Body Fit (Angles, Measurements etc.)

Sam Kennedy

New Member
Location
Newcastle
Hi There,

I was wondering whether anyone knew the optimum angles for a proper fit on a bike?
I need to know the best fit for my time trial position, and general road riding.

I'm going to take a side-on photo of me on my bike, I can measure all the angles and stuff in photoshop, I just don't know what the angles should be!

Cheers,
Sam
 

Rob3rt

Man or Moose!
Location
Manchester
For your aero possition

When you take a picture side on, get into your TT tuck possition (i.e. on the tri bars). When you have this picture. Draw a line from the ball of your foot to your hip then from this point to your shoulder, then from your shoulder to your elbow. The angles should all be roughly 90 degree's.

With the pedal in a vertical possition, you should have a 20-25 degree angle in your knee with the pedal in the lowest pedal possition.


The angles should be essentially the same as a proper road racing fit. but rotated around the hip (to avoid closing the hip angle, because with a reducted hip angle comes reduced power output).


Some leeway for personal comfort etc.
 

accountantpete

Brexiteer
boardman-cycling.jpg




This as good as you will see.

Basically the seat is set in neutral so as you turn the cranks you don't emphasis either the upward or downward phase.

When you move the body position forwards, as Mr B has here, this emphasises the downwards phase in order to push a bigger gear.
 

jimboalee

New Member
Location
Solihull
boardman-cycling.jpg




This as good as you will see.

Basically the seat is set in neutral so as you turn the cranks you don't emphasis either the upward or downward phase.

When you move the body position forwards, as Mr B has here, this emphasises the downwards phase in order to push a bigger gear.

Chris spent weeks in the Wind Tunnel at the Motor Industry Research Association to get that position right.
The bike's seat height and setback from the BB ( and crank length ) was decided on an Ergometer in a lab.
 
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