How high should I put my saddle? Will this Lefty work with my 27.5-inch
wheel? Does anyone have a shifter
schematic? Where do these extra
We love answering these ques-
tions and many more every month.
Got a question of your own? All
you need to do is visit our website
( www.mbaction.com) and click the
“Ask MBA” tab. Scroll to the
bottom of the page and hit the
link to ask your question.
this height, your leg is totally extended
with your knee locked out. When you
move your foot to the proper riding
position (the ball of your foot over the
pedal’s axle), your knee will have a
slight bend to it. This is a good saddle
height. You never want to lock out
your knee when pedaling (saddle too
high), and you don’t want an excessive
bend to the knee at the bottom of the
crankarm rotation or you are not going
to get full power out of your legs.
One more word of caution: your
legs may not be the same length (most
people have this condition). If one leg
is a bit shorter, use that foot to set
your saddle height. If not, you might
end up locking one of your knees when
Q: Cannondale says that a Lefty fork
can be used with 26- or 29-inch-
diameter wheels with appropriate
travel-limiting spacers. Can I use a
27.5-inch front wheel? What will it do
to my head angle?
—Jeff, who is checking out all his
A: Officially, Cannondale cannot say
that the current 29-inch Lefty forks are
designed for 27.5-inch wheels; however, we don’t think it will be long before
Cannondale offers a 27.5-inch-specific
Lefty. Remember that when many of
these forks were being developed, 27.5-
inch wheels were still a niche area of
the mountain bike market and were
most likely not tested with the forks.
That said, you should be able to
adapt a 27.5-inch wheel on there,
though we would definitely stick with
the 29er travel setting just to be sure
there are no clearance issues when the
fork is bottomed out.
As far as the steering, it will slacken
it up a bit, but we are talking a very
modest change in geometry. It will be
nothing like slapping a 29er wheel on
there. On paper, replacing the 26-inch
wheel with the 27.5-inch wheel will
give the same effect of making the head
tube angle about half a degree slacker.
You would have to be one sensitive
rider to feel that difference.
ON OUR SIDE
Q: I read that tubeless-ready tires
have ultra-stiff sidewalls that self-seal.
What exactly does that mean? Also, if I
let all the air out of a tubeless tire, how
easily can I air it up again?
—Jorge, who wants to ditch the tubes
A: You sure didn’t read that in
Mountain Bike Action. That ultra-stiff
and self-sealing statement is just plain
wrong. The sidewalls of a tubeless-
ready tire are thinner than a tubeless
tire and about the same as a tube tire—
unless it is some crazy-lightweight,
cross-country racing tire. Tire compa-
nies use different treatments for the
sidewalls of tubeless-ready tires so they
are less likely to bleed or seep air over
time, but this treatment does not have
a self-sealing feature (the tire sealant
takes care of that job).
The hardest time you will have seating a tubeless tire to a rim is the first
time you mount it. After that, it should
be easy to get the tire to bead to the rim
and inflate. Just remember to always
carry a CO2 and a spare tube on rides. A
CO2 will do a much better job re-seating
a tubeless tire on the trail, and in case
that doesn’t work, a tube and a regular
tire pump will always have your back.
DON’T TOUCH THAT
Q: I have a routine maintenance
schedule that I perform on my bike.
The two areas that I’ve never touched
are the brake-lever assembly and shift
levers. Do these parts need to be disassembled, cleaned and lubed?
—Jim, who likes to tinker
A: First, congratulations on the routine maintenance. That is a great habit
to develop. Now, to your question. You
do not want to service either of those
components. They are both sealed
systems that do a commendable job of
keeping contaminants out while keeping their internals working smoothly.
Disassembling a shifter is like
Q: What is the best method for setting saddle height? Is there a formula?
—Dave, who wants full extension
A: There is no one saddle-height
formula; there are hundreds of them. If
you ever want to start a heated debate,
just drop that question on a group of
roadies who treat dialing in the perfect
saddle height like finding the holy grail.
Mountain bikers, who move around on
the bike a lot more than roadies, don’t
have to be as finicky as our road-riding
counterparts, but you don’t want to be
leaving power on the table with a saddle height that is too low or too high.
Put your riding shoes on. Position
your cranks at the 12 and 6 o’clock
positions. Raise your saddle until the
heel of your shoe barely touches the
lower pedal (the one at 6 o’clock). At
Heel on pedal Ball of foot on pedal