Trailer Wheel and Axle Alignment
By Warren Petkovsek
It’s true. Most RVers with towable campers never give a single thought to trailer wheel and axle alignment. I’ve been towing trailers and fifth wheels for nearly thirty years now and I must confess that I’ve never thought much about it either. So what made me think about it now? Check out the
of one of my tires and you will see the cause of my concern. This tire showed a lot of wear on the outside of the tread and there was, in fact, a little bit of cord showing through. 'Time for a set of new tires, for sure. Why buy a whole new set of tires when only one of them showed unusual wear? Oh, I suppose I could have got by getting only one new tire to replace the bad one, but I’m kind of funny that way. It would bother me knowing I had three old tires and one new one. It’s worth it to me to have a whole set of new tires just for the peace of mind. You can do what you want (Be sure to read my article on
Tires for Towable RVs
). But I sure didn’t want to spend a lot of money for new tires and have the same thing happen again so I checked out all of the possible reasons for that kind of tire wear.
Conventional wisdom tells us that overloading the trailer can cause axles to flex and bend which would surely affect alignment. Well, I had just recently weighed my rig and found it to be well within the manufacturer’s weight capacity so overloading wasn’t a concern in this case. Still, weight should be the first thing you check if you see unusual or rapid wear on your tires. I also found out that overloading will generally, but not always cause wear on the inside of the tread because the excess weight will cause the axles to bend upward (like a smile) which causes the inside of the tread to wear. But my tire wear was on the outside edge of the tread which was just the opposite. That leaves us with only alignment to consider.
I live near Beaumont, Texas and I talked to my RV dealer and several other knowledgeable people and I kept hearing about a business called Beaumont Frame and Front End. These folks have been in business for years and they specialize in alignment of all kinds of vehicles including trucks, trailers and buses. I went there one day without the trailer and met a gentleman named Roland who visited with me and told me all about the reasons for trailer misalignment and subsequent tire wear. After talking with Roland I decided that Beaumont Frame and Front End was the place for me to get my beloved rolling home repaired so I made an appointment and brought the rig to them a couple of days later.
I arrived with my fifth wheel as soon as the business opened and Roland and his crew got to work on my rig right away. In our conversations I mentioned to them that I wrote articles related to RVing and that I was thinking about writing an article about trailer wheel and axle alignment. The staff was very kind and cooperative with me and allowed me to ask all the questions I could think of and to take all the pictures I wanted. Let me tell you something. When you ask these knowledgeable folks any questions concerning alignment you had better pack a lunch! They will tell you more on the subject than you want to know. I quickly got into the realm of “information overload” so it was obvious that they knew exactly what they were doing.
The job started with the staff backing my beloved fifth wheel into the large vehicle alignment bay. This doesn’t sound too difficult until you consider that the bay includes a pit where the technicians work. The wheels must go onto some steel ramps that span this pit. I couldn’t bear to watch and I’m glad that I wasn’t doing the backing. They all just smiled at me and said, “We’re not worried. It’s not our trailer.” After having a little fun at my expense the techs got to work. After checking the alignment it was determined that my tire wear was, in fact, caused by misalignment and not overloading. That was a relief.
The techniques and tools that were used were high tech and old school at the same time. There were some space age looking doo- dads (excuse my technical terms) that I really didn’t understand and I didn’t want to find out about them because I was already asking a lot of questions and I probably wouldn’t have understood anyway. Some of the old school techniques included two guys holding up a tape measure and finding the distance between the centers of the wheel hubs. Some of the adjustments were made by chaining down the outside of the axles near the wheels and pushing up on the center of the axle with a hydraulic jack (do not attempt this at home). After releasing the jack they would measure everything again and repeat the process until the correct alignment readings were attained.
I learned that trailer alignment includes toe-in which is simply having all of the wheels pointing in exactly the same direction and camber which is the amount that the wheels lean in or out. Caster is another adjustment that must be set on vehicles, but not on trailers because there is no steering involved. The camber on my trailer was just a little out of spec so they brought that back in line. The real problem was toe-out on the rear axle. The right rear wheel was pointed out a little, but this wasn’t the tire that was worn. The worn tire was on the front axle on the right side just in front of the wheel that was out of line. Roland’s explanation of this made perfect sense. He said that the out of line tire isn’t always the one that shows the excess wear. The tire in front was wearing because it was the one that was working to keep the rig going straight down the road. Hmmmm. That was interesting. ‘Makes sense now that it was explained to me. The point is that you should have all axles aligned and not just the one with the tires that show wear.
The cost of the job at the time of writing was $110.00 per axle. ‘Not too bad really and certainly much better than wearing out more tires and possibly other suspension components. Well, what causes trailer wheels and axles to get out of line in the first place? We need to know this in order to keep it from ever happening again. Roland told me that obviously hitting bumps and potholes really hard could cause misalignment, but that would take a pretty hard hit indeed. More than likely in my case the reason was that the axles were never aligned properly when the trailer was built. This problem is more common than we might think. RV assembly lines surely don’t have sophisticated alignment equipment. They simply measure and drill the holes for suspension mounting brackets which is fine most of the time. I suppose it is also possible for new axles to be less than perfectly straight as well.
Most RVers are “weekend warriors” or otherwise don’t really put enough miles on their trailers for this uneven tire wear to show before the tires need to be replaced due to age or until the trailer is sold. I found the wear because we are fortunate enough to be able to use our rig a lot and put quite a few miles on it. I noticed slight wear early on, but at about 25,000 miles the wear got really bad which caused my concern.
In conclusion I would suggest that everyone who uses a towable RV check their tires for unusual wear whenever you check tire pressure and you should do this often. Be sure that either you or the RV tech check for unusual or uneven tire wear whenever the trailer brakes or wheel bearings are serviced as well. Also, you will never feel misalignment in a trailer like you would in a vehicle that you drive. You just can’t feel it from the driver’s seat so you have to look things over really well. Also please check out my other article on tires and become as knowledgeable on this subject as you can. Alignment problems will cause tire problems which will possibly ruin an RV trip and cost you a lot of money. Keep a close eye on all of your equipment, be safe and enjoy the RVing experience.
Warren Petkovsek has been an avid RVer for over several decades. He lives in Lumberton, Texas with his wife, Myra. A former teacher, band director and professional musician, Warren is now retired from the petrochemical industry. In addition to being a freelance writer he is also a school volunteer, a Texas State Park volunteer and has been a Boy Scout Leader for many years. Warren would be delighted to answer any RV related questions that you may have and would be happy to send you some or all of his other articles. He can be contacted at firstname.lastname@example.org .