# Why do some weights(dumbbells/barbarbell.. Etc) make our joints pop compared to another equipment with the same weight?

I have noticed that the dumbbells i use at home make my joints pop even though they have the same weight as the dumbbell i use at gym but different shape,the dumbbells i use at gym have the same weight none of them make my joints pop, what causes this?

• Are you certain that the only variable being changed are the types of dumbbells? – C. Lange Feb 26 '20 at 15:52
• @C. Lange i will try to calculate the tolerance of the dumbbells when i get home. – Zheer Feb 26 '20 at 22:09

This is kind of vague, but my first thought would be that even if they show the same weight, they are not the same weight.

When weights are made they are made with a tolerance, usually the more expensive brands are +- 1% whereas the cheaper ones can go up to +- 10%> this may not seem like a lot but dumbbells have weights on both sides.. picture a 100 lb dumbbell. 50 lb on each side, one side could have -10% while the other has +10% making one side 45 and the other 55 and it could seem off balanced. Or each side could have a +10% making it 110 lb dumbbell in one hand and 100 in the other.

I would assume your gym, whether they are expensive or not, has dumbbells you use more often and are used to. Then when you're home and use yours which could weigh more, or even not weigh correctly. CAP is known for having big weight tolerances. Even if your weights are a pounds heavier at home it's still more than your used to.

Some dumbbells also have wider grips. This could be the issue too.

Otherwise if it's not this, then it could be something else as this really isn't a common problem. Your joints should never pop, so either the weights too heavy or you need to go to a physical therapist to get evaluated.

• Taking your word for the tolerance, which seems plausible, the kit sold for gyms is intended to stand up to much more than kit sold for domestic use. This should mean tighter tolerances on dimensions and therefore weights. You may be able to test them at home using a set of scales under one side and a block (of the same height as the scales) under the other. Positioned the same but rotated 180° the scales should read the same. Of course comparing the weights of a pair is easier than that] – Chris H Feb 26 '20 at 11:25
• Adding on to what Chris H said, you can buy machines plates for barbells or for adjustable dumbbells which have lower tolerances. Cast iron typically has higher tolerances unless it's a premium brand like rogue fitness. Before you buy any plates or dumbbells in the store you can weigh them to make sure they are at least close enough in weight in the pair itself. – Ace Cabbie Feb 26 '20 at 17:34
• @Ace Cabbie if i but two plates from the same brand, there won't be any tolerance, am i right? – Zheer Feb 29 '20 at 19:54
• @zheer each brand promises their own tolerance.. but all weights have a tolerance . So if you bought a brand with a +-1% tolerance, that means each plate could differ and weigh 1% more or 1% less from each other even if it's the same brand. Different brands are fine to use actually but some have higher tolerance than others. It could still be the desired weight though. Its best just to weigh them in the store. Smaller weights aren't necessary because naturally 1 or 5% of 10 pounds is incredibly insignificant – Ace Cabbie Feb 29 '20 at 23:21
• Another thought, that only really applies at the light end of the range: some cheap dumbbells aren't even metal, they're sand or cement encased in plastic. They're still cast but subject to more variation in packing and material composition. These are likely to have a worse tolerance – Chris H Mar 2 '20 at 14:35