Gmod technical help? I need some support with a rock crawler build

So in gmod, all my tires on my custom built vehicles bounce like crazy and have no grip. Ive tried using jalopytire, jeeptire, and Tibbles Advanced tire. None of them seem to work. Here is the dupe if you want to check it out.

oldguy mode engage

Back in my day traction potential and phys strength was almost directly linked to a props weight. Higher the weight, stronger the phys properties.

a box with boyant properties but a weight of 1 will sink like a rock, but the same box with a weight of 1000 will float like Christ.