robert - trek alpha 23

8/10/2019 Robert - Trek Alpha 23

1/24Bike Fast Fit Ride Faster and Longer 1

Bike Fast FitTitle Trek Alpha 2.3Rider RobertRecorded 07 Dec 2014 22:39

Angles and Measurements

Arm Angle 159,3 deg Arm Angle 159,3 deg

Brake Levers 3,1 cm Foot Angle 3,6 deg

Forearm Angle 15,7 deg Frame Reach 457,6 mm

Frame Stack 579,1 mm Handlebar Angle 28,1 deg

Hip Angle 121,8 deg Knee Angle Max 146,0 deg

Knee Angle Min 76,9 deg Knee Over Pedal 5,7 cm

Projected Frontal Area 0,000000 m! Seat Over Handlebars 16,1 cm

Seat Tube Angle 69,5 deg Shoulder Angle 93,4 deg

Shoulder to Handlebar 11,4 cm Torso Angle Climbing 43,6 deg


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Bike Fast Fit Ride Faster and Longer 2

Gridlines Gridlines

Angle from Vertical 41,6 deg Calibration 99,5 cm


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Arm Angle

Arm Angle 159,3 deg

Arm angle for road bikes is the angle formed by the shoulder, elbow and wrist with

hands on the top of hoods.

Arm angles are typically between 150 and 160 degrees on road bikes. This range of

angles provides good stability and load distribution as well as helping dissipate the

shocks of bumps. If your elbows are locked, you are too far away from the bars.


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Arm Angle

Arm Angle 159,3 deg

Arm angle for road bikes is the angle formed by the shoulder, elbow and wrist with

hands on the top of hoods.

Arm angles are typically between 150 and 160 degrees on road bikes. This range of

angles provides good stability and load distribution as well as helping dissipate the

shocks of bumps. If your elbows are locked, you are too far away from the bars.


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Brake Levers

Brake Levers 3,1 cm

Distance between the brake levers and the arm or handlebar drop.

Road:Road bike brake lever tip should be in line with handlebar drop.

Mountain:Mountain bike brake levers should follow the arm angle.


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Foot Angle

Foot Angle 3,6 deg

Foot Angle is the angle formed by heel, toes and a horizontal line when pedal is in

horizontal or 3 o'clock position.

In the 3 oclock position of a normal pedal stroke, the typical foot angle range is 7 to

15 degrees with respect to the ground. Excessive toe pointing stresses calve muscles.

Excessive heel dropping forces quads to do more work in the power phase of the

pedal stroke.


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Forearm Angle

Forearm Angle 15,7 degForearm angle for aero bars is the angle formed by elbow (lateral epicondyle of the

humerus), the center of the wrist and a horizontal line.

Forearm angles are typically 0 to 20 degrees.


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Frame Reach

Frame Reach 457,6 mm

Frame reach is the horizontal distance from center of bottom bracket to top middle

point of head tube. Frame reach is typically measured in millimeters.

To measure Frame stack, place the vertical line through the center of the bottom

bracket (crank). Place the measuring point on the top middle point of the head tube.

The head tube is where the front fork passes through the frame.

Frame stack and frame reach are bike industry distances to describe a bike's actual

geometry. These numbers are important because they remove confusing bike sizing,

frame dimensions and bike geometry and standardize a bike frame fitting parameter.

Using frame stack and reach a biker is able to determine if a bike frame will fit.


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Frame Stack

Frame Stack 579,1 mm

Frame stack is the vertical distance from center of bottom bracket to top middle point

of head tube. Frame stack is typically measured in millimeters.

To measure Frame stack, place the horizontal line through the center of the bottom

bracket (crank). Place the measuring point on the top middle point of the head tube.

The head tube is where the front fork passes through the frame.

Frame stack and frame reach are bike industry distances to describe a bike's actual

geometry. These numbers are important because they remove confusing bike sizing,

frame dimensions and bike geometry and standardize a bike frame fitting parameter.

Using frame stack and reach a biker is able to determine if a bike frame will fit.


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Handlebar Angle

Handlebar Angle 28,1 deg

Handlebar angle is the angle of the handlebar drop ends.

Road:Handlebar drop ends are pointed down 10 to 15 degrees.


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Hip Angle

Hip Angle 121,8 deg

Hip angle is angle formed by the center of the bottom bracket (BB), the greater

trochanter, and the acromium process (AC Joint)(the middle of the tip of the

shoulder).

Triathlon/Time Trial Bikes:Aero bar height relative to the saddle determines the

hip angle. Optimal hip angle is 95 to 105 degrees.


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Knee Angle Max

Knee Angle Max 146,0 deg

Maximum knee angle is measured when the leg is at the bottom of the stroke and the

foot is horizontal. The angle is determined by the greater trochanter of the hip (femur),

the lateral condyle of the knee (femur), and the lateral malleolus of the ankle (fibula).

Knee angle is adjusted by raising or lower the seat.

Road:A seat height resulting in a maximum knee angle of 145 to 155 degrees is

optimal for most road bike riders.

Triathlon and time trial:A seat height resulting in a maximum knee angle of 143

to 155 degrees is optimal for most riders.

Mountain:A seat height resulting in a maximum knee angle of 146 to 150 degrees

is optimal for most mountain bike riders.

Proper saddle height and knee angle is important for the most efficient transfer of

power to the pedals. A low saddle results in low knee angles and can result in pain in

the front or sides of the knee. A high saddle results in high knee angles and can

result in pain in the back of knee, hamstrings and achilles tendons.


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Knee Angle Min

Knee Angle Min 76,9 deg

Minimum knee angle is measured when the pedal is at top dead center (12 o'clock).

The angle is determined by the greater trochanter of the hip (femur), the lateral

condyle of the knee (femur), and the lateral malleolus of the ankle (fibula).

Avoid a minimum knee angle of less than 70 degrees. Angles less than 70 degrees

can put excessive stress on the knees and lower back.


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Knee Over Pedal

Knee Over Pedal 5,7 cm

Measure horizontal distance from tip of knee to pedal axle with crank forward and

horizontal.

Bike fitters typically recommend the front of the knee be flush with the front of the

pedal spindle. Taller and long-distance riders typically move the knee up to 1 inch (2

cm) behind the pedal spindle. Triathletes and time trialists sometimes adjust the

saddle so the knee is forward of the pedal spindle.

Knee over pedal measurement is changed by moving the saddle fore or aft.


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Projected Frontal Area

Projected Frontal Area 0,000000 m!

Projected Frontal Area is the area of the rider and bike when viewed from the front of

the bike.

Aerodynamic drag is the most resistive force on the cyclist when cycling on level

ground at speeds greater than 30 mph (50 km/h). Roughly 90% of the cyclists energy

is primarily expended to overcome this force.

Aerodynamic drag is calculated using the projected area of the cyclist and bicycle

combined ( A, in m!), the coefficient of drag (Cd), air density (p, in kg/m") and the

square of the velocity of the cyclist (v).

Aerodynamic drag = 0.5 x p x Cd x A x V!

The effective frontal area is the product of the projected frontal area (A) and the

coefficient of drag (Cd) and is commonly abbreviated (CdA). Changes to the projected

frontal area usually involve changes in the shape of the combined cyclist-bicycle.

Therefore, to determine how shape modifications affect the drag coefficient, the

projected frontal area must be accurately measured.


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Seat Over Handlebars

Seat Over Handlebars 16,1 cm

Measure distance from top of handlebars to top of seat.

Typical handlebar height measurements:

Recreational:Handlebars about same height as seat.

Competitive:Handlebars about 0 2 inches (5 cm) lower than seat.

Elite:Handlebars about 2 to 4 inches (5 10 cm) lower than seat.

The closer the handlebars height is to seat height, the more power the rider can

produce.

Handlebars lower then the seat provide a more aerodynamic rider profile and best

suited for fast riding and racing.


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Seat Tube Angle

Seat Tube Angle 69,5 deg

Seat tube angle is the angle formed by ankle, hip and a horizontal line when foot is

furthest from the hips.

Seat tube angle are usually included in bike specs, but the real angle or effective

angle is determined by a number of factors. The factors are seat post setback

position, position of seat on the rails, seat and where rider sits on seat.

To calculate effective seat tube angle, find the moment pedal-side foot is the furthest

from the hips. The angle is determined by a line from the greater trochanter of the hip

(femur), to the lateral malleolus of the ankle (fibula) and a horizontal line.

Road:Effective seat tube angles are typically 72 degrees (shallow) to 80 degrees

(steep). Higher effective seat tube angles lower the chest to allow the rider to be

more aerodynamic.

Triathletes / Racers:Effective seat angle closer to 80 degrees are typically for

more advanced triathletes or riders will to bear the discomfort in shorter races.

Effective seat tube angles around 72 degrees are best for longer distance events,

newer triathletes and riders less confident in their bike handling skills.

It is generally accepted the seat tube on a triathlon bike should be placed more

upright and forward than a road bike. The reason is the forward position places the

rider over the cranks further and puts the rider in a more aerodynamic position and

reduces the strain on running muscles.


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Shoulder Angle

Shoulder Angle 93,4 deg

Shoulder angle is measured from the greater trochanter (hip), the acromion (the

middle of the tip of the shoulder) and the elbow (lateral epicondyle of the humerus).

Optimal shoulder angle is 80 to 95 degrees.

Road:Road bike shoulder angle is calculated with hands on the hoods and elbows

bent about 15 degrees. Shoulder angle should be around 90 degrees.

Racers:Some road racers and time trialists prefer a shoulder angle of greater then

90 degrees.

Aero Bars:For bikes with aero bars, aero bars should be placed so rider forearms

represent a column perpendicular to the weight they are supporting. The shoulder

angle measures the angle from the forearm to the hip.


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Shoulder to Handlebar

Shoulder to Handlebar 11,4 cm

Distance from shoulder to center of handlebar drops.

Wider handlebar hand position typically steers more slowly and provides better control

for road biking.

Some riders prefer handlebars wider then shoulder width because wide handlebars

provide them better bicycle control for typical road riding.

Road:Road bike standard handlebar widths are shoulder edges equal to center of

handlebar drops.

Mountain:Mountain bikers handle bar width is a line from the lateral shoulder that

passes through the elbow and the space between the thumb and first finger.


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Torso Angle Climbing

Torso Angle Climbing 43,6 deg

Climbing is typically performed with hands on top of the handlebars. This method

improves the ability to generate power required for a hill climb. Climbing torso angle is

angle formed by the shoulder (greater tubercle of the humerus), hip (greater

trochanter of the femur) and a horizontal line.

Climbing torso angle should be at least 45 degrees.


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Gridlines

Gridlines

Series of horizontal and vertical lines.


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Gridlines

Gridlines

Series of horizontal and vertical lines.


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Angle from Vertical

Angle from Vertical 41,6 deg

Angle between two points and a vertical line.


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Calibration

Calibration 99,5 cm

Designate two points a known distance apart on the video.

robert - trek alpha 23

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