Favorit hub and 35 PSI tire

[Emanuel Berg]

Today was yet another bike that looks like
every other, a 26" Crescent open-frame from the
70s or 80s.

I removed the rear wheel and noticed the
familiar Torpedo single speed hub. Only there
was something unfamiliar to it. Turns out, it
is a Czechoslovakian Favorit! And it appears
this was of no less quality than the Torpedos
and SAs because it looks very good.

Even the tire is of the original package, it
reads "Made in Czechoslovakia" which was
dissolved in 1993.

The tire, Barum, is also of good quality with
all the markings, the ISO or ETRTO 44-584 as
well as all three inch sizes,
26 x 1 1/2 x 1 5/8. It also says T15/V10 (?).

Last thing it says is somewhat of a surprise:
"Inflate to 35 PSI - 250 kPa". Only 35?

To compare, without having to look for another
44-584, I checked out the front wheel tire of
the same bike. This is a 40-609 with a familiar
50 PSI or 350 kPa.

Actually, I always thought those data too high.
The tire gets super tight. So perhaps 35 is
more reasonable even tho compared to what is
usually there, much lower?

--
underground experts united
http://user.it.uu.se/~embe8573

[Emanuel Berg]

I just now put in ~35 PSI and it is stiff
enough. Perhaps that smaller BSD played a trick
on me? One should compute the volume to find
out if it really is less preassure...

[AMuzi]

-609 tire? WTF? Did you mean -590??

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

[Emanuel Berg]

AMuzi wrote:

> -609 tire? WTF? Did you mean -590??

Shinko Golden Boy

40-609 or 27 x 1 1/2

50 psi or 350 kPa

Made in Korea.

There is no queen of tires?

[Emanuel Berg]

Actually, now that I think about it the 27" or
609 wheel looks much better. It is probably
a 27" bike!

The 26" or 584 wheel is too small so it got its
way there later, I think.

And it makes sense politically as well because
pompous old Crescent probably wouldn't do with
Eastern bloc industrial imitations...

[Emanuel Berg]

AMuzi wrote:

> -609 tire? WTF? Did you mean -590??

... now I'm uncertain. When you said it it
sounded like you thought it was a strange tire
size. But maybe you thought it was strange
because it was so different from the other tire
(rear 584, front 609)?

Because I just went downstairs and looked for
27" rear wheels, and only looking at those who
had tires, I found no less than four 27"s, all
40-609 or 27 x 1 1/2.

They were all Torpedoes: one single speed, two
three speeds, and one duomatic.

[Emanuel Berg]

Today I found an inner tube that fits according
to the ISO mark, and is close enough to the
inch mark - it fails on the diameter tho
(tire 27, tube 28) which is the most
important one.

And the ISO interval is wide indeed.

But should be fine, for sure.

Here is what it says on the box:

CST (Cheng Shin Tire) 700C

28 x 1 5/8 x 1 3/8

37/47-609/642

It has a 40 mm Dunlop valve.

The 700 is the old French system or outer
diameter (diameter including tire), right?
But what does the "C" mean?

[Emanuel Berg]

On the old tube, Made in Taiwan, are three
markings, the most prominent being exactly

27 * 1 1/2 (40-609)

There is also two others:

27 * 1 3/8 (37-630)
27 * 1 3/8 * 1 1/2 (37-609)

Does this mean the tube is 40-609 but will work
for 37-630 and 37-609 as well? But why not
-622 then?

[AMuzi]

On 6/20/2017 8:18 AM, Emanuel Berg wrote:
> Today I found an inner tube that fits according
> to the ISO mark, and is close enough to the
> inch mark - it fails on the diameter tho
> (tire 27, tube 28) which is the most
> important one.
>
> And the ISO interval is wide indeed.
>
> But should be fine, for sure.
>
> Here is what it says on the box:
>
> CST (Cheng Shin Tire) 700C
>
> 28 x 1 5/8 x 1 3/8
>
> 37/47-609/642
>
> It has a 40 mm Dunlop valve.
>
> The 700 is the old French system or outer
> diameter (diameter including tire), right?
> But what does the "C" mean?
>

'700' originally were large at 642mm, later referred to as
700A. The revised format 700B got smaller (625? can't
recall), the current 700C smaller yet at 622m. (700D 587mm
utterly failed in the late 1980s)

[Emanuel Berg]

AMuzi wrote:

> '700' originally were large at 642mm, later
> referred to as 700A. The revised format 700B
> got smaller (625? can't recall), the current
> 700C smaller yet at 622m. (700D 587mm utterly
> failed in the late 1980s)

Aha, cool!

Because I take it the rim walls and tires
didn't get correspondingly higher I suppose the
700 just stuck as a designation and doesn't
mean 700 mm anymore...

Or does it? Because one unmounted 42-622 tire
that I have here seems to be pretty damn close
to 70 cm!

[Emanuel Berg]

I found the 609! at

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

It says:

609 mm Rare Dutch size, 27 x 1 1/2

I wonder why I have so many of the 609s.
Either they are not so rare, or they are, which
is the reason people dump them here...

[Emanuel Berg]

Returning to the psi, on the 42-622 I just
mentioned, it says inflate to

50-75 psi
340-515 kPa
3.4-5.1 bar

Some distance to the "35 psi" of the 40-609..

The 42-622 is an "Innova Flatfigher". It has
a 29 tpi, 3.5 mm nylon layer to protect against
the flat tire. Shouldn't matter to this
discussion, I guess...

Otherwise it says 700 * 40 C which is
consistent with what you say (700C being 622
mm) but inconsistent with the ISO 42 mm
width...

[Frank Krygowski]

I thought the original logic (if you can call it that) was that all 700
tires would have an outside diameter (tire+wheel) of 700 mm, but for
narrow tires (700A) the rim would have to be larger diameter to produce
the same outside diameter. If the tire was wide (700C) the rim would be
smaller diameter. So the 700C specification was originally intended for
wide tires.

But marketing and fashion are even less logical, so people began
demanding narrow tires to fit the smaller diameter and lighter 700C
rims. Those came to dominate, and 700A and 700B went away.

Is my history correct?

--
- Frank Krygowski

[Emanuel Berg]

Frank Krygowski wrote:

> I thought the original logic (if you can call
> it that) was that all 700 tires would have an
> outside diameter (tire+wheel) of 700 mm, but
> for narrow tires (700A) the rim would have to
> be larger diameter to produce the same
> outside diameter. If the tire was wide (700C)
> the rim would be smaller diameter. So the
> 700C specification was originally intended
> for wide tires.

Yeah, but if A to C are narrow to wide, what is
the other digit? The 42-622 I have is 700
x 40C. Did it once just say "700C", but when
the "C" didn't mean width anymore but rather
hinted at 622, they felt the need to specify 40,
only they kept the C to still hint at 622?
Perhaps they didn't use 622 explicitly at that
point but you get my meaning...

[Sir Ridesalot]

Try reading this:

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

Look at the chart third down from the top:
---------------------------------------------------

French Sizes:


700 A

642 mm

Obsolete



700 B

635 mm

Rod-brake roadsters.



700 C

622 mm

Road bikes, hybrids, "29 inch" MTBs.
(28 x 1 1/2 F.13 Canada)



700 D

587 mm

Oddball size formerly used on some GT models.
------------------------------------------------

Lots more information here.

Cheers