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