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Dose anybody have any idea why (road) bikes are measured mostly in metric, but a few things (e.g. steerer size) are standard?

I know it reallyu does'nt matter, but this has been bugging me.

Thanks!
 

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dr pabst said:
Dose anybody have any idea why (road) bikes are measured mostly in metric, but a few things (e.g. steerer size) are standard?
Actually, the metric system is the world standard, with only three countries the last hold-outs: Liberia, Miyanmar and the U.S.A. At least we're in select company . . . :D

To answer your question: it's mostly tradition. Even countries that adopted the metric system in the 1800s used (or still use) non-metric units for some measurements. For example, 26" and 28" bicycle tire designation were still used in many European countries until just a few years ago.
 

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It's history

The bicycle as we know it was mainly invented in France (which was where the metric system was born), but the first companies to mass-produce bicycles and really start standardizing parts were in England (think Raleigh, etc.). In that period of early standardization (roughly 1890-1920), England was not using the metric system, so the English manufacturers used inch measurements for interchangeable parts (e.g., pedal threads are 9/16" x 20 tpi). These became the de facto industry standards, and some of them are still around.

Tire size designations are a whole other historical weirdness.
 

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... interestingly enuff, if I'm not mistaken, most modern bicycle chains and their related cogs and chainrings are still considered 1" pitch... as opposed to some metric measure... course, their thickness is metric...
 

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Metric is simply better. Why deal with fractions and all that when you can just get solid numbers. without metric a bike frames sizing availability would look like 18 9/10, 19 68/100, 20 1/2, 21 1/4, 22 4/100, 22 8/10, 23 6/10. Isnt it easier to just say 48,50,52,54,56,58,60?
 

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Akirasho said:
... interestingly enuff, if I'm not mistaken, most modern bicycle chains and their related cogs and chainrings are still considered 1" pitch... as opposed to some metric measure... course, their thickness is metric...
Some of these inch measurements probably will be with us forever. It makes the jargon more interesting and identifies outsiders if they get it wrong.

Take the way the height of horses is measured in the U.S: the unit is "hand". A good-size horse is 16 hands, for example. There are four inches in a hand, so you could have a 15.1, 15.2 and 15.3 hands horse, with the 0.1 = 1 inch. But if you ever say the word "point", the noob buzzer goes off—"15.1" is said "fifteen-one." And if you say or write "15.4 hands", you're done for—it doesn't exist because that would be 16 hands. :D
 

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absolutely true

Akirasho said:
... interestingly enuff, if I'm not mistaken, most modern bicycle chains and their related cogs and chainrings are still considered 1" pitch... as opposed to some metric measure... course, their thickness is metric...
chains are indeed 1-inch pitch, just as steerer tubes are 1-inch, or 1 1/8 inch, and a lot of thread dimensions are defined in inches. Of course, you could specify the same dimension in metric terms -- the chain has a pitch of 25.4mm ("English" units are now legally defined in terms of their metric equivalents -- an inch is exactly 25.4mm. Metric length units are defined in terms of quantities in nature that can be repeatably measured, assuming you have the technical skill and equipment. A meter is the distance light travels in a vacuum in 1/299,792,458 of a second.)
 

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B15serv said:
Metric is simply better. Why deal with fractions and all that when you can just get solid numbers. without metric a bike frames sizing availability would look like 18 9/10, 19 68/100, 20 1/2, 21 1/4, 22 4/100, 22 8/10, 23 6/10. Isnt it easier to just say 48,50,52,54,56,58,60?
Depends on the direction of conversion and the measurement. "Inch" bikes were simply sized whole units rather than skipping as metrics, which was close enough.

Meanwhile, you can feel all smart and modern because your bike has 31.7 or 31.8 bars, but they're both really the same size: 1-1/4. The difference depends on who's marketing department was doing the math. (And trust me on this: You should be very, very afraid when the marketing department breaks out calculators.)

We have 1-1/8" headsets because 1" is a historical, pre-Metric standard, and the 1-1/8 is an American 'innovation' (this time around, at least,) Not much benefit to changing to the 28.575 mm standard, though some have argued that they're faster, stiffer, and lighter.
 
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