700c Vs. 27" Wheel Size: The Same?

"Aman" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hello,

Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? What does the c stand for
anyway?

Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.

Please e-mail me back personally, as well as the newsgroup.

Thanks for your time, Happy Trails, Alex

I think 27" wheels are slightly larger.

Aman said:

Hello,

Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? What does the c stand for
anyway?

Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.

Please e-mail me back personally, as well as the newsgroup.

Thanks for your time, Happy Trails, Alex

Dear Alex,

No, 27 & 1/4" rims and tires are a slightly different size
than 700c rims and tires--you can't swap them.

The c in 700c is not for centimeters, but for some sort of
rim width, as in a-b-c-d-e.

If you go to this site and start browsing the "bicycle
glossary" and searching for things, you'll waste an
astonishing amount of extremely enjoyable time:

www.sheldonbrown.com

Carl Fogel

Aman said:

Hello,

Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? What does the c stand for
anyway?

Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.

Please e-mail me back personally, as well as the newsgroup.

Thanks for your time, Happy Trails, Alex

Dear Alex,

I went back, just to see how long it would take to find the
answer to your size question, and was horrified to see that
"rim" fails to give an instant answer--I honestly don't know
why we pay Sheldon so lavishly to keep that site up and
running if it takes two stabs.

So here's a direct link:

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

The size question is answered by the fourth line of the
first table. For 700a-b-c, you have to go down to "French
sizes."

Carl Fogel

On Fri, 7 Jan 2005 17:35:55 -0800, "yum" <[email hidden]>

Quoted message said:

"Aman" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hello,

Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? What does the c stand for
anyway?

Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.

Please e-mail me back personally, as well as the newsgroup.

Thanks for your time, Happy Trails, Alex

I think 27" wheels are slightly larger.

Dear Yum,

There is some support for that theory, given that one rim is
630mm and the other 622mm:

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

Cautiously,

Carl Fogel

Carl Fogel said:

...
No, 27 & 1/4" rims and tires are a slightly different size
than 700c rims and tires--you can't swap them....

Clinchers of the two sizes are not interchangeable [1], but inner tubes
are [2]. Just like inner tubes, sew-up/tubular tires are the same for
either size.

[1] One might be able to get a ISO 630-mm (27"😉 tire inflated on an ISO
622-mm (700C) rim, but the risk of a blowout and/or rolling the tire off
the rim would be very high.
[2] Most are marked for both sizes, inner tube rubber being elastic
enough that the approximate 2.5 cm/1" difference in circumference is
inconsequential.

--
Tom Sherman - Near Rock Island

Tom Sherman said:

Carl Fogel said:

...
No, 27 & 1/4" rims and tires are a slightly different size
than 700c rims and tires--you can't swap them....

Clinchers of the two sizes are not interchangeable [1], but inner tubes
are [2]. Just like inner tubes, sew-up/tubular tires are the same for
either size.

Tubes are interchangeable given the amount of stretch they
have. But there are no 27" sew-up/tubular tires - they've only
been offered in the 700c size and would certainly not work on a
rim with an 8mm larger diameter.

Peter said:

Tubes are interchangeable given the amount of stretch they
have. But there are no 27" sew-up/tubular tires - they've only
been offered in the 700c size and would certainly not work on a
rim with an 8mm larger diameter.

You'd be surprised! Back in the day, I was out for a ride with a bunch
of friends and I flatted. Turned out that my tube had a bad valve and I
couldn't pump it up. I was riding 27" clinchers, the others in the
group were on tubulars. I borrowed a spare tubular from one of them and
managed to get it onto the 27" clincher rim with a bit of force.

It was quite secure, no danger of falling off, but it didn't protrude
all that far past the clincher rim, so I was a bit nervous riding back
home...but it was better than walking back from Gloucester!

Sheldon "Necessity Is A Mother" Brown
+-------------------------------------+
| Only those who attempt the absurd |
| will achieve the impossible. |
| --Albert Einstein |
+-------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Aman said:

(1) Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? (2)What does the c stand for
anyway?
(3) Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.
(4)Please e-mail me back personally, as well as the newsgroup.

As Mr Fogel might say:
www.google.com or Mr. Brown's informative site

(1)No, they are different sizes

(2)The earlier versions (700A,700B}were also roughly 700mm
diameter at the outside but with different bead seat diameters*.

(3) 700C brake shoes are 5~6mm lower than 27 inch.
The actual diameter is molded into the side of your tires.
27" are 630mm dia =1956mm circumference*
700C are 622mm dia =1978mm circumference*

*Bead seat diameter is the inside edge of your tire. That's
the same size as the lip on which your tire seats inside the
rim.

(4) No.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971,

A Muzi said:

Aman said:

(1) Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c? (2)What does the c stand for
anyway?
(3) Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.
(4)Please e-mail me back personally, as well as the newsgroup.

As Mr Fogel might say:
www.google.com or Mr. Brown's informative site

(1)No, they are different sizes

(2)The earlier versions (700A,700B}were also roughly 700mm
diameter at the outside but with different bead seat diameters*.

(3) 700C brake shoes are 5~6mm lower than 27 inch.
The actual diameter is molded into the side of your tires.
27" are 630mm dia =1956mm circumference*
700C are 622mm dia =1978mm circumference*

*Bead seat diameter is the inside edge of your tire. That's
the same size as the lip on which your tire seats inside the
rim.

(4) No.

Dear Andrew,

You're right and I'm wrong--the a-b-c is for bead seat
diameter, not rim width.

Slightly less ignorantly,

Carl Fogel

Sheldon Brown said:

Sheldon "Necessity Is A Mother" Brown

You invent that?

Sheldon Brown said:

Peter said:

Tubes are interchangeable given the amount of stretch they
have. But there are no 27" sew-up/tubular tires - they've only
been offered in the 700c size and would certainly not work on a
rim with an 8mm larger diameter.

You'd be surprised! Back in the day, I was out for a ride with a bunch
of friends and I flatted. Turned out that my tube had a bad valve and I
couldn't pump it up. I was riding 27" clinchers, the others in the
group were on tubulars. I borrowed a spare tubular from one of them and
managed to get it onto the 27" clincher rim with a bit of force.

No, that doesn't surprise me at all, but it's quite different from
getting that tubular onto a rim made for tubulars but with an 8 mm
larger diameter. Putting it on a 630 mm clincher rim lets the
tire drop down into the deeper channel and gives you about the same
effective diameter as the 622 mm tubular rim. I noticed a similar
effect when changing my tubular rims to clincher. If I switched to a
700c clincher rim the old spokes would have been too long, but by
switching to a 27" clincher rim the spokes could be reused. (And
at that time 27" clincher tires were easier to find than 700c -
not anymore.) The brake shoes had sufficient adjustment for either
size.

Quoted message said:

Carl Fogel said:

No, 27 & 1/4" rims and tires are a slightly different size
than 700c rims and tires--you can't swap them....

Tom Sherman said:

Clinchers of the two sizes are not interchangeable [1], but inner tubes
are [2]. Just like inner tubes, sew-up/tubular tires are the same for
either size.
[1] One might be able to get a ISO 630-mm (27"😉 tire inflated on an ISO
622-mm (700C) rim, but the risk of a blowout and/or rolling the tire off
the rim would be very high.
[2] Most are marked for both sizes, inner tube rubber being elastic
enough that the approximate 2.5 cm/1" difference in circumference is
inconsequential.

I understood your explanation of the tubes - tubes fit
interchangeably between these similar diameters as long as
the width is appropriate.

But you lost me on the tubulars.

The two clinchers 'wire-ons'😉 are 622mm and 630mm
respectively. Tubulars are just tubulars amd have been of
one universal diameter for a hundred years. However,
various manufacturers mark them 700, 27 and 28 inches
without logical explanation. A tubular brake surface is at
the same diameter as a 700C rin.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Quoted message said:

Aman wrote:

-snip-
27" wheels ? 700C wheels? Nomenclature?

(am)-snip-

Quoted message said:

Quoted message said:

(2)The earlier versions (700A,700B}were also roughly 700mm
diameter at the outside but with different bead seat diameters*.

[email hidden] wrote:
-snip-

the a-b-c is for bead seat

Quoted message said:

diameter, not rim width.

Right . It's an hysterical progression. Or was that historical?

There's an inexorable trend to miniaturization in tires ,
tubes, rims. 700 A, B, C ( and that evil, short-lived D)
are smaller with every iteration.

In our times, notice how much smaller a 27x1-1/4" (K2) tire
is compared to twenty years ago! The classic 26x1-1/8"
(EA3) has also been on a diet, being about 2/3 the width it
was in the seventies.

And inner tubes! Much skinnier in every 'size' every few
years or so.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

Quoted message said:

Carl Fogel said:

No, 27 & 1/4" rims and tires are a slightly different size
than 700c rims and tires--you can't swap them....

Tom Sherman said:

Clinchers of the two sizes are not interchangeable [1], but inner
tubes are [2]. Just like inner tubes, sew-up/tubular tires are the
same for either size.
[1] One might be able to get a ISO 630-mm (27"😉 tire inflated on an
ISO 622-mm (700C) rim, but the risk of a blowout and/or rolling the
tire off the rim would be very high.
[2] Most are marked for both sizes, inner tube rubber being elastic
enough that the approximate 2.5 cm/1" difference in circumference is
inconsequential.

I understood your explanation of the tubes - tubes fit interchangeably
between these similar diameters as long as the width is appropriate.

But you lost me on the tubulars.

The two clinchers 'wire-ons'😉 are 622mm and 630mm respectively.
Tubulars are just tubulars amd have been of one universal diameter for a
hundred years. However, various manufacturers mark them 700, 27 and 28
inches without logical explanation. A tubular brake surface is at the
same diameter as a 700C rin.

I should have stated it differently - tubulars are the same size (within
production, model, and manufacturer tolerances) whether or not they are
marked "27-inch" or "700C".

--
Tom Sherman - Near Rock Island

Aman said:

Hello,

Are 27" wheels, which I usually see on road bikes from
the 1970's, the same size as 700c?

No. They are close, but not the same; there's 8mm of difference in
diameter, which is enough that the tires can't safely be interchanged.

Quoted message said:

What does the c stand for
anyway?

It's a letter. The 700C rim is 622mm in diameter at the bead seat,
the 700B is 635mm, and the 700D is 587mm. Why are they all 700?
Because that's the approximate outside diameter of the wheel and tire
assembly as originally developed; from A through D, the idea was that
the tires would get wider...but what ended up happening was something
else entirely. 700B rims got used for European rod-brake roadsters
with relatively fat tires which made them larger than 700mm overall,
while 700C rims became the common size for racing-oriented bikes with
very narrow tires, and 700D basically fell out of usage.

Quoted message said:

Mainly what I want to know is one slightly bigger than
the other, and which is bigger? I'm talking diameter.

The rim for a 27" tire is slightly larger than the rim for a 700C.
Some frames which were originally set up for for 27" can be swapped
over to 700C successfully, some can't. It's a matter of brake reach.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Sheldon Brown said:

Peter said:

Tubes are interchangeable given the amount of stretch they
have. But there are no 27" sew-up/tubular tires - they've only
been offered in the 700c size and would certainly not work on a
rim with an 8mm larger diameter.

You'd be surprised! Back in the day, I was out for a ride with a bunch
of friends and I flatted. Turned out that my tube had a bad valve and I
couldn't pump it up. I was riding 27" clinchers, the others in the
group were on tubulars. I borrowed a spare tubular from one of them and
managed to get it onto the 27" clincher rim with a bit of force.

It was quite secure, no danger of falling off, but it didn't protrude
all that far past the clincher rim, so I was a bit nervous riding back
home...but it was better than walking back from Gloucester!

Sheldon "Necessity Is A Mother" Brown
+-------------------------------------+
| Only those who attempt the absurd |
| will achieve the impossible. |
| --Albert Einstein |
+-------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sew up tires are quite forgiving in what diameter rim they'll go on.
I've successfully used "700C" sew up tires on 650C rims. I just kept
inflating -- the tire got smaller and smaller!

I nicked:

Quoted message said:

Quoted message said:

Sheldon "Necessity Is A Mother" Brown

Bill Sornson asked:

Quoted message said:

You invent that?

Nope. Mighta been Jim Heaney, can't recall for sure.

Sheldon "Open Beer" Brown
+---------------------------------------------------+
| Originality is the fine art of remembering |
| what you hear but forgetting where you heard it. |
| -- Laurence Peter |
+---------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

A Muzi said:

In our times, notice how much smaller a 27x1-1/4" (K2) tire
is compared to twenty years ago! The classic 26x1-1/8"
(EA3) has also been on a diet, being about 2/3 the width it
was in the seventies.

And inner tubes! Much skinnier in every 'size' every few
years or so.

It's like candy bars- instead of raising the price, they just shrink
the product to keep costs down. Brings a whole new meaning to
"inflation".

Jeff

dianne_1234 said:

On Fri, 07 Jan 2005 23:06:18 -0500, Sheldon Brown

Quoted message said:

Peter said:

Tubes are interchangeable given the amount of stretch they
have. But there are no 27" sew-up/tubular tires - they've only
been offered in the 700c size and would certainly not work on a
rim with an 8mm larger diameter.

You'd be surprised! Back in the day, I was out for a ride with a bunch
of friends and I flatted. Turned out that my tube had a bad valve and I
couldn't pump it up. I was riding 27" clinchers, the others in the
group were on tubulars. I borrowed a spare tubular from one of them and
managed to get it onto the 27" clincher rim with a bit of force.

It was quite secure, no danger of falling off, but it didn't protrude
all that far past the clincher rim, so I was a bit nervous riding back
home...but it was better than walking back from Gloucester!

Sheldon "Necessity Is A Mother" Brown
+-------------------------------------+
| Only those who attempt the absurd |
| will achieve the impossible. |
| --Albert Einstein |
+-------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sew up tires are quite forgiving in what diameter rim they'll go on.
I've successfully used "700C" sew up tires on 650C rims. I just kept
inflating -- the tire got smaller and smaller!

How was performance with the 700C sew up on the 650C rim?

Was that a clincher rim?