# How do you convert studs to angles?

Not sure if I picked the right title for this one. I have a basic car chassis that uses bodyforces to give the chassis suspension, and welds to attach the wheels to the chassis. But I have one problem… and that is, the equation that I use to rotate the wheels is not correct, causing the wheels to spin slightly faster it should.

Here is the equation that I use to get the speed:

``````local velocity = mainCarPart.Velocity:Dot(v.CFrame.LookVector) * dT -- dT means:  delta time (or dt for short)
``````

Here is the equation I use to put the velocity into cframe.Angles:

``````weld.C0 = weld.C0 * CFrame.Angles(math.rad(-velocity * 90), 0, 0) + Vector3.new(0, -(The_Distance_Between_The_Corner_Of_The_Vehicle_And_The_Ground - (wheel.Size.Y / 2)) - weld.C0.Y, 0)
``````

For some reason, the wheels spin slightly faster then they should be. Can someone please help me get this fixed?

And if this is not enough info, then please let me know!

Maybe this will help? This is a Khan Academy video on the relationship between angular velocity and linear velocity:

1 Like

Dividing this: `local velocity = mainCarPart.Velocity:Dot(v.CFrame.LookVector) * dT` by the wheel’s radius apparently fixed the problem.

Thanks for your help though @Crazyman32