Chumba is a different type of bike company because it’s a small builder. When you walk into the offices at 8 a.m. on a Monday morning, you’re likely to find bins of raw metal
and tubing rather than cubicles and water-cooler banter. The
quality control personnel will be carefully checking over the tubing
to be passed off and then mitered for an exact puzzle-piece fit.
All of Chumba’s bikes are welded by the company’s highly skilled
welders, then carefully aligned using a 360-degree rotating alignment table. Yeah, these guys are perfectionists. As a bonus, this
process is entirely done in the United States. Chumba takes a lot
of pride in being able to display a made-in-the-USA sticker on its
products. These guys are craftsman in every sense of the word.
That’s why we decided to bring in Chumba’s newest creation, the
Ursa Major, for a full MBA-style test.
WHO IS IT MADE FOR?
The Chumba Ursa Major is built for riders looking for a bike that
can hold traction through the loosest of turns. The big tires don’t
mind getting a little hang time, and the American-made frame can
take quite a beating. This is a versatile fat bike—one that isn’t just
built for snow or sand riding. Riders seeking a lively bike will love
the geometry of the Ursa Major and trail riders might find them-
U.S. steel with lots of appeal
selves enjoying this bike as a great winter training tool. Chumba
tested the Ursa Major in varying conditions, such as snow races in
Utah, Idaho and Wyoming, and on the dirt trails of Colorado and
Texas. The Ursa major is built tough and ready to handle whatever
terrain you want to throw at it.
WHAT IS IT MADE FROM?
It doesn’t take long to notice the American flag on the seat tube
of this beastly bike. Chumba’s Ursa Major sports an American
hand-crafted steel frame and stainless steel sliding dropouts.
The Ursa Major has an oversized 44-millimeter head tube
and a threaded English-style bottom bracket. Chumba used a
197x12-millimeter rear thru-axle to gain a more responsive and
laterally stiff feel. The standover height was lowered for all sizes to
allow riders to touch the ground, even when standing in the snow.
WHICH COMPONENTS STAND OUT?
The sliding dropouts on the Ursa Major offer riders the ability to run either 4-inch- or 5-inch-wide tires while keeping the
chainstays short. The dropouts also allow the option to run this
bike as a single-speed. The cockpit displays a Race Face 35-mil-
limeter handlebar that is 760 millimeters wide and a 60-millime-
ter-long stem. The Rockshox Bluto fork with remote lock out was
an upgraded option over the steel fork that would normally come
with this bike. The Thomson Elite dropper post is also an upgrade-able item over the rigid aluminum Race Face seatpost.
HOW DOES IT PERFORM?
Setting tire pressure: Due to a fat bike’s large-air-volume
tires, a small difference in pressure goes a long way. When we
tested pressures around 15 psi, the balloon-sized tires bounced
us around like a 25-cent machine bouncy ball. We lowered the
pressure a little bit at a time and found the ticket for our local
trails was between 9 and 11 psi. These low pressures allowed for
gobs of traction and small-bump compliance without hindering
our climbing efficiency. One of our test riders said that a person