Difference between revisions of "Head Angle Change With Suspension Travel"

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(Head Angle Change)
(Bottom Bracket Height Change)
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==Bottom Bracket Height Change==
 
==Bottom Bracket Height Change==
 
[[Image:Bb-height-change.gif]]
 
[[Image:Bb-height-change.gif]]
 +
 +
 +
[[Image:Bb-Change-with-Trav.gif]]
 +
 
==Mechanical Trail Change==
 
==Mechanical Trail Change==
 
[[Image:Mechanical-trail-change.gif]]
 
[[Image:Mechanical-trail-change.gif]]

Revision as of 17:07, 15 December 2007

According to very accurate calculations that I have done, the head angle will change on a hard tail mountain bike approximately 0.0521° per mm of travel if it has a 1058mm initial wheelbase. The bottom bracket height will change approximately -0.3868mm with each mm of suspension travel.

Different wheelbase bikes will change at different rates.

Formulas

Here are the equations:

  • A12 = Initial Head Angle
  • B12 = Fork Offset
  • C12 = Sagged fork length
  • D12 = Initial Wheelbase
  • E12 = Initail BB Height
  • F12 = Chainstay Length
  • G12 = Wheel Diameter
  • H12 = Fork Compression or extention from sagged

These formulas are not designed to work with 2 different wheel sizes and do not account for tire deformation.

Otherwise, they are perfect.

Head Angle Change

Head-angle-change.gif


Head-Angle-Change-with-Trav.gif

Bottom Bracket Height Change

Bb-height-change.gif


Bb-Change-with-Trav.gif

Mechanical Trail Change

Mechanical-trail-change.gif