Knurling is a critical factor when you’re buying a barbell.
It’s an often misunderstood feature because there’s so much nuance.
As someone who owns over 60 barbells, I can’t tell you how many people have asked me, “Adam, why do you have so many bars – don’t they do the same thing?”
In the simplest terms, yes, they all make you stronger.
But it’s not that simple in reality because each barbell has its own characteristics.
Whenever I get that question, I invite them over to my bar storage and ask them to grip a few of them.
When they do, it immediately begins to make sense.
That’s because every barbell feels different. Sure, some may feel similar, but they’re all unique.
Shape, depth, density, and coating, are just a few elements that give barbell knurling an identity.
In this article, I’ll break down everything you need to know about knurling, including the common types and most important features. I’ll also point out some defects to look out for and how to keep your knurling performing well for years.
Let’s dig in.
The Importance of Barbell Knurling
Knurling is used to enhance your grip on barbell movements. Knowing your training style and goals goes a lot way toward determining which knurling is right for you.
Again, knurling is supposed to enhance your grip.
If you’re a powerlifter deadlifting serious weight, passive knurling will detract from your grip because it won’t provide enough bite.
If you’re a CrossFitter training with high reps, aggressive knurling will detract from your grip because it will eventually start to hurt.
Knurling should be comfortable enough to let you perform the entire workout and effective enough to hit the actual lift.
Knurling also has secondary benefits, including helping to line up in the middle of the bar, ensuring consistent hand positions, and more.
Three Types of Barbell Knurling
There are three main types of knurling you’ll find on a barbell. Each has advantages and disadvantages based on lifting style, rep schemes, training volume, and general preferences.
We can analyze each type of knurling through the lens of a landscape’s elevation and topography. Each image below is from my own barbell collection – I shot all at the same focal length.
Great For: Beginners, General Barbell Training, High Reps & Volume, Sensitive Hands
Found On: Multipurpose Bars, Weightlifting Bars, and Some Specialty Bars
Knurling with a hill profile has a pattern with smooth, flat tops. This is the most passive barbell knurling and is commonly found on multipurpose bars, training bars, and some specialty bars.
A hill knurl is typically shallow, meaning it’s not pressed deeply into the shaft. Shallow profiles are considerably less aggressive than those with more prominent elevations. While I prefer more aggressive patterns, this type of knurling certainly has a place in training.
I recommend it for beginner lifters and those who train with high reps/volume or have sensitive hands. Passive knurling is generally much more hand-friendly. In other words, the likelihood of tearing calluses or experiencing pain is low. However, this type of knurl is not a great performer when it comes to heavy training and PR attempts. You’ll likely need to aid your grip with weightlifting straps or chalk.
Great For: Most People, All Training Styles
Found On: Multipurpose Bars, Weightlifting Bars, Powerlifting Bars, and Some Specialty Bars
A volcano knurl pattern is the most popular type because it bridges the gap between passive and aggressive. You can absolutely have an aggressive volcano knurl, but they typically provide a more moderate feel. They’re commonly found on multipurpose bars, Olympic weightlifting bars, and power bars.
You can tell that a knurl has a volcano profile by looking at the tops. You’ll see noticeable craters on each point – you know – like a volcano. Each of these craters effectively creates four contact points within each point, increasing surface area in the hand.
The depth of volcano knurling is one of the biggest influencers over texture. Where a hill knurl is passive across manufacturers, a volcano knurl can differ significantly. The Rogue Ohio Power Bar is a great example of a deep volcano knurl, while the American Barbell Grizzly Bar is much shallower. When comparing the feeling of both bars, the Ohio Power Bar is considerably more aggressive despite the Grizzly also being a power bar.
I recommend volcano knurling to most lifters because it’s well-balanced and highly accessible. You can use it across a wide range of movements and rep/volume schemes. For example, the Rogue Ohio Power is an ideal everyday power bar that you can use during hypertrophy blocks or PR attempts.
Great For: Advanced Lifters, Heavy PR Attempts, Deadlifts
Found On: Powerlifting Bars and Some Specialty Bars
Mountain knurling is the most aggressive type and is almost exclusively found on power bars. This is a niche knurling pattern that best serves advanced lifters training lower reps and heavier weights.
As the name implies, this type of knurling has prominent points resembling mountains. Instead of volcanic knurling, where the pressure is spread across four points, a mountainous pattern delivers a single, more focused contact point.
Mountain knurling can vary from bar to bar in the same way that a volcano knurl can. Generally, a deeper pattern is more aggressive, but sharpness plays a bigger role in this variety. Some bars have shallower profiles with rounded-off points, while others are deep with sharp tips.
For example, the American Barbell Mammoth Bar has a shallow, rounded knurling pattern. Despite being ‘mountainous,’ it’s less aggressive than even some volcano knurls. On the other hand, the REP Power Bar EX has deep, sharp points, making it one of the most aggressive power bars on the market.
I recommend mountain knurling for advanced lifters looking to train in the 1-3 rep range. This type of knurling is more likely to cause hand discomfort, open up calluses, etc. If you’re buying just one barbell, I don’t recommend one with mountain knurling. However, it’s an excellent supplemental knurl for lower reps and heavier weights.
Knurling Density Makes a Big Difference
Have you ever been to a circus or watched a magic show where someone lies on a bed of nails? You think for sure that they’re going to get up with puncture wounds all over their back. Then they add weight on top of them, and you think they’ll impale themselves right there on stage.
Yet, they stand up and take a bow, seemingly in no pain at all.
The nails aren’t fake – and it’s not an optical illusion – so how is it possible?
The answer is density, and it’s a key factor in knurling aggression.
I often use the term ‘points-per-square-inch’ when describing the density of a barbell’s knurling. When knurling has a greater density/higher points-per-square-inch ratio, it more efficiently spreads the pressure throughout the surface area (your hand) and reduces aggression.
Think about the magician. They’re lying on a platform with thousands of tightly-packed nails. Because of this, pressure is distributed across their body. If they were lying on only a few nails, the pressure would be tremendous since all the force is going into a few areas. That would be a much different and bloodier outcome.
Density is where barbell knurling can become very nuanced. By adjusting density, you could take the same depth and sharpness and increase or decrease how aggressive it feels.
All Olympic barbells have knurl rings to help you position your hands. These rings are narrow (~1/8″) sections of smooth steel placed within the knurled area. Knurl rings are important for two reasons:
First, they allow you to train with consistent form by getting lined up in the same spot every time. Without knurl rings, you’d be guessing where to put your hands, leading to inconsistent results and possibly an unbalanced barbell.
Second, different lifting styles require specific knurl ring placements. Power bar rings are set 31.8″ apart, and Olympic weightlifting rings are set 35.8″. For example, IPF rules mandate that your hands cannot exceed 31.8″ (81cm) apart when performing the bench press. By ensuring your entire forefinger is on the knurl ring, you’re lifting within the rules.
Multipurpose barbells include dual knurl rings so that you can perform powerlifting and Olympic weightlifting movements.
Standard barbells, which are less common and accommodate 1″ weight plates (vs. 2″ Olympic plates), may include dual knurl rings or none at all.
While all Olympic barbells have knurl rings, not all have center knurling. Center knurling is a knurled area in the middle of the bar spanning 4″-6″ wide. This can be beneficial in two ways:
First, a center knurl can help you line up consistently in the middle of the bar. Without it, you may line up slightly off-center and create an unbalanced bar. Knurl rings can help with this too, so it’s not a deal breaker if the bar doesn’t have a center knurl. In fact, it’s fairly common not to have one.
The second benefit is that it can provide additional tactical feedback when performing movements like back squats. Some lifters, especially low bar back squatters, prefer center knurling.
A downside to center knurling is that it can be uncomfortable in the front rack position. To mitigate this, companies will either not include one, or they’ll make a more passive center knurl than the rest of the bar.
I prefer bars with center knurling, but it ultimately comes down to preference, lifting style, and specificity. All power bars and most competition weightlifting bars include a center knurl. Multipurpose bars and training bars may or may not include them.
Barbell Coatings and How they Impact Knurling
I mentioned above that density is one way to influence texture without changing the knurling profile. You can accomplish the same with different barbell coatings. Barbell finishes primarily impact two things:
- The feeling of the barbell
- The bar’s resistance to oxidation/rust
Within barbell finishes, you have applied coatings, conversion coatings, and no coatings.
Conversion coatings (e.g., black oxide) and no coatings (e.g., bare steel/stainless steel) provide the best texture since they don’t interfere with the knurling.
On the other hand, applied coatings (e.g., hard chrome, zinc, and Cerakote) reduce texture because they fill in some of the knurl depth.
Therefore, this is another lever manufacturers can pull to change the knurling aggression without actually changing the knurling.
Oxidation resistance, cost, and aesthetics are other considerations.
Defects to Look for in Barbell Knurling
There are three issues to look for when inspecting a bar’s knurling:
- Double Tracking – Barbells are knurled using a lathe. When the knurling wheels become misaligned, they can cause double tracking. This produces an unwanted pattern that can affect the feel and look of the barbell.
- Feathering – Feathering is another defect that typically affects the transition between knurled and smooth steel. This is where the knurling gradually transitions from full depth to low depth before transitioning to smooth steel. It can also impact the feeling and look of the barbell.
- Overapplied/Uneven Coating – The final thing to look for is any sign of overapplied or uneven coating. For instance, if the manufacturer applied black zinc more heavily to one area of a bar, it could fill in more depth and impact the texture of the knurling.
Thankfully, these defects aren’t all that common. When they do exist, they’re mostly found in areas where you’re not touching the bar. Some companies, like Rogue, will identify bars with these issues and sell them at a discount.
If you discover your bar has these issues and you paid full price, it may be worth reaching out to the company. They may offer a credit or replacement.
Getting the Most out of your Barbell’s Knurling
As you use your barbell, the knurling can get filled with chalk, sweat, blood, bits of UHMW, etc. I strongly encourage you to brush it out every time you use your barbell. This will keep your knurling clean and feeling great while also helping to fight oxidation.
I recommend using one of these as a part of your barbell maintenance:
I’ve used both with great success.
Do All Barbells Have Knurling?
All traditional Olympic barbells have knurling ranging from passive to aggressive. However, not all specialty barbells have knurling, depending on the bar type and manufacturer.
What is the Best Type of Knurling?
The best type of knurling is that one that matches your preferences and lifting style. Knurling texture is very subjective, but I recommend most people start with a moderate profile before deciding if they want something more passive or aggressive.
Will Knurling Improve my Grip?
Knurling can enhance your grip while lifting, but you must keep goals and training in perspective. For instance, using a very aggressive bar for high reps and volume may detract from your grip due to discomfort. Knurling will also not improve your grip strength.
Knurling is one of the biggest differentiators when comparing barbells.
It’s an essential component that directly impacts training and comfort.
With different shapes, elevations, densities, coatings, and more, knurling is a great way to customize your barbell training experience.
Now all you have to do is get out there and train!