sigma header
home pageprojectsservicescatalogtechgallerycontact
MOI - Moment Of Inertia
Mike Karwath - August 2007
The moment of inertia of an object about a given axis describes how difficult it is to change its angular motion about that axis. Or in simple terms, it can be defined as "how hard it is to bend an object from its original form." In our applications offroad, this MOI is in reference to tubing, or how hard it is to bend that tubing from its current state. This information can be useful when deciding what size and thickness of tubing to use for a rollcage or suspension links. Of course, the higher the MOI, the harder it is to bend the tube. To make this chart even more useful, I have included the weight per foot of the material as well as the area of cross section for reference. Enjoy!
Tubing O.D. Wall Thickness Cross Section Weight / Ft. MOI
         
1.00 .060 0.177 0 lb, 9.632 oz .02
1.00 .080 0.231 0 lb, 12.576 oz .025
1.00 .095 0.27 0 lb, 14.704 oz .028
1.00 .120 0.332 1 lb, 2.08 oz .033
1.25 .060 0.224 0 lb, 12.192 oz .04
1.25 .095 0.345 1 lb, 2.874 oz .058
1.25 .120 0.426 1 lb, 7.2 oz .069
1.50 .060 0.271 0 lb, 14.752 oz .07
1.50 .095 0.419 1 lb, 6.816 oz .104
1.50 .120 0.52 1 lb, 12.32 oz .125
1.50 .188 0.775 2 lb, 10.192 oz .17
1.50 .250 0.982 3 lb, 5.472 oz .199
1.75 .120 0.614 2 lb, 1.44 oz .205
1.75 .188 0.923 3 lb, 2.256 oz .285
1.75 .250 1.178 4 lb, 0.144 oz .341
1.75 .375 1.62 5 lb, 8.208 oz .411
1.75 .500 1.963 6 lb, 10.88 oz .445
2.00 .095 0.569 1 lb, 14.976 oz .259
2.00 .120 0.709 2 lb, 6.608 oz .314
2.00 .188 1.07 3 lb, 10.2556 .444
2.00 .250 1.374 4 lb, 10.816 oz .537
2.00 .375 1.914 6 lb, 8.224 oz .666
2.00 .500 2.356 8 lb, 0.288 oz .736
2.25 .095 0.643 2 lb, 3.008 oz .374
2.25 .120 0.803 2 lb, 11.728 oz .457
2.25 .188 1.218 4 lb, 2.32 oz .653
2.25 .250 1.571 5 lb, 5.536 oz .798
2.25 .375 2.209 7 lb, 8.288 1.01
2.25 .500 2.749 9 lb, 5.68 oz 1.138
2.50 .120 0.897 3 lb, 0.848 oz .637
2.50 .188 1.366 4 lb, 10.384 oz .918
2.50 .250 1.767 6 lb, 0.298 oz 1.132
2.50 .375 2.503 8 lb, 8.288 oz 1.457
2.50 .500 3.142 10 lb, 11.088 oz 1.669
3.00 .120 1.086 3 lb, 11.136 oz 1.128
3.00 .188 1.661 5 lb, 10.488 oz 1.649
3.00 .250 2.16 7 lb, 5.616 oz 2.059
3.00 .375 3.093 10 lb, 8.416 oz 2.718
3.00 .500 3.927 13 lb, 5.825 oz 3.191
         

All information listed on these tech pages cannot be guaranteed to be true or correct. Please be sure to
consult a verified source before moving forward with any modifications based on the knowledge found here.
sigma motorsports
Sigma Motorosports 2009 - All Rights Reserved