
This is the information for the m.c.r. 9:
The MCR 9 continues the tradition
of outstanding Niner geometry. The 29" wheel causes many
changes to the bike that needed to be addressed. It doesn't work
to just apply the standard 26" wheel cross country approved
geometry to the 29" wheel platform. The MCR 9 has a short
head tube to compensate for the taller front end, which will keep
handlebar positions from getting too high. In addition, the short
seat tube (16.5" for the medium) offers a better stand over
height while keeping the front triangle stiffer for those out
of the saddle efforts. This frame was designed for use with a
400mm seat post. S-Bend seat and chain stays allow for some vertical
compliance of the wheel as well as increasing the mud clearance,
lowering the Q factor, and creating more heel clearance. Short
chain stays (for a 29" wheel) keep the back end tucked in
and the wheelbase manageable while the longer effective top tube
lengths offer good stability and clearance from toe overlap.
If you took a glance at the geometry
chart, the 72 degree head tube angle might stand out as extremely
steep and alarm bells might be ringing. Remember, the larger wheels
alter the way the bike handles as well. By increasing the diameter
of the wheel, the "trail" is also increased. The trail
is determined by drawing a vertical line from the drop out of
the fork to the ground, and another line that follows the head
tube angle all the way to the ground. The distance between where
these two points meet the ground is called the trail (see
trail chart). You can see the difference in trail between
the 26" wheel (the smaller circle) and the 29" wheel
(the larger circle) in the chart. For a 71 degree head tube angle,
the 26" wheel has a trail of 76mm while the trail for the
29" wheel with the same head tube angle grows to 87mm (all
other tings being equal like the fork height, etc.). As the trail
becomes larger, the steering starts to have a flip-flop washed
out feeling. One way to compensate for this is to increase the
rake of the fork. Since we do not currently have enough power
to ask the fork manufactures to do this, we took care of it the
other way, to increase the head angle, thus decreasing the trail.
Once again, you can see on the trail
chart that the trail for the 29" wheel with a 72 degree
head tube angle is 80mm, much closer to the trail of the 26"
wheel with a 71 degree head tube angle. The 72 degree head tube
angle on Niner bikes gives the perfect balance of control and
liveliness to the front end. In addition, the Niner geometry works
brilliantly with either an 80mm or 100mm fork.
You'll notice that the SMALL Niner
has a slacker head tube angle and a steeper seat tube angle. This
was to allow for better toe clearance with the front wheel. With
the larger tires of the 29" wheel, toe overlap is an important
factor. We had to make sure that with the bottom bracket in the
forward most position, there was ample room for a normal size
foot to clear the front wheel. If you're 5'6" and wear a
size twelve shoe, you might have some problems here, but then
again, you should probably be in the circus.
One more important note on Geometry.
Our SMALL frame only has one water bottle mount. This is so that
the seat post can be lowered all the way without hitting the water
bottle mounts that would be on the seat tube. We felt it was more
important to be able to get the seat out of the way for those
hairy descents.