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Old 09-21-07, 06:41 AM   #1
flameburns623
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How big are 700 CM tires?

Hello!

Someone should've aborted the idiot who created the Metric system. So how big are 700 centimeter tires? I get the impression they are about 27 inchese but my tape measure shows me that 27 inches is about 69 centimeters--27-and-a-half inches is about 70 centimeters, BUT that's still off by a factor of ten. Unless I'm looking at really old-fashioned bikes, with seats several feet from the ground, somehting isn't quite right. From the photos I'm seeing, these are normal-sized bikes. So what's up? One web search seemed as if it suggested 700 centimeters was the WIDTH of the tires, but that would make the tires several FEET wide. Also seems improbable to say the least.

You know, for all the purported virtues of 'simplicity' with the metric system, the traditional measurments are usually much simpler: they were based, roughly, on anatomical or other familiar comparisons, and most folks could use fingers, arms, feet, etcetera to guestimate the approximate size of other objects. (No crude jokes, please).
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Old 09-21-07, 06:48 AM   #2
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Check out this link. 700c tires are nowhere near 700 cm.

http://sheldonbrown.com/tire-sizing.html

Last edited by tellyho; 09-21-07 at 06:55 AM.
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Old 09-21-07, 06:51 AM   #3
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Drop the M from 700CM. They're 700c, as in a, b, c, etc. They get the "700" from the fact that the outside diameter of the tire is around 700mm. If you don't like to call them 700c, you can call them by their more logical ETRTO name, which gives a tire's width and bead seat diameter, in millimeters. For a 700 x 28c tire, for example, that would be 28-622.

Last edited by well biked; 09-21-07 at 06:56 AM.
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Old 09-21-07, 10:47 AM   #4
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Originally Posted by flameburns623 View Post
Someone should've aborted the idiot who created the Metric system.
No, but it's something we Americans have to learn about since the rest of the workld uses it. Actually, the "English" measurement system we still use makes no logical sense at all and, while the Metric system is not completely logical, it is a whole lot better.

And as noted, 700c is not a measurement in cm.
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Old 08-29-09, 12:40 PM   #5
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while the Metric system is not completely logical
What's not logical about the metric system? I am not fully accustomed to it myself, but the conversion between units is so much easier than the imperial system.
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Old 08-29-09, 07:02 PM   #6
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622mm, or 62.2cm, is what a common 700C is really. One would think that the 'C' would refer to a metric measurement. But how could it? If C = cm = centimeter, you would have a 700 centimeter rim. And that's 275.59 inches! You'd need a step-ladder!

If you'd like a neat little converter for all-things-metric into more familiar things like inches an psi, here is a free download for your computer. Totally free and no nifty bugs, either:

http://joshmadison.com/software/convert-for-windows/

Last edited by Panthers007; 08-29-09 at 07:05 PM.
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Old 08-29-09, 07:12 PM   #7
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The measurement is 700 MILLIMETERS.

Please, stop posting. You're reinforcing the negative dumb American stereotype.
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Old 08-29-09, 07:24 PM   #8
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The measurement is 700 MILLIMETERS.

Please, stop posting. You're reinforcing the negative dumb American stereotype.
The measurement is 622 MILLIMETERS.
Please, stop posting. You're reinforcing the negative dumb American stereotype.
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Old 08-29-09, 08:11 PM   #9
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The measurement is 700 MILLIMETERS.

Please, stop posting. You're reinforcing the negative dumb American stereotype.
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Old 08-29-09, 08:20 PM   #10
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Drop the M from 700CM. They're 700c, as in a, b, c, etc. They get the "700" from the fact that the outside diameter of the tire is around 700mm.
Correct answer. 700mm includes a tire. It became a standard back when road tires were typically larger.
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Old 08-29-09, 08:39 PM   #11
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What's not logical about the metric system? I am not fully accustomed to it myself, but the conversion between units is so much easier than the imperial system.
There are units that don't strictly follow the 10X, 100X, 1000X sequence like Angstroms and a few like Pascals that no one but a few scientists use but, as I said at first, the system is far more logical than the Imperial system we use here.

Actually we use both systems which is even more confusing. Soda comes in 2 liter bottles these days and booze in 750 ml, 1L and 1.75 L bottles. Metric bolts and other parts are common on "American" cars. We run 10K races. Etc.
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Old 08-29-09, 08:46 PM   #12
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I'll put the popcorn in the microwave!
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Old 08-29-09, 08:48 PM   #13
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Originally Posted by HillRider View Post
There are units that don't strictly follow the 10X, 100X, 1000X sequence like Angstroms and a few like Pascals that no one but a few scientists use but, as I said at first, the system is far more logical than the Imperial system we use here.

Actually we use both systems which is even more confusing. Soda comes in 2 liter bottles these days and booze in 750 ml, 1L and 1.75 L bottles. Metric bolts and other parts are common on "American" cars. We run 10K races. Etc.
Ya, you betcha. I work in a hospital pharmacy- for the most part, stuff comes in grams, milligrams, & micrograms. Some liquids still come in 1/2 quart (473ml) bottles. Every once in a while someone will ask for a grain (64.8mg) of something- at which point they're dragged outside and burned at the stake.
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Old 08-29-09, 08:53 PM   #14
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We may use metric bolts in cars and metric sockets to turn the bolts, but the backside of the sockets will still be 1/2, 3/8, or 1/4 inch.
Most bicycle parts are metric except chains and steer tubes.
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Old 08-29-09, 09:01 PM   #15
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We may use metric bolts in cars and metric sockets to turn the bolts, but the backside of the sockets will still be 1/2, 3/8, or 1/4 inch.
Most bicycle parts are metric except chains and steer tubes.
And bottom bracket threads.
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Old 08-29-09, 09:25 PM   #16
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We may use metric bolts in cars and metric sockets to turn the bolts, but the backside of the sockets will still be 1/2, 3/8, or 1/4 inch.
Right, but I believe that even in the most metric of countries, ratchets are still made with 1/4", 3/8" and 1/2" square drives even if used exclusively with metric sockets.

As noted, some ISO bike standards are Imperial measurements like English bottom brackets, threaded steerers and freewheel threads. Even Italian bottom brackets aren't pure metric, being 36 mm x 24TPI.
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Old 08-29-09, 10:19 PM   #17
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As a chemist and die-hard science-head, I started using metric when I was 10. It makes perfect sense. Here is one of my favorite stories about how logical metric is, and how ding-dong Imperial is:

An English man named Fahrenheit took a tube with a bit of mercury in it that was sealed in a vacuum. Into this tube he etched numbers from, say, 0 to 250. Then he placed the tube into ice-water. The water was frozen at the 32 on his tube. Then he slowly brought the water to a rolling-boil. His tube said 212. So he recorded that 32(F) was the freezing point of water, and water boiled at 212(F).

Meanwhile a guy across the channel took a tube with a bit of mercury in it and sealed it in a vacuum. His name was Celsius. And he placed this tube into frozen water. He THEN etched '0' into the glass on his tube. And then he brought the water to a rolling-boil. He marked this as 100(C).

I'll leave it right here.

Last edited by Panthers007; 08-29-09 at 11:04 PM. Reason: Sp.
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Old 08-29-09, 10:45 PM   #18
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Actually, there is quite a bit of imperial measure used in bikes. Pedals are 9/16-20 unless they are 1/2"-20 or french. 25.4mm handlebars are 1", seat posts are generally fractional inch sizes translated to mm, as are tubing sizes. One of the things that made french bikes weird was they were all metric.
Jeff, check your math. Down here we get 15.4 grains to the gram. I bet you meant milligrams.
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Old 08-29-09, 10:50 PM   #19
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Jeff, check your math. Down here we get 15.4 grains to the gram. I bet you meant milligrams.
You are correct! And I am over-caffeinated!!... like I said, I don't see grains much.

'Round here, we just say it's dope, yo.
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Old 08-29-09, 10:51 PM   #20
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Metric bolts and other parts are common on "American" cars. We run 10K races. Etc.
I used to have a 1989 Ford Taurus, and the first time I went to change the battery, I found that it had a metric bolt on one terminal and an SAE one on the other!
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Old 08-30-09, 03:00 AM   #21
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The measurement is 622 MILLIMETERS.
Please, stop posting. You're reinforcing the negative dumb American stereotype.
Well, stereotype or not, you've both gotten rule #1 of successfull quarreling down pat - it helps if you don't pay too much attention to what the opponent is actually saying...
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Old 08-30-09, 07:22 AM   #22
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Quote:
Originally Posted by Panthers007 View Post
An English man named Fahrenheit took a tube with a bit of mercury in it that was sealed in a vacuum. Into this tube he etched numbers from, say, 0 to 250. Then he placed the tube into ice-water. The water was frozen at the 32 on his tube. Then he slowly brought the water to a rolling-boil. His tube said 212. So he recorded that 32(F) was the freezing point of water, and water boiled at 212(F).
Well he did it in 1724 so give him a bit of slack. The 0 point was the coldest he could get at the time which was a saturated ammonium chloride brine and he likely thought it was the coldest temperature obtainable with anything. It had the benefit of avoiding negative numbers. The remaining numbers were chosen to make creating the scale on the thermometer easy using the crude ruling methods available to him.

Quote:
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Meanwhile a guy across the channel took a tube with a bit of mercury in it and sealed it in a vacuum. His name was Celsius. And he placed this tube into frozen water. He THEN etched '0' into the glass on his tube. And then he brought the water to a rolling-boil. He marked this as 100(C).
The guy across the channel was in Sweden and Anders Celsius actually created a scale with 0 as the boiling point of water and 100 as the freezing point. The scale was reversed to our common usage after his death.
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Old 08-30-09, 07:36 AM   #23
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I used to have a 1989 Ford Taurus, and the first time I went to change the battery, I found that it had a metric bolt on one terminal and an SAE one on the other!
I have a 1960 Volvo, the engine bolts are SAE and the bolts on the body are metric.
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Old 08-30-09, 07:46 AM   #24
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Tires are 700mm. Rims are 622mm. The question was about tires.

Now, stop posting.
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Old 08-30-09, 08:23 AM   #25
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Tires are 700mm. Rims are 622mm. The question was about tires.

Now, stop posting.
Tires of different widths have different diameters.
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