tires limit
If you have the tags IE 30,000 and the tires ( max weight stamped on the tire) and are under both of these you are legal in the commercial zone) Kc and I assume St Louis) Outside these special zones it gets complicated as far as bridge tables etc. This is basically right for practical purposes.....many exceptions. On the cdl you basically need one for a lot of reasons you may as well get one. I would recommend going to a scalehouse and talking to them.......in your personal vehicle. be honest and they'll help. Phoning is a waste of time. good luck
