The bike business is a business like many others, ideas come
and ideas go, some good some bad and many are just there to let people know
that the company ain’t dead. Every once in a while an idea comes along and just
kind of hangs in the periphery, just waiting for their time to come. One such
idea is 650b wheels, not that the 650b wheel is a new idea, hell it’s not even
an old idea it has been around for decades, but to mountain bike designers and riders
it is relatively new. There are some people, and I myself am one, that contend
that if we had designed mountain bikes from the ground up in the beginning instead
of modifying road bikes and cruisers to go biking in the woods, we would
probably have opted for 650b wheels right from the start, however modifying
frames led us to the smaller 26 inch wheels that then became the mountain bike
standard for so many years.
few years ago we made the quantum leap to the 700c wheel, more commonly referred
to as the 29er, which has made a huge impact with off roaders. This has made it
difficult for the 650b though. Going so long with one choice, the 26, then
adding the 29er quite recently has meant some reluctance from mass manufactures
to add yet another wheel size and different bike geometry to already swollen
product lines. Luckily the fear of being left behind by the competition has won
out and we are seeing many choices from frame companies along with tire and rim
manufacturers for 650b. This is very good news. And here's why; Choices.
As mentioned before the industry
standard 26inch wheel MTB has been around since the start of mountain biking,
the 29er or 700c MTB wheel is a relative newcomer and the 650 b is the new kid
in town. The important thing to keep in mind here though is to not disregard
any of the old wheel sizes just because there is a new one. They all have their
place when looking for a new bike.
During this bike season we have seen
a lot of new customers, which is very nice, a lot of new MTB’ers have come
through the door as well and a good deal of them have opted for the 29er. Now
don't get me wrong a 29er is a fantastic machine but it is not for everybody.
Designing frames and frame geometry
for big wheels is tough, sure anyone can build a bike to accept big wheels but
getting the handling and feel dialed in is a very different matter and it is especially
difficult getting it right on mid to small frame sizes. We have seen many, many
riders lately that look like they have been swallowed whole by their bike and,
while this arrangement is fine for a gentle trail ride, on a more MTB specific
trail or good single-track it must be akin to riding a bull elephant with
Before I carry on let me clarify
what we actually mean when we talk about these different sizes. Below are the
measurements, in millimeters across the wheel, bead to bead. The bead of a rim
is about 3mm down from the top of the rim.
As you can see the 650 falls about
midway between the other two you will also note that the bead seat diameter of
the 29er is the same as a standard road 700c so why do we call it a 29er when
it is really only a modern 27inch road wheel. Well it is because some bright
spark decided to measure the diameter outside to outside with a fully inflated
mtb tire on, which gives you a measurement of roughly 29inches. Confused yet?
Anyway, back to the business at
hand. If you are a tallish or leggy
person the big wheel option is definitely a choice for you. The frame size will
be plenty to accommodate the extra clearance while still maintaining the ride characteristics
of a good mtb. All the rules of bottom bracket height and head and seat tube
angles still need to be obeyed and they can be with a mid to large frame size.
However, if you are, shall we say a little vertically challenged, this is where
problems arise. The rules of designing a bike to perform well for the rider
tend to get thrown out the window and it all becomes about designing a small
enough frame to at least reach the pedals on while the design is sacrificed to
fit a big set of wheels. This really does not work. The cut off for a bike
designed for the rider instead of the wheels generally falls somewhere around
the 5’6” mark. There are exceptions for those with exceedingly long legs in
relation to body height but generally speaking this is where sticking with the
26” wheels tends to be the better option.
Now though we have another option 650b.
This is where the slightly smaller size gives us, as frame designers,
much more scope to still design the bike for the ultimate ride and handling but
still giving the option of bigger wheels.
|A Soma "B-Side" Built and ready to roll.|
For those wanting to know more about
the options available in the 650 or 29er range stop in or fire me an email.
There are lots of choices. At the moment some of the best 650b frames tend to
be from companies like Soma who offer the B-side. I expect some of the major
names to start producing complete 650 bikes in the next year’s product line.