Car hauler trailer rear tires bald

My car hauler has recently scrubbed ALL the tread off the rear tires. This spring they looked as good as the fronts, but after a few loan outs and a few trips to the mountains plus the odd trip to the lumber store my rears are bald as a babys backside. I suspect a bent axle or a shifted spring hanger. Can anyone elaborate on how to measure to prove the axle? Anything else I should look for? The trailer is a 7K dovetailed Top Brand. Thanks in Advance, Aaron

several ways, if the tire is totally slick you can use chalk to scribe a line around the tires, otherwise use one of the tread lines, measure the distance between the tread line on both tires, in front of the axle, and again on the back side of the axle, if there not the same, there is a toe in or out problem, usually by somebody hitting a curb ect with a loaded trailer, now take a level and put it against the wheel/ tire, you may have to raise the axle off the ground to take the buldge out of the tire, if so make sure the trailer is level side to side, it needs to be for this to work, with the level standing on end against the wheel/tire, they should be straight up and down, if bowed in at the top the axle is bent usually caused by overloading the trailer or hitting a hole ect fully loaded, then measure the distance between the 2 axle centers, [ where the wheel bearings are] if there different side to side, one of the axles is out of alignment, usually due to wear or bent parts such as spring hangers, rockers ect close inspection is required to figure out just what needs to be fixed, let us know what you find, it is possible, but not likely, to wear the tires on the rear axle by loading the trailer heavy on the front, like a tractor pulled all the way to the front end of the trailer, and sitting between the hitch and first axle, then running at high speed for long distance,

Exactly why I do not loan any of my trailers out, not even to kinfolks. They will tear up your equipment and return it without saying a word about it. Tom

Thanks Eric, I will let you know what I find. @Tom: I am learning this lesson one dent, scrape, tire, axle, ramp at a time.

Aaron

check the hanger bolts before doing the other stuff. It may just need new bolts. Or look for axle shifting marks on the springs where they mount together. I just did a trailer for a friend whos tires would peel off in a couple 100 miles. The center hanger where the 2 springs joined was missing and the 2 axles shifted. We ended up measuring from the rear of the trailer to the center of the wheel hubs on each side to make sure your numbers matched. Good luck.

The correct way to align a trailer axle is to measure the front axle first to see if it's straight. If you just check the axle to axle alignment it may dogtrack. Start by taking off the tires, then measure from the center of the front of the coupler to the outside center of the front axle on both sides. Just remove the cap for this. A little bending of the tape measure is ok as long as you do both sides the same. The measurements should be within 1/16-1/8". Next measure between the axles on the axle ends, this should have the same tollerances. The level thing won't work because the axles are bent to give a little toe-in and camber so they will both be a bit narrower in front and tilt out on top unless they are bent. The springs and equalizers have plastic bushings in them that can wear out if you have enough miles on it, but that usually doesn't lead to alignment issues, only a lowering of ride because the presure is mostly down. If you find an alignment problem and cant see a bent axle or suspension, check where the springs are clamped to the axle, there is a bolt that goes through the spring and into a hole in the axle sadle. If someone hit something they may have sheared off that bolt and the axle may have slid back. You should be able to see if it has slid there. If you have an alignment problem this will be the most likely culprit. You should also check the suspension hangers to be sure they were welded on corectly at the factory, I have seen more than a few that were not welded on square from new and the tire wear doesn't always show up right away because it takes a while for the tires to take a "set" and decide which ones will be the ones to wear out.

Sounds to me like someone had a really low hitch ball and the fronts dug in and just the back axle slid on turns. If the tires are worn the same...not one more than the other I doubt if it's alignment.
I have seen this happen with tires of different sizes also. Little tires wear a lot faster.

I have put a lot of miles on my two fifth wheel RVs. the rear always wear out faster than the fronts. I blame it on squrming on corners. Left rear is always the worst. two rears for one fronts.

The best way i know of is to Bisect it with a tapemasure . Place the trailer up on jack stands to where you can get under it and a rod -pipe straight up and down from the hitch ball socket make up some sort of double washer to go around the rod- pipe to hold the dumb end of the tape or have someone hold it at the same place and take your readings at the end of the axle with tires and hubs off . A little work but you will see real fast where it is out . Myself i have aligned many semi trailers this way .Also look for loose u/bolts and any shifting on the spring to axle as this may mean a broken center bolt on the springs if you have springs.

Don't really want to start a fight here, but the theory that trailer tires wear out because of cornering is a myth. Even tho they leave black marks as you turn, the amount of time spent turning is so little that it would take years of turning to show wear. The reason that tandem and tri-axle trailer tires wear is because trailer axles are made with toe-in to make them trail better. This makes the tires scrub a bit all the time as you drive. And since manufacturing tollerances aren't as tight as car and trucks they are all a bit different so almost always one will push one way a bit and the other the other way, so the tires are always fighting each other as you drive. That is why a single axle trailer will almost never wear out the tires before they rot off.

Check the electric brakes. Probably locking up the rear brakes.

The trailer needs to sit level when hitched to the truck.

I'm betting most of the people you loaned the trailer out to have these modern jacked-up 4x4 1/2 ton pickups, and standard 2-1/2" drop drawbars for their hitch balls.

They're dragging the trailer down the road with the tongue 6" high and the front wheels almost completely off the ground. All the weight goes on the rears, and wears them right out.

Put a straight edge along side your wheels at about the centercap and all four surfaces should touch equally if it is in alignment.