Measuring tire circumference

Learned, and forgot.

 

they teach common core nowadays.

you might visit a sewing shop and get a cloth seamstress tape that will not have bubbles in it when you go around the tire...

 

I don't think that would be near long enough and would introduce too much error by measuring in pieces.

A quarter inch tape won't have any bubbles. They're hard to find longer than 10 feet though.

 

Go to the tire manufacturer's website and look it up. Easy as pi.

 

Haha I see what you did there

 

Are you sure? Pi x radius squared is the formula to solve for area. Circumference is pi x diameter.

 

Correct Norhern. Circumference = 3.14 x the outside tire diameter. The other formula mentioned s for calculating the area inside a circle

 

If you look at the title to the youtube video I posted I had corrected my mistake. I don't use these type of calculations very often lately-- at least 20 years.

I worked on the new Cypress Freeway in Oakland CA years ago. The pilings we drove for the new column foundations were 42 inch pipe 70 feet long. Drive it down to about 4 feet above ground then weld another 70 footer on top of that and drive it down and cut it off at the proper grade a few inches above the bottom of the cofferdam which was 15 feet deep. The cofferdams were hexagon shaped, with one piling in each corner and piling in the middle. We'd then drill out the bay mud from the pilings 70 feet down, drop in a 20 foot rebar cage inside the pipe piling with about 8 feet sticking above the pipe and fill them with concrete.

That is where we had to be good at the math, 7 pilings 70 feet deep 42 inches around and tell the superintendent how many concrete trucks to order up.

Once those were poured, the ironworker would set to work in the big hexagon cofferdam-- about 40 feet across and do his rebar work. Then of course we'd again have to figure out how many concrete trucks to order in to fill this 15 foot deep 40 foot across hexagon
shaped hole in the ground.

 

it must be something in the water.

You can do two things,

Take a string and wrap it around the tire. Then mark off where they meet, then measure that.

Or

Just look it up.

I prefer the last thing myself.

By the way two other things.

Why would you need to measure them?

And what is an endless steel tape?