# 27" X 1-1/4" VS 70 CM (27-1/2")



## borgward (May 4, 2022)

The tire on my Late 80's World Sport shows that it is 27" X 1-1/4". Looking for innertube, I see 700C which is 27-1/2". Is 27" the nominal size which is actually 27-1/2", or are 27" and 700C (27-1/2") tires and tubes different animals? If different, will 700C innertube work on my bike?


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## Schwinny (May 6, 2022)

27" and 700c take the same tube
Your tires will take a 700c 23-28 width for road bikes
27.5 is actually a crazy mix of a 650b diameter rim (584?) and a large tire so the tube is much bigger round for a much taller tire.
in real world application, a 700cx28 and a 27x1-1/4 are exactly the same in overall height. They take the same tube and most tube boxes will have both tire sizes on them.

I have found that the cheapest "bike world" tubes at Walmart are CST (Chinese) tubes and are of a good quality. I seem to always have issues with Kenda tubes.


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## borgward (May 6, 2022)

Walmart has a lot of tubes and tires now. Last year I had to order tires and tubes for my Raleigh 3 Speed. Are the peel and stick patches any good? Decades ago all I ever did was glue on or vulcanize patches.


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## borgward (May 11, 2022)

Schwinny said:


> 27" and 700c take the same tube
> Your tires will take a 700c 23-28 width for road bikes
> 27.5 is actually a crazy mix of a 650b diameter rim (584?) and a large tire so the tube is much bigger round for a much taller tire.
> in real world application, a 700cx28 and a 27x1-1/4 are exactly the same in overall height. They take the same tube and most tube boxes will have both tire sizes on them.
> ...



Now I need tires what is the equivalent for 27 X 1-1/4 tire. When I search for 27 X 1-1/4 tire all I get is 700C X ...


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## 3-speeder (May 11, 2022)

Shouldn't have any problems finding a variety of 27 inch tires.  The Panaracer Paselas are top notch.








						27 inch Tires
					






					www.modernbike.com


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## GTs58 (May 11, 2022)

When I search for 27 X 1-1/4 tires that's all I get.


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## borgward (May 11, 2022)

3-speeder said:


> Shouldn't have any problems finding a variety of 27 inch tires.  The Panaracer Paselas are top notch.
> 
> 
> 
> ...



That's what's on it now. That's what I will order. Funny,the other day I searched Amazon for 27 X 1 - 1/4 all I got was 27-1/2 and 700C. Today Amazon came up with 27 X 1 - 1/4. Go figure.


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## Schwinny (May 11, 2022)

27x1-1/4 is ISO 630/ 28
 Maybe try that


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## Arnold Ziffel (May 12, 2022)

27 x 1 1/4   is  (32-630)
1  1/4 inches  is  equal to  31.75 millimeters.
Now, different manufacturers' offerings of (32-630) 27 x 1 1/4 tires  DO IN FACT VARY, and significantly sometimes as to the actual tread width, even though the sidewall marking says (32-630).   Back in the day, the various manufacturers' tire offerings were nearly all close to the actual 32mm as marked (true to size), but not so today.  It depends on the tire model and from what particular manufacturer.   Some are true to size  and there are a few that are as much as 3.5mm undersized in width, though marked as 32-630.

27" has bead seat diameter of 630mm     (thus the 27" wheel is LARGER than the 700C  which has a BSD of 622mm)

700C  has  bead seat diameter  of 622mm

You generally  can  swap and interchange the 700C innertubes IF the tube's width size is compareable and wide enough  because the rubber stretch properties have no trouble with the 8mm difference in bead seat diameter.
Obviously the tires cannot interchange!









						The Bikesmiths
					

=Available in Gumwall or Blackwall. Choose from Single, 2-Pack, 4-Pack, 6-Pack or 10-Pack Size: 27x1-1/4" Bead: Wire Width: 32 ISO 630 Weight: 542g Choose from Blackwall or Gumwall tire The Kenda gumwall is a great high-pressure replacement road tire for your 27" wheels. Easy rolling tread...




					www.thebikesmiths.com
				












						The Bikesmiths
					

=Available in Gumwall or Blackwall. Choose from Single, 2-Pack, 4-Pack, 6-Pack or 10-Pack Size: 27x1-1/4" Bead: Wire Width: 32 ISO 630 Weight: 542g Choose from Blackwall or Gumwall tire The Kenda gumwall is a great high-pressure replacement road tire for your 27" wheels. Easy rolling tread...




					www.thebikesmiths.com


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## Archie Sturmer (May 13, 2022)

So the 700 is not centimeters or millimeters, although 700mm would equate to about ~27.5 something inches.
The 622mm dimension might be used for 700c wheels, which might fit either 28” or 29” tires.
Older 27” rims like on 10-speeds are 630mm.

Some tubes are sold by the range of tires that they might fit (like as marked on the box), but some sellers only state one of those sizes.

Recently, the last 27” x 1+1/4” tubes that I purchased were marked on the box to also fit other sizes (e.g., 700-something).  I believe that the markings, molded into the tubes, indicated a metric size.


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## Schwinny (May 13, 2022)

Archie Sturmer said:


> So the 700 is not centimeters or millimeters, although 700mm would equate to about ~27.5 something inches.
> The 622mm dimension might be used for 700c wheels, which might fit either 28” or 29” tires.
> Older 27” rims like on 10-speeds are 630mm.
> 
> ...



It is true 700mm is 27" +/- but I think it's all to confuse us and is doing a pretty good job.
I try to stick with ISO size then knowing 27.5 and 29r are to be avoided in my life.
I hope I don't get an itch for an old 28" tire bike.
Uhg


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## borgward (May 13, 2022)

3-speeder said:


> Shouldn't have any problems finding a variety of 27 inch tires.  The Panaracer Paselas are top notch.
> 
> 
> 
> ...



I got to a bike shop in Austin TX today. Got a tube. They have Vittoria tires. Any good? Bike has worn out Panaracer Paselas on it now. Our Bastrop County roads are in poor shape since the big chill in 2020. I ride for light exercise and enjoyment. Wondering if the Panaracers are a good choice for our roads?


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## 3-speeder (May 13, 2022)

You would get good advise on this from fellow Texan @bulldog1935


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## bulldog1935 (May 13, 2022)

Panaracer Paselas are the best 27" tire made.  (ISO 630)
Andy at Modern Bike has Paselas - I would say do not pass go.








						Panaracer  27 inch Tires
					






					www.modernbike.com
				



Note the Pasela Protite in 27 x 1-1/8" has Kevlar bead, is lighter, and you can carry a folding spare.

Schwalbe Marathon are still offered in 27" - I don't recommend them for ride quality - they have thick, hard, heavy rubber.
Panaracers are nimble.

27.5" tires are 650B (ISO 584) - you'd need rims and a major brake modification.
650B rims have made a big come back for gravel bikes in the last few years, and is the traditional French rando tire.
My buddy Lou's custom Chapman rando with 42-mm 650b doughnuts. (in addition to the frame, Brian Chapman built the crank, brakes, stem and racks). 




Note how far his canti brake is down the fork to reach these smaller diameter rims.

Best choice, buy a nice set of 700C rims, then you can use any new tires.
You only need to lower your brake pads by 4 mm to fit.





Tubes?  Don't ask.  I've made the move from latex tubes to urethane tubes - I'm a ride-quality junkie.


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## borgward (May 13, 2022)

Nice job.


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## bulldog1935 (May 13, 2022)

btw, here's what my buddy Steve did with his World Sport, beginning with a custom wheelset.




He has a Sram 2-speed auto hub - the two gears are 52" and 72".   Front dyno hub with full-time lights.  
The 52" gear will get you up most suburban hills around SA and Austin.  The 72" gear isn't fast, but is a pretty perfect cruising gear.  
Chain guard, crank, and brakes are Velo Orange.
I donated the Honjo fenders to the project, and he's riding 700C x 28-mm tires, which are equivalent to 1-1/8".


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## borgward (May 13, 2022)

What does "C" indicate? As in 700C? Thought it meant centimeters but that would be a gigantic size. Not familiar with that. I purchased a TERAVAL innertube. Made in Taiwan. Came in  recyclable cardboard box. 

700 28-35, ISO 28/35-622/630 printed on the box. Inflated in stages up to 70 psi. Not going to inflate these old worn out tires to 95 until I decide which ones to order.


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## Arnold Ziffel (May 14, 2022)

Just remember that when you see 700C that it is 622mm.

Because of all the different bicycle tires with seemingly baffling illogical size markings that sometimes were beyond confusing, that in the late seventies an International Standard of the wheel's Bead Seat Diameter (in millimeters) WOULD APPEAR ON EVERY BICYCLE TIRE MANUFACTURED,  FORWARD, FROM THAT POINT IN TIME,  IN ORDER FOR PEOPLE TO BE ABLE TO DETERMINE EXACTLY WHETHER A PARTICULAR TIRE WOULD FIT THE BICYCLE's WHEEL.

Those of you with the ancient coaster brake beach cruiser bikes in either balloon or middleweight configuration with 26 inch wheels, HAVE SEEN  559mm APPEAR ON THE SIDEWALL MARKINGS OF ALL TIRES MANUFACTURED SINCE THE VERY LATE SEVENTIES, or 1980.              
The early mountain bikes adopted this size in the Seventies and it (559) remained the mountain bike standard for the 1980's.
So 559mm never became obsolete, or rare,  while others did.

Heck it was already frustrating,  for  the average person trying to find new replacement bicycle tires for their family's bikes back in 1972.  There was no Bead Seat Diameter, international standard then!   You, maybe, probably had the only useful information in the SEARS catalog,  where they specifically stated DOES NOT FIT SCHWINN   --or--  This Tire Fits Schwinn's Only ,  in their descriptive chart of tires pictured in the catalog.    You could imagine the mom or dad who was trying to buy new tires for the hand me down bikes for  the sixth child.

I don't have a clue as to why the tire markings had original designated markings that were ridiculously illogical and nonsensical, other than  thinking that maybe they needed a classification name(NUMBER)  that had not already been in use by another different size.

ANYWAY the international standard that has been in place since the late seventies where you see the BEAD SEAT DIAMETER in millimeters,   preceeded by the expected  mounted tire tread width in millimeters.
   A  Few  Random Examples:
47 - 559   (26" mountain bike & ancient coaster brake/beach cruisers) 
37 -590     (NON SCHWINN 26 x 1 3/8,  also known as 650a , also known as EA3 )
37 - 597    (Schwinn 26 x 1 3/8,   also known as EA1,  also known as 650  ...note that this designation is 650 without letter suffix)
32-  630     (this is  27 x 1 1/4.....................once the dominant road bike wheel size, until 700C took over by 1985 or so)
35 -622      (this is 700C tire probably on a hybrid)
THE 700C (622mm) wheel replaced the 27" wheel (630mm) on upscale road bikes beginning in the late Seventies.
By 1986, there weren't any upscale road bikes that featured 27" (630mm) wheels.
The 700C wheel isn't any better or worse than the 27" wheel,  it was simply mostly a trend towards the 700C to distinguish the new from the old.



			https://www.westernbikeworks.com/tire-sizes-article
		







						26 Inch Bicycle Tires
					

There are several different bicycle tire sizes called



					www.sheldonbrown.com
				








						650B (584 mm) Conversions for Road Bikes
					

The 650B (584 mm ISO) tire size is enjoying a revival. It offers wider an more comfortable tires than the popular 700C (622 mm) size, and also makes it possible to install fneders on bicycles which have too little clearnace with the larger size.



					www.sheldonbrown.com
				








						Tire Sizing Systems
					

Several different systems of size markings for bicycle tires are in existence. The modern ISO system is not as familiar as it should be, this article explains it.



					www.sheldonbrown.com


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## bulldog1935 (May 14, 2022)

C is just the third letter possible.  At one time there were English and French 700 A and B, just like there are 650A tires still made for English 26" Lightweights.

What's left out above, 700C was the only tubular tire size going into the seventies.
If you look at old Raleigh catalogs, they spell out 27" tires in their specifications, and any listed as "alloy" rims are 700c.
700C clincher tires and rims were new in the 70s. 
Touring is the main reason 27-inch lasted as long as it did.  People could count on getting a needed 27" tire in just about any bike shop anywyere.

And of course you could buy quality 27" alloy rims into the 80s, such as Rigida 1320.
This was a photo of the bag, but you can see the blue (27") Rigida rim sticker and Pasela tire (700c Rigida rims have a red sticker)





wiki has this nice tire chart for 26"

Tire inflation - the only tires you should be inflating to 95 psi are 1" tires, which you don't want, but I did in the 70s/80s in Austin.
(I used to take Montopolis to cross the river, 7th St. across I-35, and could ride from Riverside apartment city into UT campus faster than the shuttle bus - back then, the city maintained the Waller Creek greenway from 6th St. to Waterloo Park and Jester - actually, Schultz's Beer Garden was the upper end)

Proper tire inflation gives you a better, safer, FASTER ride, and can make your tires last 10-times as long.
People over-inflate their tires because they mistake road chatter for ragged edge speed - the fastest tire stays in contact with the pavement, and maintains a round contact patch.
The weight on the tire determines the area of the contact patch, which is the same regardless of tire pressure.
The tire pressure determines the shape of the contact patch, an elongated oval at over-pressure, which wears the tire faster in a narrow band.


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