I need help with my Go-Kart

Hello! I am currently trying to make karts for my racing game. Right now, I am trying to fix a noob kart. However, the wheels fall apart.

Image in studio:

Image in Test mode:

If you can help, please let me know. Thanks, WE

Inside explorer

You need to place welds inside of it

Where to put the welds? I have never made a car in Roblox.

You shouldn’t be using the old hinge surfaces anymore. Switch over to hinge constraints. It might fix your wheels from falling off.