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What Size Dummbell Collars/Clamps Do I Need?

I’ve got a pair of Olympic Dumbbells in my house, that I’ve just found in the garage, but unfortunately the collars/clamps have gone missing. I’m gonna buy some new ones, but I’ve no idea what size to get.

These are the ones I was going to buy, but as you can see they come in 4 different sizes - https://tinyurl.com/r8z6dpt

They come in 25mm, 28mm, 30mm, and 50mm. I’ve just measured my dumbbell handles, and they’re 6.5 inches (16cm) all the way around. But I still can’t figure out how this translates into millimetres.

Any help would be massively appreciated, as I need to order them ASAP to be here by tomorrow.


You’re measuring the circumference.

You want the diameter. To get that you just double the radius.

I believe an Olympic sleeve diameter is 28mm

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That’s all foreign to me haha. Sorry man, I’m not a dumbass, it’s just that maths was never my strong point. Is there something specific I need to do to figure out the diameter? I’ve got a tape measure.

I figured Olympic bars/dumbbells were the biggest they got, so I was gonna buy the 50mm ones if I couldn’t figure it out, but if they’re 28mm, then what are the 30s and 50s for?

Well I just measured ACROSS the end of the dumbbell instead of AROUND it, as shown in the picture below with the red arrows.

It came back as 50mm. I’m guessing that means I need to get the 50mm size?


Crap, you’re right. I misled you; I’m sorry.

Grip is 28mm; sleeve is 50mm. You’re exactly on point

No worries man, really appreciate it though, everyone makes mistakes :wink:

OP - math has practical applications, too. Yes, you could have measured the diameter right off the bat. But you knew the circumference was 16 cm. 16 cm is 160 mm. pi (3.1416) x D (diameter) = C (circumference), so C / pi = D. 160 / 3.1416 = ~50.9. Math doesn’t have to be your strong point, but it doesn’t mean you have to just never learn it.

The apocalypse is a perfect time to study up!


Ha. I was about to say the same. Finding the diameter is the opposite steps of finding the circumference.

Diameter x pi = circumference

Circumference / pi = diameter

Or, you know, just measuring the diameter

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16cm x 10cm/mm ÷ 3.14159 (pi) = 50.9mm

This is elementary school level math.

Lol - definitely the obvious answer. For me, I use hand micrometers on cylinders in pre-print form to determine diameter, but our crane system deals in circumference. Mic’s read in standard, machines in metric, engraving specifications in microns, detail of engravings in lines per inch or lines per centimeter, it’s conversions and basic geometry all damn day, haha. But I’ve never worked a job that didn’t in some way include a lot of some type of math. It’s just useful. And it’s literally everywhere and in everything.

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Math is so practical, it’s a shame they don’t teach it relative to practical use in jobs.

I’ve worked for one district that split the Highschool into four schools: business, career technical, art and something I can’t remember. Jr. Year, all the kids choose a path that interests them and the subjects are aligned.

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