Measuring Center of Mass (COM)

[Chimchim]

What is the right way to accurately measure your center of mass? I see a lot of references to COM on the forum and want to make sure measuring the same way everyone else is.

For example, when someone says 3/4" COM, I assume this means their car balances on a fulcrum 3/4 of an inch from the rear of the car. I also assume that this measurement is taken with all the weight, axles, and wheels installed. Are these correct assumptions?

Finally, if anyone has a homemade tool/rig for accurately measuring this, I'd be very interested in knowing how to make something similar.

thanks in advance

[W Racing]

Mar 16, 2010 21:56:09 GMT -7 Chimchim said:

What is the right way to accurately measure your center of mass? I see a lot of references to COM on the forum and want to make sure measuring the same way everyone else is.

For example, when someone says 3/4" COM, I assume this means their car balances on a fulcrum 3/4 of an inch from the rear of the car. I also assume that this measurement is taken with all the weight, axles, and wheels installed. Are these correct assumptions?

Finally, if anyone has a homemade tool/rig for accurately measuring this, I'd be very interested in knowing how to make something similar.

thanks in advance

COM is from the rear axle. You can rest your car on the block and at the point where it tips forward is the COM.

[Wood Butcher Racing]

W is exactly right - the rear axle (whereever it may be)

I check it in the same manner W describes, except instead of the block I use a scrap of wood with the measurements scribed on top of it (based on std BSA wheelbase)
Wheels are a good reference too. The radius is about 5/8".