icedmocha 

https://www.schwalbetires.com/Schwal...ed-11601054.01
Size: ETRTO 35-622 (28x1.35 Inch)

Is that 28c or something bigger? I am looking at a bicycle that has a maximum size of 28c (time alpe d'huez), and these are my current tires. I am missing something completely obvious and not sure what it is. Thank you for any help

stevel610 

The 28x1.35 is a European measurement. The 35x622 ERTO means the tire is 700x35c.

Camilo

It is not a 28mm wide tire (which is what you mean by 28C?). The 622 is a diameter measurement for the wheel itself, the ERTO nomenclature for a 700C wheel. The 35 denotes a 35mm tire width. So 35-622 = 700CX35, aka 700X35C. In either case the "C" refers to the classification of the wheel size, not the tire width.


1.35, in the 28X1.35, is the width of the tire in inches, equal to 35mm (which of course would actually be 1.38"... so I guess 1.4" would actually be closer since they want to round to the nearest .05")

The 28 denotes an approximate 28" diameter of the wheel and the mounted tire (in inches). It is the same 700C/622 wheel with a medium sized tire (in this case 1.35"/35mm), as opposed to the same 622/700C wheel mounted with a fatter (2-3") MTB tire - that would be called a 29-er! (PHEW!).

Dumb and confusing all around, except the 35X622 which is very precise and non-confusing labeling if you know what the ERTO system is. It should be the only system used, imho.

Why should I know this stuff? It's just dumb that I have had any need to or that you do. And I apologize for any unnecessary pedantry.

Thanks to the late great Sheldon Brown: Tire Sizing Systems (sheldonbrown.com)

rsbob 

Went to Sheldon Brown’s site. OMG, tire sizing is such a needless cluster. A standardized sizing nomenclature shouldn’t be that hard.

LesterOfPuppets

It's totally standardized, if you can find the xx-xxx, or sometimes xxx-xxx if you're into fatbikes. But yeah the inches and the As, Bs, Cs are all over the place

LesterOfPuppets

There are also tubular tires called 28", but they're usually skinnier 23mm or so.


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LesterOfPuppets

Bikes found in Target, etc began putting 28" callouts on their hybrid bikes a few years ago here in the USA also.

KerryIrons

25.4 mm per inch. 25.4 X 1.35 = 34.3 mm. Simple as that. Of course the actual mounted size of the tire will vary based on rim width and how accurate the manufacturer is, but there is no way this tire will fit in a frame that says 28 mm max. Note that is 28 mm, not 28c. The "c" refers to the rim size, as the Sheldon Brown web page describes.

JohnDThompson 

That's what the ETRTO/ISO size designations do. I tell people to ignore the archaic inch-size and A-B-C designations and only pay attention to the ETRTO/ISO designations, which look like "35-622" where the first number is the nominal width of the tire and the second number is the bead seat diameter. The bead seat diameter is the most important part, as it determines whether the tire will actually mount on your rim. Rims can accommodate a range of tire widths (frame clearance is often a deciding factor when choosing tire width), but the bead seat diameter must match, or the tire won't mount.

rsbob 

Now only if rims had a stamp or label stating the same. I know to match the size with the tire that came off, but if you just have an unknown rim, then measurements, etc.

JohnDThompson 

Some do, but by no means all. I think tires are required to be marked with ETRTO size designations, but not rims.

ThermionicScott 

That's like saying we should all speak Esperanto. I find it kinda fun to be able to "speak" multiple systems.

Camilo

Obviously I do too since I went into all that detail. 😎

Camilo

I can't tell from the labeling, do they fit 700c tubular wheels? I guess I'd assume so, but you know what they say about assume.

wolfchild

Wow some people just muddy up the waters and create confusion...The simple answer to OPs question is the tires in question are 700 x 35mm. That's all that matters here.

spclark 

Hehehe... for awhile I tried Beta vs. VHS but that got decided by others fairly quickly.

35mm vs. 120/220 for years before that.

I've somehow managed to limit it to Imperial vs. Metric the last 1/3 of my close-to-75 years.

If it's really, really important to you you'll work to wrap your head around a nomenclature as it applies to your non-trivial pursuits.

base2 

Prompted from above: I didn't find what I was looking for regarding the actual difference between beaded and tubular bead seat diameters. (They are different, btw. (Tubular rims are 632mm. No, Really.)) But I did find this: https://en.m.wikipedia.org/wiki/ISO_5775

Could be interesting from a general discussion standpoint.

LesterOfPuppets

How are they measuring BSD on tubulars? Seems like middle of the tire bed would make the most sense to me. Slightly surprised it would be that big there though.

LesterOfPuppets

Yeah those are standard road tubulars.

base2 

Rim edge to rim edge since there is no lip or anything to hook in to and it glued to the outermost surface. The brake tracks are in the same place though. So, typical "700" naming convention seems to be the order of the day when researching. It's probably a smart omission among manufacturers. The various systems are confusing enough.

spclark 

Thanks for that.

Helps having another approach laid out when next I try again to wrap my head around tire / rim sizing specs.

LesterOfPuppets

632 at the edge sounds reasonable, maybe 636 for some CX rims...

ThermionicScott 

I have an affinity for Beta since it was the first system we had when I was growing up. My folks were late adopters of VCRs and a family friend gave us (or maybe sold at a really good price) a whole bunch of Beta tapes when he switched to VHS, some official releases and others taped off the air. My siblings and I put a lot of wear on those tapes! When we finally got a VHS player, I did appreciate the extra runtime of those tapes.

JohnDThompson 

That's because they don't have, or need, a bead seat.