## calculating arb wheel rate.

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JakeP
JakeP
2
Joined: Fri Jun 20, 2014 9:45 am

### calculating arb wheel rate.

Hi there im having trouble finding the correct way to calculate the arb wheel rate in n/mm. Does anyone have an equation they trust? Also its tube not a solid bar. Any help would be greatly appreciated. Greg Locock
Greg Locock
179
Joined: Fri Jun 29, 2012 11:48 pm

### Re: calculating arb wheel rate.

oh dear. tube vs solid is D^4=od^4-id^4. The rest is even more boring. Tim.Wright
460
Joined: Fri Feb 13, 2009 5:29 am

### Re: calculating arb wheel rate.

• Find the motion ratio between wheel travel and bar twist angle using either magic or kinematics. Then use it to calculate the bar twist for 1mm of opposing wheel travel.
• Calculate the bar stiffness using either magic or Greg's equations above and use it to calculate the bar torque resulting from the twist angle in the previous step.
• Use the inverse of the motion ratio found above (or some black magic) to convert this torque into a vertical wheel force.
Your wheel rate is then numerically equal to the vertical force that you found.
This will only work if you strictly stick to one system of units (i.e. SI).
Not the engineer at Force India