Olympic Plate Diameter – Inside and Outside Dimensions

By | 2017-10-26T23:42:45+00:00 June 8th, 2017|Categories: Equipment Guides|Tags: , , |0 Comments

Here’s some info that folks need sometimes on the sizing of olympic plates, including their diameter, hole size, and thickness.

Overall Diameter

The overall, or outside, diameter of an olympic plate is supposed to be 450mm (17.72″). This is the IPF (International Powerlifting Federation) and IWF (International Weightlifting Federation) regulation size.

This goes for most models of olympic plates, including:

  • Bumper Plates – Solid rubber plates used for the clean-and-jerk and the snatch in Crossfit and olympic weightlifting.
  • Powerlifting Discs – Solid steel calibrated plates used in powerlifting competitions
  • 45lb or 100lb Cast Iron Plates – Some 45lb and 100lb cast iron plates are made to the 450mm spec. This includes rubber or urethane coated plates that are only coated on the surface and are mostly cast iron. But models can vary from 430mm to 470mm.

Are they always 450mm?

Unfortunately not. I’ll explain.

There are two reasons for this specification:

  1. The bar shaft is sitting at an exact height of 211mm (assuming a 28mm diameter shaft) from the floor when the lifter begins a lift such as a deadlift or clean. .This is important for competition purposes. If you’re not competing, this doesn’t necessarily matter a whole lot. It also makes no difference for exercises like the bench press.
  2. Dropping the barbell is rough on plates, and if all the plates don’t reach the floor, the ones taking the shock load might not be able to handle it and can break. Even bumper plates are only engineered to take a little more than their own weight when dropped.
  3. If only some plates are touching the floor and there’s any slack in the hole sizing on them, you’ll end up with a jerky pull as you’re lifting some weight while still pulling slack out of the rest of the weights. Think of it like a coupler connecting railway cars, which is good for the engine because it can gain momentum as it pulls the slack out of each car at a time before it pulls the weight of all the cars, but it’s bad for you as a lifter because you need a smoother pull.

Some people gather plates over the years for their gyms and aren’t always able to get the same brand and model of plates each time. The odds of getting two brands of plates of a non-standard diameter to match up are pretty hopeless. However, if it’s 450mm diameter, your odds of getting some matching plates drastically improve.

For example, our York Legacy and Troy Premium plates are the same 450mm diameter and work great together. They’re both old-fashioned wide-flanged cast iron plates.

Our 45 lb economy plates are measured at 451mm. These are what are included in our lowest priced 300 lb olympic weight sets.

Any cast iron plate 35lb or lighter will be smaller. The diameters are only the same for 45lb and 100lb (when the particular model is even made in a 100lb size) plates.

Bumper plates are all the same diameter, regardless of weight, and only vary in thickness. They are more targeted towards the olympic lifting market, so the IWF specification is taken more seriously and they tend to meet the 450mm spec. Even so, Hi-Temp bumpers and some other brands like some of Rage Fitness’ bumpers are more like 17.5″ or 440mm.

Center Hole Diameter

weight plate hole diameter

In a perfect world, all olympic plates would at least have the same sized holes and all olympic bars have the same sized sleeves. That isn’t always the case.

You can’t fit a 2″ rod into a 2″ hole (without lots of pounding), so good Olympic bars have 50mm (1 31/32″) sleeves, and good Olympic plates have holes just slightly larger than 50mm, such as 50.4mm or 50.8mm (exactly 2.0″).

What happened at some point was manufacturers started making cheaper olympic plates with holes a little larger than 2″. That way plates with casting defects in the holes would still fit the bars. So they have a very sloppy fit, which is annoying for any type of lift you do off the floor, such as deadlifts, cleans or snatches, because you have to pull the slack out.

Because their plates were so loose, the manufacturers making these cheap plates didn’t care about the bar sleeves being exactly 50mm, so they made the bar sleeves a little larger and sold them with their plates in weight sets. That worked out well enough, because those weight sets were marketed towards people who didn’t know anything about weights anyway and the sloppy fit wouldn’t bother them. Today, even casual lifters more and more are conscious of quality and have access to better equipment instead of relying solely on their local chain sporting goods store. They tried to fit high-quality plates on a cheap bar and the plates got stuck.

Nearly all the olympic plates we sell on this website, such as Troy, Intek, and others, are made for a snug fit. One exception is our “economy” plates that are clearly described on the product page as being a more sloppy fit than normal. The other exception is all York plates. Several years back they made the decision to make their holes a little larger, and they stuck with that decision.

Virtually all the olympic bars we sell, including York, make their bar sleeves a perfect 50mm diameter. You can count on that. The only exception would be when once in a while we have a certain specialty bar, like a “fat” bar made entirely with 2″ (50.8mm) pipe down the shaft and ends. In any case like that we will clearly note the issue in the product description, with a note on what plates and collars are needed for it, to avoid any compatibility headaches.

Other fitness equipment retailers are often ignorant of the whole issue on sizing and just assume all olympic stuff will always fit each other. This is why it’s important to do your shopping with a company that understands what they sell.

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About the Author:

David Kiesling
David founded Adamant Barbell in 2007. He is into weight training, Crossfit, nutrition, hang gliding, snowboarding, mountain biking, and hackysack. He also owns a hang glider repair business.

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