal (iron) plate. In this article, I’m going to answer the question “why do metal weights feel heavier” (because they do), and see if the weight you think you’re lifting is accurate or not. 

Why Do Metal Weights Feel Heavier?

If you have had the opportunity to lift both metal and rubber weights, you might have noticed that metal weights can feel heavier. Don’t worry, you are not going crazy because there are a few reasons why this is happening. Many people have reported that metal weights feel significantly heavier. 

Personally, my first weight set was a vinyl and cement set of weight plates with a spinlock dumbbell and 5ft Barbell set. What I didn’t know at the time while training in my room is that a 5ft barbell does not weigh the same as a 6ft, 45lb barbell in the gym. 

I found that out when I put what I thought was 30kg (I’m UK based so use the metric system) on the bar to bench press and nearly crushed myself with what was actually 50kg total! 

The 25lb vinyl weight plates were larger than a number plate or 45lb iron plate. This already tricks your mind as you think you are lifting more than you actually are. When you use an iron set of plates though, for some reason they just automatically feel much heavier. 

So, why is that happening?

The first reason behind this could be that the iron weights are actually heavier

You can test that by using a scale – but be careful not to break it. Some regular gym-goers have done this and noticed that the difference between iron and rubber plates can be five pounds or even more. This is a significant difference, but it largely depends on the quality and calibration of the weights.

Cheaper, economy-grade weights are not calibrated properly and can be much heavier or lighter than what the number on the side says.

Also, if the iron weights are rusty, that can have a major impact on the weight as well. Even if the rust is not very noticeable, it can slightly increase the weight due to oxidation, which can add up quickly if you are lifting several iron-weight plates.

Another major factor is the diameter of the plates themselves. Metal weights typically come in a few different sizes, depending on the weight. Rubber plates, on the other hand, are usually the standard diameter of 45 cm and the only difference is the thickness. This can help with weight distribution as well as the bar whip.

The increased leverage bends the bar more, which is called barbell whip, and it makes the weights feel lighter, especially when doing heavy deadlifts. But bar whip goes both ways and it can make a lift much harder to do, such as the barbell squat.

Last but not least, it could all just be in your mind. When carrying the weights around the gym, the design of the weights can affect how heavy the weight feels in your hands due to comfort.

Also, larger metal plates might look more intimidating than using several smaller ones. It also affects the weight distribution, so experiment to see what suits you.

Are Iron Weights Heavier Than Rubber Weights?

If we are talking about high-quality weights, the deviations are minimal. Both iron and rubber weights can be calibrated to be extremely accurate, but they are still very different.

Cheap rubber weights can be very inaccurate and be several pounds lighter. Use a scale if you want to be absolutely sure that there is no difference between the two.

Also, iron weights can rust, which can make them heavier. This is because the iron in the weight reacts with oxygen and water, which increases the weight of the plates on a molecular level.

When speaking of dumbbells, those that are made of rubber can have a very different weight distribution than the more traditional dumbbells that use iron plates. This, along with a difference in the grip design and material, can make a major difference in how heavy the weight feels – even if the weight difference is marginal.

You can test this out yourself by doing a set with one type of dumbbell and then repeating it using the same weight but a different type of dumbbell. Even if the dumbbells are the exact same weight and you tested it on a scale, they can still feel very different due to the grip and weight distribution.

It’s similar to grabbing a broom. If you grab a broom in the middle, you can easily lift it up and down using just your wrist. Grab it by the end though (opposite end to the brush), and it becomes almost impossible to move it with just your wrist. 

The same is true with dumbbell or weight plate designs. 

Why Do Weights at Home Feel Heavier Than in the Gym?

Several factors can make weights feel heavier at home than in the gym. If we are speaking of barbells, you might be using a lighter barbell in the gym without even knowing it. The standard Olympic barbell is 20 kg, which is around 45 lbs, but lighter and/or shorter barbells are also quite popular.

More importantly, a good gym will use branded and reputable weights. If you’ve ever noticed weight plates that are different colors, this will be because they are Olympic regulation plates and need to be calibrated to an exact weight (very marginal room for error).

Regular weight plates are much less regulated and therefore have a much higher variance depending on the brand. 

Quality control is an issue for less reputable brands so buying weights for a home gym could mean they end up heavier than what the plate or dumbbell states. This is good for getting more value for your money but definitely not good when it comes to tracking your strength and lifting numbers. 

And when speaking of machines, such as the cable machine, the weights could be mislabeled.

This is a common occurrence and you might think that you are lifting 50 kg in the overhead triceps extension when it is actually only 50 pounds. But instead of paying attention to the numbers on the plates, pay attention to how the weights feel instead. This will give you a good estimate.

Of course, it could again all just be a psychological trick. When you are in the gym, you are focused on only one thing, whereas at home, many things are happening around you that could steal your attention.

Also, you may have less space at home, which can be a major factor as well. Or it could be that you have warmed up better at the gym.


You might think metal weights feeling heavier than other materials (vinyl, rubber, concrete) is all in your mind and psychological. Iron weights definitely look heavy compared to other weights and psychology plays a big role in strength training but it’s not all in your mind. 

Metal weights, in many instances, will feel heavier than other materials and this is due to a number of factors. Weight design, rust, density, and diameter of iron weights can all influence how a weight feels when lifting and it’s certainly true that metal weights can feel heavier. 

In reality, the difference should be marginal and if you’re really struggling with iron weights, it would be worth weighing them and trying to lose the physiological viewpoint that could be holding you back.