Seat height is determined by pedalling efficiency, and has nothing
to do with being able to touch the ground while sitting in the saddle.
To find the right height - put one heel on the pedal at its lowest
point while keeping your pelvis square on the saddle. Your leg should
be straight. It's a bit high if your pelvis starts to rock with each
pedal stroke. Adjust the height in small increments, 1-2mm at a time.
Too low and you'll only be using a fraction of your potential power
and your legs will burn-out on the smallest of inclines. Too high and
you'll be out of kilter - unable to maintain a respectable cadence
and risk long-term injury.
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A lower seat height allows improved handling during technical descents.
Some riders drop their saddle before losing altitude. The Gravity Dropper
seat post is a natty solution if you're that way inclined (www.gravitydropper.com).
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Have a shifty under your seat. You'll discover a bolt that lets
the saddle slide backwards and forwards on its rails - the central
position is a good place to start. Hop on your bike and spin
the cranks to the horizontal position. Then use a plumb bob to line
up the middle
of your knee cap with the ball of your foot.
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Position your cleats so the pedal spindle sits directly under the
ball of your foot. Then experiment by nudging the cleats (in
1mm increments). Forwards to work your calves and deliver snappier
acceleration. Backwards
for increased long term power output and more endurance.
The Long and Short Of It
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The distance from saddle to handle bars should be comfortable, ie.
not too cramped or over-extended when riding. It's hard to overstate
how important it is to have the right size frame. When comparing different
bikes the critical dimension is the effective top-tube length - the
distance from the centre of the top of the headtube along a horizontal
line to the point where it would intersect with the centre of the seat
tube if it extended that far. Take a surf on the web to check how your
current frame stacks up against other brands.
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Adjustment at the saddle compromises your pedalling position – best
not to do that.
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The effective length can be tweaked with different length stems
but this alters the bike’s handle. Keep within a range of 90-110mm.
Get It Up
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Riser bars, high-angle stems and/or spacers under the stem let
you modify the relative height difference between the saddle and
your handlebars.
Lower bars are better for hill climbing, higher better for descending
and more comfortable on your back. Modern frames with long travel
forks favour a more upright stance – more couch than broomstick – so
your handle bars will probably end up at a similar height to your
saddle.
Body Torque
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Once your basic stationary set-up is sorted it's time to jump on
the beast for some real-world testing. Bad habits, old injuries, tight
muscles and fragile backs can throw a spanner in the works. Do your
knees act weird at the top of each pedal stroke? Maybe your upper body
bobs to maintain your cadence or to smooth out your pedal stroke? You
may need to tweak your set-up or possibly change the way you move.
The Alexander Technique preaches that you can beat your body into submission,
wear hair shirts and practise the correct movement until it becomes
second nature.
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Correct gear selection and therefore a strong, even cadence are
synonymous with good form. 80-90 rpm (higher on the road) should land
you in the same bunch as Gunn Rita. Drills of one legged pedalling
(for 3-5 minutes) teach your body volumes about spinning in fast, smooth
circles.
Spring is the time to re-assess your technique and bike set-up. It's
highly likely that your training-log is looking a little thin - your
hamstrings will have relaxed enough to let you tie your own shoelaces
and test your body in subtly different positions.
Allez allez.
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