dddd

I found it interesting that, around 1990, Some 700c MTB's were sold and used a 700x45-sized tire on a narrow rim.

I later raced on such a bike that I re-purposed from the world of replica antiques, long story but the tires were available for as long as I still needed them.

Much later, the 700c mtb came back, but as a "29er" with wider tires.

Yet Panaracer (who made my old "Smoke45" tires), in recent years introduced a FireXC45 tire, basically an updated tread on the old Smoke45's.

WTB tried to get everyone thinking in metric widths, both casing width and tread width, but eventually added the old inch sizes back onto the sidewall info.

LesterOfPuppets

One of the funnest parts of working at a bike shop is trying to find out which 26" tire a customer wants. 559, 590 or 597 covered most that dropped in when I was doing so.

John Hood

Agree entirely, but it's actually even worse than you describe. Standard automotive tire sizes start with the tread width in millimeters, then the next number reflects the percentage of the tread width that would account for the sidewall, then there's finally the rim size in inches. So, 205/70/R15 would describe a tire with a 205 mm tread width, 143 mm sidewall and 15" rim and you'd practically need a slide rule to figure out the diameter of the stupid thing.

Now the imperial system for off road tires on the other hand is beautifully simple. 33x12.5x15 would describe a tire 33" in diameter, 12.5" wide for a 15" rim. That's the standard we ought to adopt. I don't even care if it's in inches or millimeters, what matters is that it's simple and accurate. Anyone can understand outer diameter, width and rim size.

cadillacmike68

I finally switched my wife's Shogun 400 from 27" to 700C. That way I can swap in one of my tubs if she gets a flat (or 2 flats, since I built 2 sets of 700C wheels for her). I gave the 27s to an LBS, they had very little use and had never been crashed.

Found 2 pairs of nice, unused, polished Araya 700C red label rims. one pair has eyelets and the other does not.

As for my bike, I built 5 pairs of Mavic Championnat Du Monde Professionel (2), Super Champion Record du Monde (2) and MilRemo Super Club (1) wheels all on Campy Record Low flange hubs. All with New (30+ yrs old, but new) Berg Union chrome double butted spokes with the 4 leaf clover on the end, just like the bike originally came with. All 36H tubs. I should have enough wheels for the next 20 years.

Wogster

I think the real ideal is a tire size based on the rim size, with a factor for tire size, for example a tire with 622-17 would fit a 622mm diameter x 17mm wide rim. Then add the outside diameter so, a tire that is 700mm outside diameter, would be 622-25-700 this could be applied to All tires, so a car tire that fits a 17" wheel that is 6" wide that has an outer diameter of 23" would be, 432-15-584 Then add a letter code to define the tire type. A manufacturer would simply need to specify the rim size and the maximum tire that will fit.

MKahrl

What's remarkable is that so many 27" tires are still being made for a rim size that was phased out thirty years ago. Samsung no longer makes the battery for my two year old cell phone.

27" was the most popular wheel size in the U.S. when FOUR MILLION bicycles were sold here in just four years. And a lot of these bikes are still on the road today. I was visiting NYC this weekend and saw dozens of thirty and forty year old bikes being used. It says a lot about the fundamental soundness of the "10-Speed" design.

John Hood

There are probably dozens of ways that it could be standardized that would make good sense so long as it were simple, uniform and informative. What's amazing is that hardly any of the common tire sizing standards are any of those things. You'd think that at some point someone would get it right and then everyone else would jump on the band wagon.

753proguy

The tires are marked with their ETRTO dimensions, but I get your point.

(A-nother Mechanical Design and Release Engineer).

753proguy

Where is 650c common, these days? Not in my universe...

eschlwc

what about the history of width sizes for 27" tires for mid/upper level bikes?

was 1" always the most narrow available? did marketers go this narrow on their new 'performance' road bikes, or was the substantially fatter 1 1/4" more standard, even for 'racing' type applications?

.

in a thrift store for $15 each, a friend of mine found me a nos mavic ma2 27" wheelset. they're so awesome looking. i put 1" paselas on them, and they look great. but, honestly, 23mm tires would look even better to me. just wondering if even more narrow tires were ever available for 27".

753proguy

What we don't see, though, is high-performance 27-inch tires. No new high-end tires are being molded in 27-inch, as far as I know. I wish there were just one super-high-performance 27-inch tire. 27 x 1 & 1/4" would probably be the size to do, but no one can be convinced to make the investment....

What do folks consider to be the 'highest-performance' 27-inch tire currently available? The Paselas are decent, the Conti Gatorskins are tough, but neither is really a high-performance tire, these days.

753proguy

Avocet paid for some 1-inch, and even 7/8-inch slicks to be made, way back when. Pretty narrow. I'd stay with 1-inch or wider, personally. We used to set up a lot of our 'fast' bikes with 1 & 1/8" tires, back then.

Edit: Measure the inflated width of your Paselas. They are notorious for being narrower than stated, in many cases. You may already be running 23s!

jimmuller 

I had one MA2 for many years, a replacement for some other rim which pretzeled itself. Bent it this spring. Nice rim too.

There could have been 27" tires 1" or narrower long ago and I just never saw any whenever I was looking to buy tires. As I remember it Specialized came out with 1 1/8" tires rated for 90psi some time around the late 70's or maybe as late as 1980. They seemed a radical innovation at the time compared to the common Michelin or Hutchinson typically rated at 70psi. I bought some as soon as I heard about them, really like them. Maybe a year later they introduced a 1" tire rated at 95psi and then 100psi. I tried the 1" variety too, like them.

I don't recall the exact dates for any of these though. And as I say, narrow high-pressure may have been available before them, but just not commonly available. More often than not high-performance bikes had tubulars anyway.

prathmann

As I recall, Michelin introduced the first really narrow, high pressure, clincher tire, the Michelin Elan, in 1975 and Mavic came out with the corresponding Module-E rim at the same time. They were available in both 27" and 700c sizes. There were some reliability issues and there were quickly competitors, incl. Specialized for tires and Rigida for rims.

Pompiere

I keep seeing this statement repeated, but both pairs of Paselas that I have measure exactly what the sidewall says they should. The 27x1 is 1 inch wide and the 27x1 1/8 is 1 1/8 inches. I have tires from other companies that are a full size narrower than advertised, as in a 700x25 that is really 23mm and a 27x1 1/4 that is really 1 1/8".

Wogster

I think 1" was about it, there may have been some custom ones, there were two issues, one is that hooked rims were not common in that size, and without it, you were pretty much limited to 80PSI and lower. The other is that tubular tires were common for high performance applications, so the narrower, higher pressure tires were often tubulars, which were not made in 27" size. Modern hooked rim clinchers have pretty much eliminated the need for tubular, which is why they are no longer as common as they used to be.

jimmuller 

Mine too. All five bikes within a mm or what they claim to be, certainly not a whole size too small.

In fact, I don't recall ever seeing any reference to hooked rims at all back then. Of course I may have forgotten. I ran them at the rated psi on the straight-sided Fiamme Yellow Label clincher rims, not a superb rim but light. Never had a blow-out until recently when I tried running a 25mm Pasela on them at its rated 115psi. That prompted me to rebuild the wheels with different rims.

753proguy

As they say, your mileage may vary. I think Paselas are truer to size now than they were years ago, and as always, rim width matters, but I have a bike with 700 x 35 Paselas, (which are also marked 37-622, by the way!) on quite wide (23 mm) rims, and they measure about 30.8 at max. pressure.

Wogster

There may have been a few hooked rim 27" wheels built at the very end of 27", before they stopped being used on new bicycles all together. What is interesting is that some bicycle frames, even as early as the mid 1970's were designed to go either way. Maybe because the bicycles needed to be able to deal with tubulars which were never built in 27". Maybe because the frames were designed for multiple markets where the frame could be assembled in the US or Canada for 27" or in Europe or Asia for 700C was much more popular.

Wogster

The issue is that with much of the marketing being US based they keep inventing new inch sizes rather then simply using the existing size designations, which are metric based. Things like the new 27.5 inch designation for 650B (ETRTO 584) and 29" for (ETRTO 622). The question for Joe Blough is whether he has a $49 bike or a $49,000 bike is no matter what the designation, what is the smallest and what is the largest tire that will fit. This is where the sizing systems, no matter which one is used, fall apart. Including ETRTO.

Perhaps the best designation would be this:

Bead Seat Diameter, plus 2 letters designating a width range of tires, for example A = 17mm, B = 19mm, C=21mm, D=23mm, E=25mm, F=28mm, G=30mm, H=32mm, J=35mm, K=38mm, L=40mm, M=45mm, N=50mm, P=55mm, Q=60mm, S=65mm, T=70mm, U=75mm, V=80mm, W=85mm, X=90mm, Y=95mm, Z=100mm+

So a rim might be marked as 622CH meaning that it's designed for a tire that is 21-32mm wide. A bicycle might be similarly marked as 622CK where the frame and components are designed for tires as narrow as 21mm, or as wide as 38mm. By moving to letter sizes, you eliminate the inch/metric issue.

Sixty Fiver

Avocet TT30 clinchers were made in a 27 by 7/8 and were insanely light and fast rolling folding tyres that are also a little delicate... these are considered to be the best high performance tyre ever made for 27 inch wheels but they are no longer made and the last ones I ever saw were being sold at Harris Cyclery about 6 years ago.

They feel like tubulars on the road... the wheelset they lived on is now on my Garlatti and these are Araya 1W red label hoops of very good quality rolling some Conti 1000's.



I prefer using the ISO designations although I am fluent in French and fractional sizing.

In our collection of bikes I have 349, 406, 451, 520, 559, 571, 590, 597, 622, and 630 wheels and tyres... used to have a few 635 models too.

Back to the 630...

Schwinn and Raleigh both adopted this wheel sizes for a great number of their bicycles save for the top of the line racing models which often came fitted with tubulars and the Japanese also used this tyre size widely and as such, produced a good number of decent rims.

As such there are millions upon millions of bicycles that are still rolling around on these wheels and tyre manufacturers still produce tyres... this last little bike boom brought a lot of these bicycles out of deep storage and our sales of 27 inch tyres has been brisk for several years.

crank_addict

Agree. I still have some 27 x 1 made by IRC. Fast roller, not too bad in rolling resistance. Haven't actually measured width as mounted but looks less than one inch - probably under 7/8".

crank_addict

Like the 27" someday our 700c will be rare

oh no! - the 36 incher:
XXXVI DG concept bike | thisandthat.com.cy

dddd

There were many brands offering hook-bead 27" rims, in both racing and touring widths, and both single- and double-walled styles.

These seemed to have been sold from about '75 to '89 as O.E.M. spec on road bikes.

The 27" Pasela tires in each of the three widths are among the widest 27" tires, almost fully up to their listed widths.
Only the Michelin gumwall (1-1/4" only) seems to measure as wide at 32mm (1.25") on a decently-wide rim.

Older 1" tires were the same width as 25c tires from the same period, up through the 1980's at least.

These 1" and 25c-labeled tires also carried molded-in designations of 20-630 and 20-622, respectively, during the later years of the 27" era.
The molded-in dimension was the more accurate.
I also bought "TurboSport" tires labeled as 27x1-1/4" which carried the (accurate) molded-in size designation of 26-622, made by Cheng/CST and sold by Specialized.

Current standard 1-1/4" gumwalls from Kenda, Cheng, etc. seem to measure 28mm wide on 22-23mm-wide rims after overnight inflation to rated psi.
But on the Varsity, with 28mm-wide steel rims, they measure 31mm after overnight inflation.

Performance sold 27x1" tires up until a couple of years ago that measured 21.5mm on 22mm-wide rims.

The IRC Triathlon was widely distributed in 27x1" width until recently, and was a very sporty tire with a tread thick enough to be called durable.

Current 27x1" Pasela tires measure about 26mm wide on a 22mm-wide rim, fully as wide as tires that some companies label 1-1/8"
Paselas in 1-1/8" size are easily as wide as most 1-1/4" tires from other brands, and I've had clearance issues after this full width took me by surprise.

Road Fan

On triathlete bikes, that is the 650c's.