650B Tubulars?

650B wheels have been in the news lately. 650B appears to be the “next big thing” for mountain bikes. The popular 700C mountain bikes (“29er”) don’t offer the nimble handling you need in technical terrain – the same result we found for wide 700C tires on the road. For 2013, several big makers are introducing 650B mountain bikes.

What better way to promote a new idea than by winning races? Last weekend, Nino Schurter made history by being the first to win a World Cup race on 650B wheels.

In an earlier version of this post, I suspected that Schurter was riding on 650C wheels, which mountain biker racers have been using for a long time. Several companies now make mountain bike-specific tubular rims, but it appears that what is called “26 inch” really are 650C rims. Now 650C is 571 mm, and 650B is 584 mm, which is only a small difference. So even if the new rims are 650B, one wonders what the big deal is all about: Professional mountain bikers have been riding on 650 (C or B) tires all along.

Perhaps more important is what this “650B boom” means for those of us who ride 650B on the road? We can expect more 650B components, but how useful these will be is another issue. Many of the rims probably will be disc-specific, which means that the rim sidewalls will not be thick enough to accommodate brake wear. (With rim brakes, they will be below the safe limit after your first ride in the rain.)

As for tires, if the current selection of 26″ tires is any indication, then we shouldn’t expect too much. Most slick 26″ tires available today are heavy and slow. It makes more sense the other way around: Mountain bikers would do well to choose 650B wheels. On the road, they could use the many wonderful 650B tires that are already available. On the trail, they soon will have a great selection of knobbies.

For us, who ride 650B on the road, this leaves the intriguing concept of 650B tubulars. Wouldn’t that be neat? We could have Dugast or FMB make a small run of 40 mm-wide road tubulars. Like so many things, this has been done before: tubular 650B “Demi-Ballon” tires were popular in the 1930s. Back then, riders found that tubular tires provided little additional advantage when wide clinchers had so much air volume already. The wide clinchers already were very comfortable and did not suffer from pinch flats, both advantages usually associated with tubular tires. With wide tubular tires, the hassle of having to carry several bulky spares was even greater than with narrow tubulars.

In the end, we are lucky that the 650B wheel size is well-supported already. And perhaps the next big thing after 650B mountain bikes will be 650B for the road. Now that would be something!

Photo credit: James Huang, Future Publishing

About Jan Heine, Editor, Bicycle Quarterly

I love cycling and bicycles, especially those that take us off the beaten path. I edit Bicycle Quarterly magazine, and occasionally write for other publications. One of our companies, Bicycle Quarterly Press publishes cycling books, while Compass Bicycles Ltd. makes and distributes high-quality bicycle components for real-world riders.
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21 Responses to 650B Tubulars?

  1. From what I’ve read, DT Swiss had been working on 584mm rims (and a matching fork) for a while and so I guess these were the result of that.

    As an aside: maybe the proliferation of wheel sizes will finally lead people to use ISO measurements instead of the horrible inch-based or the French system…

    • I agree on the ERTRO measurements in millimeters – Bicycle Quarterly has been using it for years – but I don’t have much hope. At least the stupid attempts to call 650B “28.5 inch” (half-way between 26″ and 29″) has not caught on.

  2. Paleo Velo says:

    For the cyclotourist and randonneur crowd, I think some grand bois tires that had a tight enough bead to be set up tubeless would prove far more interesting. You’d get the benefits of a thin, supple tire, yet it would remain almost flatproof due to the sealant.

  3. Chris Lowe says:

    Doubt it’s 650c. AFAIK DT doesn’t make a 650c carbon rim. Actually, I don’t think they even make a 650c rim in aluminum. On top of that every 650c tubular rim I’ve seen would be too narrow to run a MTB tubular. Most were made for time trial use and wouldn’t provide a solid enough bed to keep a MTB tire from rolling in a hard corner. My guess is that they are 650b carbon rims.

    • I suspect it’s not a DT rim at all. There are plenty of carbon 650C tubular rims around. 650C rims have been used on mountain bikes for many years.

      Note that 650C (671 mm) exactly splits the difference between 26″ (559 mm) and 650B (584 mm). They’ve been pretending that the 650C wheels were 12 mm smaller in the past, why not pretend now that they are 13 mm larger?

      Few people are “shocked, shocked” that racers don’t always ride on the equipment they are said to ride. (Just consider the “Eddy Merckx” in our book The Competition Bicycle, which was built by De Rosa.)

      Of course, my suspicion is just conjecture, but until somebody shows me the rim or I see some trusted source measure it themselves, we really don’t know. Maybe I should offer a prize for the intrepid Internet researcher who figures out what rim they used?

  4. RJ says:

    Jan,
    You say, “Currently, no one makes tubular rims in 559 mm (26″) or 584 mm (650B).”
    I can only point out that no one you currently are aware of does so. Sorry to be coy but for me to elaborate would be discussing knowledge shared in confidence.
    But the coming year will be an interesting one indeed…

  5. rodneyAB says:

    Tubulars don’t excite me much, though the idea of a supple casing such as the Pari-Moto, or perhaps the Hetre, does, but more exciting than either, is the upcoming introduction by Pacenti of his PL 25 rim

  6. Christopher Grande says:

    I’m not sure what to make of this step for 650b. On the one hand, it gets the name out there and people thinking, but on the other, the logic behind MTB and road applications for the wheel sizes are coming from different places. For MTBs, there is a bit more wiggle room for experimentation in some regards since weight, although still important, isn’t nearly as much in the spotlight as it is for road. Things like Tubeless systems and longer travel suspension are evidence of this.

    650b also has the advantage for MTBs in that it ‘rolls over’ stuff better than 26″, which is a much easier point to argue for in our normalized ideas about bikes than what you have to argue for in 650b applications for the road. First you have to argue for wider tires being just as fast as skinner tires, which you’ll lose probably about 90% of the industry there (conservative guess.) And not just 28mm over 23mm, but 38-42s over 23-28s. Then you have to argue about gyroscopic forces in the wheel over sizing the wheel to the rider, yada yada yada. All good points, but very much against the grain.

    I’d still say that 650b road still has a ways to go, but watching the development of MTBs is still pretty interesting. We’re still too competition obsessed, so maybe if there was some new wiz kid to win a major road race on 650b, the chances would be better. Or cyclocross? I don’t know.

  7. Bubba says:

    “Currently, no one makes tubular rims in 559 mm (26″)”

    Mavic is releasing lots of tubular wheelsets in 559. BikeRadar had a story on it a couple days ago. GEAX has made 559 tubular rims. I don’t know if they still make them, but you can still buy them. For example, here:

    http://www.cambriabike.com/shopexd.asp?item=100037229

    You can also find GEAX and other makes of 559 tubular tires without much difficulty.

    • alex wetmore says:

      I don’t see anything there saying that this is 559mm BSD (and of course BSD doesn’t mean anything really with tubulars).

      The ERD is 546mm, but it looks like a pretty tall rim. The Sun CR18 is about as short of a rim as one finds in 559mm BSD and it has an ERD of 548mm. I think that Geax rim is really 571mm equivalent, and it sounds like other “26 inch” mountain bike tubulars are as well.

  8. Russell says:

    Please share with us an example of these 650C MTB wheels and tires…

  9. James says:

    I think it is an exaggeration to say that “650C rims have been used on mountain bikes for many years”. 650C has never been a standard size and I challenge anyone to find just one readily available mountain bike tire in that size. I wish I had a QBP catalog nearby, but I’d still place a bet on it.

    Also, as an avid mountain biker, it is also an exaggeration to say that 29ers are not nimble in technical terrain. That simply is not true and if any of you find yourselves in the Bay Area of California, I will be glad to prove it to you. Obviously, geometry and a host of other factors determine nimbleness – my Niner SIR9 steered much quicker than my Santa Cruz Bullitt (29er XC geometry vs 26 inch freeride).

    • You are right that for normal mountain bikes with clincher tires, 571 mm (650C) is not a size that has been used. The standard size is 559 mm (26 inch). However, for professional mtb racing on tubular tires, 571 mm (650C) appears to be the standard size.

      The quote about the lack of nimbleness of 622 mm (29ers) was from the original source. I think it is attributed to Thomas Frischknecht. This was the reason they gave for introducing the 584 mm (650B) wheel size for (clincher) mountain bikes.

      • faulpelz says:

        Sorry Jan,
        there are 559 tubulars for mtb. Wolber made them many years ago, and some brands (f.e. Geax, FRM) are making them again. And if you compare a 571 tubular rim (the triathletes used them) and the rims for mtbs, you will note a small difference. And the Dugast and Geax tubulars will give you nothing but hell, if you try to mount them on the bigger 571 rim. (I tried it.)
        Regards, thomas

      • I asked both Dugast and FMB about this. François Marie, the owner of FMB, told me: “The sizes for mountain bike tubulars are very confusing. I assemble our mtb tubulars with the same casing lengths as our 650C tubulars. Tubulars can stretch quite a bit, so the actual dimension is less critical.”

        What we really need is somebody who has a tubular mountain bike rim and can place it on top of a 559 mm clincher rim to compare the dimensions. Anybody?

  10. Paul Ahart says:

    Just as an aside note: I’m a Specialized dealer, and received an email from the company this past week or so stating they WILL NOT be offering anything in 650b in the coming year. Two years from now? Who knows? Their comment was that there were already enough wheel/tire sizes on the market, and that 650b was not different enough from 26″ and 29″ to bother offering.
    I personally have been joking with my rep about the company offering a road bike (for touring/randonneuring in 650b. He just stared at me blankly about this.
    As an avid proponent of 650b for touring/randonneuring, I predict the market for this size will increase enough that major brands will decide to get involved. More people tour than race, but you’d never know it when viewing the ads.

  11. RJ says:

    As Specialized is a huge company it doesn’t surprise me that they are slow to respond to market developments. I naturally expect the smaller, more agile (and arguably more hungry), manufacturers to have their 650B products available sooner.
    As far as the reps comments about there already being enough differentiation in wheel sizes the market will ultimately be the judge of that.

  12. HillDancer says:

    To Paleo Velo’s comment, tubeless capable 650b rims exist already on which I suspect Grand Bois Hetre tires will seal well enough. I’m using Hetre tires on a tubeless ready disc brake rim and the bead is very secure, at least at pressures above 30psi.

    I don’t doubt a tubular 650b rim in carbon for disc use will make it to the market this year.

  13. Doug says:

    I ride a 650b mountain bike (Soma B-Side), fully rigid, single speed. My mountain biking history isn’t deep enough to offer real insight into the comparative merits relative to 26″ and 29″ wheels, but I’ll say that it’s super fun and I don’t have a problem rolling over most of the roots and rocks we have here in the Northeast.

    As for 650b tubeless for the road, I think I remember seeing someone on the tarckbike.com forums that had success with a tubeless Hetre setup on a Velocity Dyad rim. Anything is possible!

  14. Stephen says:

    Back in the late 1980s or early 1990s Mavic offered tubular MTB rims and Wolber (or someone else European?) offered tyres to suit. These were not big sellers, but I am certain that they had the same brake radius as 559mm wired-on rims – that was the sole MTB size back then. I saw these at the then Mavic importer’s warehouse, but very, very few ever sold; I never saw any on bikes in the field.

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