Can You Fit All Weight Plates On All Barbells? 1 Or 2 Inch?

Have you found a good deal on a set of weight plates or a barbell but are not sure if everything will fit together? Here’s what you need to know about barbells and weight plates fitting together.

The diameter of the ends of a barbell and the diameter of the inner hole of weight plates have to be matched to fit together securely. Common diameters for barbell ends are 1” or 2”. Weight plates with a 1” hole will never fit on a 2” barbell. 2” plates can work on a 1” barbell with an adapter.

Read more about the fitment of weight plates on barbells and what is the best choice for your situation below.

How do weight plates and barbells fit together?

Barbells and weight plates are super simple in principle. You’ve got a metal stick and heavy discs with a hole in the middle. To produce a good barbell and good weight plates is a bit more complicated than that but that’s the basis.

You slide the weight plates on both ends of the barbells and want them to stay there for the duration of the exercise and not slide off easily. But at the same time they should be easy to put on and take off. That is accomplished by matching the size of the inner hole in the weight plates to the diameter of the bar at the ends of the barbell (sleeves).

If the hole in the weight plate is smaller than the sleeves, they obviously won’t fit on there. If it’s too big, the plates will be too loose on the bar and can wiggle around during lifting. Both are bad although the second

The solution is of course to match the hole diameter and the sleeve diameter. If they are (almost) the same, the fit is tight and the plates won’t move around during lifting but are still easy to put on and take off the bar.

Common diameters for the sleeves (end parts) of a barbell are 1” or 2”. A 1” weight plate should only go on a barbell with 1” sleeves. 2” weight plates should only go on barbells with 2” sleeves.

Suggested: Dimensions of Olympic barbells

Barbells and weight plates will often be advertised as “Olympic”. That means they have 2” holes or sleeves. On a barbell that often means the sleeves can spin separately from the shaft of the bar. This has some benefits over fixed (1”) sleeves. 2” is also more common nowadays.

Want to quickly figure out if your barbell or sleeve is 1” or 2”? The width of your thumb is roughly 1”. So if the sleeve or hole diameter is about one thumb wide it’s 1” if it’s about two thumbs wide it’s 2”. Sure, this is not an exact measure but since the options are 1” or 2”, this is an easy way to figure it out.

The diameter of the inner hole of weight plates and the diameter of the sleeves of a barbell should be matched for them to fit together safely and securely. Common diameters of sleeves and plate holes are 1” or 2”. Mixing and matching barbells and plates with different diameters won’t work well.

Virtually all barbell and weight plates have a 1” or 2” fitment so just matching your set to that size will work.

Certified barbells and plates fitment

Barbells with a 2” spinning sleeves are often called Olympic bars. That’s simply because the style of thin shaft with thicker sleeves is what is mandated for the Olympics and most other weightlifting competitions. However, if you get a real (certified by the IWF) barbell the sleeves measure 50 millimeter. 1 inch is 25.4 mm and 2 inch is 50.8 mm. So you have to be a bit careful with really high quality barbells and weight plates that are certified for official use. Those barbells follow the dimensions in millimeters and the tolerances are very small. The IWF allows a tolerance in dimensions from +0.1% to -0.05% for the barbells and plates.

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If you’re using certified barbells AND weight plates, you won’t have a problem, they’re made to fit each other perfectly and you’ll get a better fitment than most other combinations.

Cheaper weight plates and barbells can have much bigger tolerances and are often built using the 1” or 2” measurement. That means weight plates sold as 2” can have a hole that’s as big as 52 mm. This will fit on a certified barbell no problem although the fitment is not super tight but not too loose to be a real problem. In 99.9% of the cases, 2” plates will fit on 50mm barbells perfectly fine.

The other way around can be an issue though. Certified weight plates will have a tight fit on a 50 mm barbell. So if yours is 50.8 mm (2”), this can mean it doesn’t fit. It depends on your specific combination but it could be a problem. However, I don’t see why you would buy very expensive certified weight plates and then go for a cheaper barbell so this situation is pretty rare in real life.

Get a 1” or 2” barbell and weight setup?

If you’re shopping for a barbell and weight plate set, should you go for one that has 1” or 2” weight plates and barbell?

Unless you already have a 1” barbell or weight plates, I’d always go for a 2” setup when buying both parts new. A 2” barbell has a few benefits.  

  • There is a lot more choice of barbells that have 2” sleeves and the high quality barbells will all have 2” sleeves. (Buying a barbell with 2” sleeves doesn’t guarantee a high quality bar though)
  • There is a bigger choice of weight plates.
  • 2”/50mm barbell sleeves spin separately from the shaft. This is a necessity for Olympic lifts (Clean & Jerk, Snatch). But even on common gym lifts like a squat, barbell bench press, etc. rotating sleeves can take a lot of stress of your joints.
  • Having 2” weight plates makes upgrading/changing barbells easier.
  • 2” weight plates can be made to fit on 1” bars and machines with an adapter but not the other way around.
  • Most plate loaded machines take 2” weight plates.
  • 2” weight plates and barbells will fetch a little bit more money second hand.

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The only benefits of going with a 1” setup is the price. 1” sleeved barbells are often cheap and 1” weight plates can sometimes be had for low prices second hand. So if money is your only concern, a 1” barbell and plate set can be better. However, if you’re buying both the barbell and weight plates new, the price difference is not big enough to miss out on the benefits of a 2” setup for.

1” barbells might be cheaper but the quality is also lower on average. Chances are you’ll want to upgrade the barbell after a while but with 1” weight plates this becomes very difficult. Because almost all good barbells have 2” sleeves you’ll also have to get new weight plates if you want to upgrade your barbell. So starting with a 2” setup leaves more options open for later.

Can you fit 2” weight plates on a 1” barbell?

1” weight plates on a 2” barbell is never going to work. It just doesn’t fit unless you’re willing to do some serious drilling and hacking up of your plates (bad idea, you’ll probably break the plates).

But what if you’ve already got a barbell that takes 1” weight plates? Can you make that work?

Of course the 2” weight plates fit on a 1” barbell easily. A little too easy actually. The plates will be very loose and can slide off easily. Even if you would use very strong barbell collars to prevent the plates from sliding off, they can still move around so easily it can create instability during a lift.

Imagine doing a heavy squat but because your form isn’t 100% perfect the weight plates start wiggling around. If several hundred pounds starts swinging on your back, you’re going to move with it and ruin your lift.

There is a very simple solution to this problem though and it’s an adaptor sleeve. It’s a simple sleeve that slides over a 1” barbell (or other piece of equipment that takes weight plates) and fills up the gap to 2”. The adapter secured in place with a screw so it doesn’t fall off easily. Now you can safely use 2” plates on a 1” barbell without them moving around too much. Of course using barbell collars to prevent them from sliding off is still advisable.

Make sure to get a metal adapter because the plastic ones wear out a little too quickly to use regularly for an extended period of time.

What about specialty bars and machines?

Does the information above only go for normal barbells and are specialty barbells different? And machines?

Specialty barbells are things like;

  • EZ curl bar
  • Squat bar
  • Hex bar

Most gym machines have a weight stack you put a pin in to choose the weight but some are actually loaded with plates. Leg press machines commonly have this for example.

Are the weight plates used for specialty bars and machines any different than for a normal straight barbell?

No. All specialty barbells and plate loaded machines will still have the 1” or 2” sleeves/pegs for the weight plates. So the same weight plate set you’re using for a barbell will still fit on anything else that takes weight plates as long as the diameters match. Adapter sleeves can also be used on specialty bars or machines.

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