Strange tire marking
05-17-10, 08:32 PM
#1
What??? Only 2 wheels?
Thread Starter
Join Date: Apr 2010
Location: Boston-ish, MA
Posts: 13,434
Bikes: 72 Peugeot UO-8, 82 Peugeot TH8, 87 Bianchi Brava, 76? Masi Grand Criterium, 74 Motobecane Champion Team, 86 & 77 Gazelle champion mondial, 81? Grandis, 82? Tommasini, 83 Peugeot PF10
Mentioned: 189 Post(s)
Tagged: 0 Thread(s)
Quoted: 1222 Post(s)
Liked 645 Times
in
232 Posts
Strange tire marking
I'm posting this to C&V instead of Bike Mechanics because it is more a reflection of how things were a few decades ago.
Today I replaced some old tires. The one on the front was a Specialized, marked 1-1/8", 110psi. It was noticeably narrower than the Pasela TG 1-1/8" I had put on the slightly narrower rear wheel. Okay, so that just shows that tires can be different even with the same markings.
But then I noticed that embossed on the sidewall was 23-630. Huh? No, it was not a 28 smudged out to form 23. I looked again. It was definitely 23. So what is it supposed to be, I asked myself? Wider than an inch or narrower? When inflated the sidewalls measured about 27mm, what I would have expected.
Curious.
Today I replaced some old tires. The one on the front was a Specialized, marked 1-1/8", 110psi. It was noticeably narrower than the Pasela TG 1-1/8" I had put on the slightly narrower rear wheel. Okay, so that just shows that tires can be different even with the same markings.
But then I noticed that embossed on the sidewall was 23-630. Huh? No, it was not a 28 smudged out to form 23. I looked again. It was definitely 23. So what is it supposed to be, I asked myself? Wider than an inch or narrower? When inflated the sidewalls measured about 27mm, what I would have expected.
Curious.
__________________
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
05-17-10, 08:41 PM
#2
www.theheadbadge.com
Join Date: Sep 2005
Location: Southern Florida
Posts: 28,512
Bikes: https://www.theheadbadge.com
Mentioned: 124 Post(s)
Tagged: 0 Thread(s)
Quoted: 2421 Post(s)
Liked 4,387 Times
in
2,092 Posts
Panaracer sizes relatively truthfully; everyone else simply makes their casings smaller. A Pasela is almost always equal to the next size down in reference to the 27" tires:
27x1" = everyone else's 27x1-1/8"
27x1-1/8" = everyone else's 27x1-1/4"
27x1-1/4" = everyone else's 27x1-3/4"
-Kurt
27x1" = everyone else's 27x1-1/8"
27x1-1/8" = everyone else's 27x1-1/4"
27x1-1/4" = everyone else's 27x1-3/4"
-Kurt
__________________
05-17-10, 08:48 PM
#3
What??? Only 2 wheels?
Thread Starter
Join Date: Apr 2010
Location: Boston-ish, MA
Posts: 13,434
Bikes: 72 Peugeot UO-8, 82 Peugeot TH8, 87 Bianchi Brava, 76? Masi Grand Criterium, 74 Motobecane Champion Team, 86 & 77 Gazelle champion mondial, 81? Grandis, 82? Tommasini, 83 Peugeot PF10
Mentioned: 189 Post(s)
Tagged: 0 Thread(s)
Quoted: 1222 Post(s)
Liked 645 Times
in
232 Posts
Yeah, but... The curiosity was not the real size but the contradictory markings. The multi-colored label was correct, more or less. The number embossed in the sidewall wasn't even close. Given that Specialized was one of the first companies to come out with high-pressure narrow clinchers (as far as I remember it) I won't blame them for being aggressive with the specs. But you'd've thought they could be more consistent.
__________________
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
05-17-10, 08:48 PM
#4
Señor Member
Join Date: Oct 2004
Location: Hardy, VA
Posts: 17,923
Bikes: Mostly English - predominantly Raleighs
Mentioned: 70 Post(s)
Tagged: 0 Thread(s)
Quoted: 1491 Post(s)
Liked 1,090 Times
in
638 Posts
Are you measuring 27mm side to side, or bead to top?
__________________
In search of what to search for.
In search of what to search for.
05-17-10, 08:58 PM
#5
aka Tom Reingold
Join Date: Jan 2009
Location: New York, NY, and High Falls, NY, USA
Posts: 40,502
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
Mentioned: 511 Post(s)
Tagged: 0 Thread(s)
Quoted: 7348 Post(s)
Liked 2,460 Times
in
1,432 Posts
Perhaps the 1-1/8" marking means that's the approximate inflated width on whatever rim they expect you to use. The ETRTO size (23-630) is measured a specific way. They didn't measure the actual inflated width. They measured the linear distance between the beads of the tire (when flattened out) and divided by 2.5.
__________________
Tom Reingold, tom@noglider.com
New York City and High Falls, NY
Blogs: The Experienced Cyclist; noglider's ride blog
“When man invented the bicycle he reached the peak of his attainments.” — Elizabeth West, US author
Please email me rather than PM'ing me. Thanks.
Tom Reingold, tom@noglider.com
New York City and High Falls, NY
Blogs: The Experienced Cyclist; noglider's ride blog
“When man invented the bicycle he reached the peak of his attainments.” — Elizabeth West, US author
Please email me rather than PM'ing me. Thanks.
05-17-10, 09:47 PM
#6
What??? Only 2 wheels?
Thread Starter
Join Date: Apr 2010
Location: Boston-ish, MA
Posts: 13,434
Bikes: 72 Peugeot UO-8, 82 Peugeot TH8, 87 Bianchi Brava, 76? Masi Grand Criterium, 74 Motobecane Champion Team, 86 & 77 Gazelle champion mondial, 81? Grandis, 82? Tommasini, 83 Peugeot PF10
Mentioned: 189 Post(s)
Tagged: 0 Thread(s)
Quoted: 1222 Post(s)
Liked 645 Times
in
232 Posts
That was measured outside sidewall to sidewall with a caliper. It is of course approximate. I wasn't trying to match marking to actual size. I measured it only because it was visibly smaller than the 1-1/8" Pasela on the rear, so I wanted to compare them to check my perception. I didn't notice the contradictory markings until days later.
__________________
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
05-17-10, 10:01 PM
#7
curmudgineer
Join Date: Dec 2009
Location: Chicago SW burbs
Posts: 4,417
Bikes: 2 many 2 fit here
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 263 Post(s)
Liked 112 Times
in
70 Posts
Panaracer sizes relatively truthfully; everyone else simply makes their casings smaller. A Pasela is almost always equal to the next size down in reference to the 27" tires:
27x1" = everyone else's 27x1-1/8"
27x1-1/8" = everyone else's 27x1-1/4"
27x1-1/4" = everyone else's 27x1-3/4"
-Kurt
27x1" = everyone else's 27x1-1/8"
27x1-1/8" = everyone else's 27x1-1/4"
27x1-1/4" = everyone else's 27x1-3/4"
-Kurt
05-18-10, 06:48 AM
#8
multimodal commuter
Join Date: Nov 2006
Location: NJ, NYC, LI
Posts: 19,808
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
Mentioned: 584 Post(s)
Tagged: 0 Thread(s)
Quoted: 1908 Post(s)
Liked 574 Times
in
339 Posts
For what it's worth, I have a pair of Michelin tires that are labeled both 27 x 1 and 27 x 1 1/8.
Oh, and I have one, I think it's a Continental, that's labeled both 700 x 28 and 27 x 1 1/8, but that's just an obvious ****-up (it's a 700c tire).
Oh, and I have one, I think it's a Continental, that's labeled both 700 x 28 and 27 x 1 1/8, but that's just an obvious ****-up (it's a 700c tire).
05-18-10, 07:52 AM
#9
Senior Member
Join Date: Jul 2006
Location: Toronto (again) Ontario, Canada
Posts: 6,931
Bikes: Old Bike: 1975 Raleigh Delta, New Bike: 2004 Norco Bushpilot
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 5 Times
in
5 Posts
I'm posting this to C&V instead of Bike Mechanics because it is more a reflection of how things were a few decades ago.
Today I replaced some old tires. The one on the front was a Specialized, marked 1-1/8", 110psi. It was noticeably narrower than the Pasela TG 1-1/8" I had put on the slightly narrower rear wheel. Okay, so that just shows that tires can be different even with the same markings.
But then I noticed that embossed on the sidewall was 23-630. Huh? No, it was not a 28 smudged out to form 23. I looked again. It was definitely 23. So what is it supposed to be, I asked myself? Wider than an inch or narrower? When inflated the sidewalls measured about 27mm, what I would have expected.
Curious.
Today I replaced some old tires. The one on the front was a Specialized, marked 1-1/8", 110psi. It was noticeably narrower than the Pasela TG 1-1/8" I had put on the slightly narrower rear wheel. Okay, so that just shows that tires can be different even with the same markings.
But then I noticed that embossed on the sidewall was 23-630. Huh? No, it was not a 28 smudged out to form 23. I looked again. It was definitely 23. So what is it supposed to be, I asked myself? Wider than an inch or narrower? When inflated the sidewalls measured about 27mm, what I would have expected.
Curious.
23-630 would be the ISO tire size, the inner width of the rim is 23mm and the bead seat diameter of the rim is 630mm. ISO tire sizes are based on the size of the rim the tire fits, not the physical size of the tire, which would be about right for a 27" x 1¼" inch tire. Newer tires should have both marked on them, which the tires you have probably are.
Sheldon Brown says more here
