This came up in another thread. Well, not exactly - but I've wondered about it.

I've heard that this happened as people said that the 700c diameter wheel offered better performance of some kind, but it sounds like a lot of crap to me. I've never felt "faster" when riding 27", 700c, or 26" even. It just seems to depend upon all the other factors than influence speed.

I know that wheel diameter should be proportional to height, etc.

Did they just move to 700c so everyone would have to buy bike shop tires at high prices?

It was all just so we could use measurements in mm's so we sounded cooler.

It was a bit of trickle down from the high end bikes. 27" was a USA standard, but better bikes from Europe were all 700c, which has the virtue of being the same diameter as a tubular (sewup) tire's rim.

So for top end bikes where builders wanted interchangeability between wired on and tubulars going 700c made sense. Also there was a larger market for high end 700c tires supporting a bigger selection. In the end, starting at the top, and working all the way down to the low end, we simply went with the flow.

There was also a benefit to the major USA OEMs like Trek who were now selling their Taiwan made bikes in Europe. Using the same size rims in both markets made too much sense to pass up.

Interestingly enough when I brought 2 bikes to Mexico, I was very confident that I'd have no problems getting 700c tires. Not so, they're still using our cast off 27" standard. (go figure)

Consider yourself lucky. Remember when we tried to convert completely to metric in our school systems here in the US? It was called "New Math". Forget that the rest of entire world had been on the metric system. Anyway, it was a disaster. The teachers didn't even know how to teach it and the attempt only lasted a couple of years before we just gave up.

It's funny, anyone that knows what "new math" is here I can automatically guess their age within a few years.

In the U.S., the mainstream move from 27" clinchers to 700c clinchers occurred in the mid to late '80's. Big improvements were made in mainstream clincher rims/tires at that time as well, with hook edged rims hitting the mainstream being the biggest advancement. True racing rims/tires had been 700c all along, in the form of tubulars.

I think a lot of it was marketing......clinchers became more high performance (high pressure tires on hook edged rims available in the mainstream), and therefore a little closer to a tubular in regard to performance. Marketing, but 700c equated to racing tires, clincher tires/rims improved, so the switch was meant to associate the improved clincher tires/rims to the 700c racing tires.

Started in the early '80's, finished by the late '80's. I was working in a shop in the early '80's, and we started stocking all of the high-end tires in both 27" and 700C. We were careful not to mix them- putting a 27" tire on a 700C rim was a sure-fire way to create an ear-splitting blowout.

Man, those Schwinn Super Record yellow-label tires sure were light.

New Math had nothing at all to do with the metric system. It was set theory and venn diagrams and all that silliness.

Agreed that it had nothing to do with metric measurements but New Math was indeed Real Math.

So people could write in Craigslist..."27" bike for sale, like new condition" whic only illustrated that they hadn't a clue about sizing a bike. If they didn would have noted that had a 22, 23, or 24" frame as they were sized back then

I remember this time very well. I was in grade school and junior high at the time (the '70's). I thought the Metric system was something new and exciting for me and I was very disappointed when ignorant Americans were simply too lazy, in my opinion, to change. This was, and still is, a national embarrassment.

I am embarrassed that I am unable to find a metric tape measure in any of our local home improvement centers. What would I use it for? ummm...............how about measuring tire roll-out in mm's?

Pros still prefer Tubular , aka sewups, the rim is at 622 for the brake shoe's rim track,
so making clincher wire bead tires interchangeable on a race style bike with Tubolari
is a logical progression.

Metric system is so Napoleonic.

There is really no good reason the switch occured.

There is a bad reason of course.

Industry realized that there is not a lot of profit in steel bikes because they last a long time and people loved them. They started making aluminum and then carbon frames that gave no significant or meaningful advantage to the cycling world. Moving away from quality and longevity into a more disposable market which consequently made more profit. That was the end of the road for the 27'(630) wheel.

Sad but true.

On a side note.
If you are into numerology, you'll notice that both 27' or 630 mm make #9.(2+7=9 or 6+3+0=9). Also, If you keep adding 9's you'll always get a 9. For example 9+9=18(1+8=9) 18+18=36(3+6=9) 36+36=72,,,, and it goes on like that forever. This is not possible with any other number. Talk about a perfect circle. The sacred geometry. 360 degrees.

Lemmyguess, a progressive?

OK, we have some pretty good answers for how 700c became popular, but explaining why 27" has almost completely gone extinct requires a little more.

The high end roadies wanted 700c because of the tubular/Euro bike connection, but the low end buyers didn't really care. Then MOUNTAIN BIKES became the standard low-end purchase and there essentially WERE no low end road bikes in the shops and no 27" wheels. The only people buying road bikes were the high end folks.

Then road biking became popular again and people started buying entry level road bikes and the makers saw no reason to spec 27" wheels.

Very good reasons - thanks! That actually makes some sense.

Next question: When people say that you should ride 700c vs. 26" because they roll "a lot faster" why don't they also demand that we go from 700c to 27" for the same reason?

Because the change from 559 to 622 is big enough to make a noticeable difference(although not a huge one if tires/gearing are comparable) while the change from 622 to 630 is too small to be used for anything but argumentation and brake reach issues.

Good point.

It's just interesting that people use this as argument, when we used to be riding wheels that are even larger than 700c! (even if just by a tiny bit).

Good posts.

And yet even in 2010 it's possible to find a 27 x 1 1/4 tire in more places in the USA than 700C (x 19, 20, 22, 23, 25, 28, 30, 32, 35, 37, 38, 40, 42, 47, 50, 54, 57, 60 or 62).

Two folks on a cross country tour roll into a dusty little town, one on 700c tires and one riding obsolete 27"ers. They go into the hardware store. One comes out with a new tire. It'll be a 27 x 1 1/4!

In the UK 700C tires were sometimes known as "continental 27s".

In Germany what Norte-americanos call 27" tires are sometimes called 28".

If you are that enthralled with metric measurements, just refer to your 27" rims as ISO 630.

A major reason for the switch was that by the 70's the US was the only user of 27" wheels and the rest of the world had settled on 700C as it's standard road bike wheel size. European makers importing bikes here weren't going to change all of their frame and fork dimensions to accept 27" wheels so 700C got a foothold here as the size that defined a "good" bike.

My '85 Bridgestone 400 came with 27" wheels and was next to the bottom of their road bike line that year. The model above it, the 500, came with 700C wheels.

Maybe you can also ask why bicycles use metric fasteners instead of SAE. What's the matter with 10-32 bolts instead of M5x.8 or why should we need a 9mm wrench instead of 3/8"?

I'm all for proportional wheels.

700c for riders taller than 5'9
650c for riders taller than 5'6
26" for riders taller than 5'3

big wheels are harder to fit into frames, compared to smaller ones.
In fact, someone ought to make 750c (ISO 700) for riders over 6'0"

This is a mis-application of a traditional sizing standard.

Back in the 1920s-1960s there was very little adult cycling in the USA. Most bikes were sold at hardware and automotive tire stores for adolescents. The (upright riding position) bikes were sized by tire sizes: 16", 20", 24", 26".

Bikes at some big box stores are still sized in this way in 2010.

I received my metric tape measure as an industry gift from Russian counterparts. I use it almost every day to set seat heights, etc.

In the 70s quality bikes started coming out of Japan. They never used either 27" or 700c as a major standard for their home market & still don't. The Japanese manufacturers of the day - like today's Taiwanese manufacturers - would put any size wheel and tire on the bikes your contract called for.