Let's start our pre-trip with the steer tires. This is need to be the same size and type. This is very important so we do not run into steering problems.They can not be recapped or regrooved. The steer tires must have a minimum of 4/32 inch of tread in all the major grooves. There should be no tread separation, cuts, cupping or bulging anywhere on the tire. You must check both sides of the steer tire; not just the outside.
The drive tires and the trailer tires are different from the steers. They still need to be the same size and type. They can be recapped or regrooved. They must have a minimum of 2/32 inch tread in all the major grooves. Like the steer tires, the drive and trailer tires should have no tread separation, cuts, cupping or bulging anywhere on the tire. Do not forget to check both sides of every tire. Make sure you have no more than 3 inches of clearance between the dual tires and no debris.
The trailer tires need to be checked for flat spots as these can occur when the trailer is turned sharply and the tires on one side do not roll. The flat spots can also occur when the trailer brakes do not release and the trailer is 'drug' a short distance. This is more likely to happen in the winter when the trailer has been on wet roads or through a partially frozen water puddle and the brakes freeze on. One way to take care of this is to back the trailer up a couple feet before you take off down the road. If the trailer is against something, pull it away from whatever it is against, then back it up a short distance. This will usually release the brakes. You can also put a chalk mark on the tires and make sure they are rolling. Do this on both sides of the trailer, front and back tire. Use your mirrors to make sure the tires are rolling before you get on the road.
The rims need to be secure not cracked, bent, broken and round. There can be no man-made welds. If the rims are aluminum, look for white powder, If the rims are steel, look for rust marks. Both of these could indicate a loose lug nut. If you find a lug nut that is loose, call your shop to have it fixed. It takes about 400 pounds of pressure to tighten a lug nut securely.
Check the valve stem to make sure it is centered, not touching the wheel, has a cap on it and it is tight. The tire pressure is usually between 100 and 110 psi and is checked with a tire gauge.
We can check the hub next. It needs to be secure, not cracked, bent, broken or leaking. All the bolts are there and they appear to be tight. If the hub has a sight glass, make sure the oil is the proper level. If you do not have a sight glass, open the cap and make sure there is at least one inch of 90 weight gear lube in there. Use your finger and then clean your finger with a paper towel or grease rag.
There needs to be a mud flap on the back of the drive tires and the trailer tires. Make sure it is snug to the brace, not broken or missing. You also need to make sure that it is about 3 inches off the ground. If it drags the ground you can lose it and DOT does not like missing mud flaps.