Most people love to offer advice but truly don't understand what the different tire sizing designations actually mean. The silly french system that cyclists love to bandy about actually represents a very convenient way to describe the rolling circumference of the tire mounted on the rim, and inflated. So theoretically any 700C wheel/tire should roll the exact same distance as ANY other 700C wheel and tire for one complete 360degree revolution. Now this certainly isn't true anymore, and that aspect of the 700A, 700B, 700C, and 700D naming system is essentially meaningless now. Tire and Tyre manufacturers "cheat" and undersize their tires to gain a marketing advantage on claimed weights for a given width be it 19, 21, 23, 32, 35, 38 or what have you. Only people like Jan Heine project normative value judgments onto the old French naming system. I would think most of the intelligent cycling community understands that a 700c designated wheel or tyre is merely just a 622 ISO size.

While the 29er wheel uses a 622 ISO rim, it most definitely is NOT a 700c equivalent. As the very notion of 700c implies a standard rolling circumference by convention. So while a 700c (really just a 622 ISO) rim/wheel and a 29er rim/wheel both use a 622 BSD (Bead Seat Diameter) they have very different rolling circumferences. 29er tires are massive and very wide and very tall, and have a much different rolling circumference from what the 700c rolling circumference standard was, read longer/more. To that end no one should really be using the term 700c anymore as its an ignorant term that doesn't represent what it originally represented, and is misunderstood. So what is true is that what people call a 700c (really a 622) uses the same BSD size rim as a 29er rim. Both a road 622/700c and a 29er tire are for a 622 ISO BSD.

A 630/27' tire or tyre actually has an 8mm larger BSD standard, giving it a slightly larger wheel diameter. Most cyclists, like Jan Heine, don't seem to understand that a misunderstood naming convention has NOTHING to do with how a tire/tyre affects the handling of a bike and we really should stop using terms like 700c, 700a, 700b, and 700d and 650b.

In the end these are the intelligent wheel/tire sizes to use:

559 - commonly called 26" or mountain bike/cruiser
584 - misunderstood as 650b which they are NOT in terms of rolling circumference
622 - misunderstod as 700c which they are NOT in terms of rolling circumference
630 - misunderstood as being "lower-quality" than "700c" by ignorant folks

There is nothing normative or "better" about a given wheel/tire size. What Jan Heine doesn't understand is the relationship of the wheel/tire size to the frame size/cyclist size. A 622/29er wheel on a mountain bike for a 6'5" cyclist on a 23" gives a totally different handling characteristic than for a 5'4" cyclist that needs a kooky geometry frame to accommodate it. While anyone over 5"10" can absolutely appreciate how the larger wheel diameter allows the bike to just roll over obstacles without a care that would require some technical skill a smaller 559/26" wheels. Smaller and diminutive cyclists actually seem to not actually like the 622/29er bikes because their tiny bikes require drastic and aggressive frame geometries that just really don't make sense, to allow the suspension front wheel to fit the tiny tiny frame.

Likewise, using the same 622/700c wheel on every frame size from 49cm through 63cm + bikes makes about as little sense. Jan Heine has tried to craft a false narrative that there is actually something superior about the 584 wheel size. However, once you start talking about the 584/650b wheel size in the 584 ISO language instead of using the language of "650b" for most intelligent cyclists the projection of normative value disappears. What Jan really needs to say is that he prefers a 584 wheel for his stature and frame size, and how that wheel feels to "him." There is NOTHING universal about wheel sizes. There are fifteen different touring/road size bicycle sizes using 1cm increments between 49cm and 63cm. Considering many many people, myself included ride bikes up to 70cm, there are actually twenty-two distinct sizes of bicycle frames, that are commonly used.

A given wheel/tire size just feels and handles completely different for bikes that sit at different places on the sizing spectrum. 622/700c wheels aren't really appropriate for very tiny bicycles. Terry who is known for their saddles these days, started out as a specialty bicycle accessories and builder for women's bikes. They did something relatively innovative at the time and used to spec a smaller front wheel on their tiny women's bikes because those frame sizes simply didn't accommodate the larger 622/700c wheel, in the exact same way that very small and women's mountain bikes don't accommodate a 622/29er wheel without messing up the handling/geometry of the bike. You can fit a 622/700c wheel into a very small women's road bike or a 622/29er road bike but in doing so you negatively affect the handling of the bike and booger up the geometry.

To that end it shouldn't be lost on anyone that a 584/650b wheel size that Jan Heine is trying to spread propaganda as being somehow "magical" as a touring wheel size, will feel completely differently on different size frames/bikes. What is lost on Jan, and I'm not sure its actually lost or if he's just being disingenuous, is that ANY given wheel size will feel differently to ANY different frame size on the bike size spectrum. A 584/650b wheel will handle and ride completely differently on a 49cm bike, a 56cm bike, a 63cm bike, and a 68cm bike. In fact its an absurdly small wheel for just about any bike over 57cm that will build a bike that doesn't handle as well. The very opposite of what Jan claims.

For bikes 60cm and above, it really has NEVER made sense that these bikes used the 622/700c wheel size. The 622 wheel is just really too small for these bikes. In fact most cyclist over 5'10" truly have no concept of how well smaller bikes handle for smaller cyclists. How stable the little people bikes actually are with a proportional size wheel set. Any bike over 60cm, and arguably over 58cm would really be using 630/27" wheel size or even larger. There is a 635 wheel size, but while you can get quality tires/tyres in 635 it is almost impossible to get quality rims in the 635 in the US. Most 635 bikes were for "rod brake" style cruisers, and only heavy steel rims in 635 are available.

In the 630/27" wheel size quality tires are prevalent. You can top quality touring tires/tyres from Continental, Schwalbe, Panaracer and narrower racing style tires are available from many manufacturers as well. Even Bontrager the Trek house brand has put out high quality road racing tires in the 630/27" size. The misnomer that 622/700c tire size indicates a "better" quality rim/tire is ignorant. What is true is that the 630/27" offerings have never been what they were during the US Bike Boom days when the 630 tire size was prevalent, and fewer rim manufacturers are making 630 rims. Velocity, Sun others still make plenty of quality 630 rims in a variety of drills and widths. However, it isn't true that the 622/700c is a European size compared to 630/27" being a US size for low end bikes. European rim manufacturers made plenty of 630 size rims for their market as well. While many of these were never imported to the US, rim makers like Exal (Belgium), Weinmann (Swiss later Belgium), Rigida (France), Alesa (Belgium), MAVIC (France) all made plenty of 630 rims for the non-US market.

So much of wheel/rim sizing is completely misunderstood. What is true is that most bikes on the road today don't have the appropriate sized wheel/rim. Manufacturers and distributors want a "one-size-fits-all" approach to wheels/rims/tires which makes about as much sense for bikes as it would for cars.

I would strongly encourage anyone thinking of switching from a 630/27" wheel size to 622/700c to think twice. The incrementally smaller 622 wheel size translates bumps, cracks, and road imperfections much more so than does the 630 size, which is remarkable considering the marginal 4mm radial variance. However, the larger 630 size is just so much more smooth even for a given tire width with the identical model tire compared to its 622 cousin. Bikes 58cm and larger handle much better with the 630 wheel size, and bikes that are 60cm and larger just handle poorly with the smaller 622 wheel size. With 630 wheels a given bike is demonstrably more stable (a significant problem for larger frames that smaller cyclists have no frame of reference for), is faster on the flats and rollers and maintains momentum better (bigger "flywheel" analogy), and the bigger wheel size reduces speed wobble as well.

I've always felt that bicycles should have proportional sized wheels. Soemthing Jan Heine, seemingly, doesn't comprehend that different wheel sizes "Feel" different on different sized bicycles for different sized people.

If this was my Grandad's bike I'd build it up using a quality hubset like classic Mavic hubs with Mavic Module E rims in 630/27", the drill and spoke choice would be a function of rider weight.