This is a super common question, with some super easy answers (that lots of people try to complicate).
- The most aggressive the knurling, the more it fights slip
- The more your practise on a bar, the more comfortable it becomes
- Sharp bars hurt more at the start, but have a worthwhile payback (for us)
What is knurling
It’s the bit of the bar you grip that looks like a file. The more aggressive, the sharper and deeper the grooves. Aggressive knurling is normally associated with comp bars and more expensive bars.
Is it better?
A seasoned powerlifting or strength athlete will always prefer to train on an aggressive bar. For two reasons, their hands are already toughened and callused, and their deadlift form will be good enough that they don’t scrape their shins that often.
If you are a beginner or have soft hands, the first session on a sharp bar, your hands are going to hurt, and if you make the mistake of hitting your shin, you are going to bleed and be in pain in a way you will remember for a long time.
From a ‘holding more weight’ or ‘not slipping off your back on a squat’, yes, a more aggressive knurling is better every single time. The small slips in your hand create a worsened grip, which makes more slip, then your drop the bar.
From a getting ready for a comp aspect, yes, comp type knurling is better.
From a general training every day, I use straps, I don’t compete point of view – we’d personally still prefer it but to save some cash, and have less ‘tough’ hands, a less aggressive knurling may be better.
Real world results
If you’ve pulled on a bar with soft or old knurling, it's impossible to deadlift a lot without straps (in globbo gyms, I always use figure 8s).
Once your deadlift gets to a higher weight, in the real world, more aggressive is going to be better. If you’ve ever pulled on an axle, and been forced to grip on something so wide, you will know it does weird things to your entire strength system. You can have an axle 100kg under your deadlift weight and it feels like your whole body gives out, not just your grip.
Equally, if your grip is stronger, or you are wearing straps, mentally, it feels like you can break more off the floor.
Real world Feel
The ‘Hill Knurl’ is our softest, and you would recognise this as the grip on the nicest/newest bar at a globo gym. It's shallow compared to our other grips, so the knurling is hitting your skin, as well as the bar underneath. You could rub your hand sideways across this, and it would be uncomfortable at worst. Imagine a finishing file. It does not hurt in any way to grip.
The ‘Volcano Knurl’ (below) is our second most aggressive knurling. It's deeper, real world feel; imagine a more spaced out nail file (sorry, I just walked around my house rubbing things, and this was the closest). If you rubbed your hand sideways across it hard, it would tear your skin, and it will cut your shin on a bad pull.
The ‘Mountain Knurl’ (below) is a replication of a comp spec grip. It's quite deep, imagine a ‘b*stard’ file that has been used a little bit. If you rubbed wood against the knurling, it would definitely file it down. Unless you have been on these types of bars before, the first few sessions, your hands will hurt.
The dreaded shin drag
These days, we recommend everyone wears deadlift socks for that reason (it's not cool to bleed on bars). Even if your form is good enough that you only scrape one in a thousand deads, it's not cool to leave that gross blood that turns orange over time. PSA, if you do scrape, you need to get a proper cleaner on there, don’t be a jerk and just rub off with your towel.
Hand Size and Knurling
In general, stubby finger boys and girls won’t be able to hook grip, and will enjoy a more knurled bar, to get better grip.
Long thumb people that hook grip and love pain will less likely need super aggressive knurling (if you don’t understand what I mean, they are practically using their thumb as a strap and crushing it under their fingers so the bar doesn’t roll).
From running a gym, it does seem people with a longer hand getter better grip (at the start). From a training point of view, getting a strong double overhand has huge payback in all training.
Over under helps stop the slip (the bar is rolling into itself from both sides). This may gross some people out, but your calluses grow where the bar sits, and the knurling sinks into the callus. So, regardless of hand size, your body will adapt to the bar you are training on.
What bar should you get
For a home gym and enthusiast, I’d recommend the volcano. For a person on the stronger side who competes, I’d recommend mountain.
The only downsides to mountain, it's going to tear shirts if you use the same ones all the time and its going to make your hands rough. If you are one of those savages that pulls hook grip, its going to mess up your thumbs (but you guys are all used to that).
The hill knurl is more for beginners in PL or bodybuilding type movements, its fine, but you are unlikely to max out your dead on it if you pull 200+.
You have to clean your knurling. Please, or it's all a waste. If it is caked in gross old chalk, a lot of its function is lost. Some people used steel brushes, but that seems unnecessary to us. Just buy a stiff brush, add a little cleaning alcohol, and brush it off after it session. It takes a few seconds. As gross as it sounds, if you don’t, there is little bits of skin in there.
Bar slip and squats
A long time ago, I had a low quality bar slip off my tshirt (I sweat a lot). It was mid drive and my right shoulder and wrist took the brunt of it, and I was injured for a long time. I’ve seen multiple people slip grip on a deadlift and continue, then injure themselves (always drop a slip, unless it's to win some huge comp).
Since that time, if I’m in a globo gym on a cheap bar, I wear an A7 shirt. You can say my form sucks all you want, but 200+ on a cheap bar and sweaty shirt does not work.
Back when I had access to a PL gym, I would chalk my upper back and use comp spec bars to squat, and that security that a bar wouldn’t slip made heavy weights so much easier.
Hopefully that helps. It's somewhat difficult for us at times to write these types of articles, because we’ve had the privilege to use a huge range of bars over the last 20 years. If there is something else you need to know, we’ll update this article!