When we had our suspension replaced, the shop made a mistake. The good news is that we caught it quickly, and the shop stood behind their work and got it fixed at no cost to us. But I believe things only ended well because of our persistence. If you are considering having work done on your own suspension and want to be more familiar with some details, I hope you will read this post.
This is the fourth (and hopefully final) post in a series about towable RV suspensions and weights:
We do a lot of work ourselves. So maybe our expectation is unrealistic, but when we pay a shop to do work, it’s because we lack (at least) one of the following:
- The tools, equipment, or facilities to do it correctly / safely
- The experience or skill to do the work, and do it well
- The time or patience to do it ourselves. (rare)
- The ability to tolerate the expense or delay of mistakes
When we do have to use a shop, we research our options to be sure we are getting what we pay for, although that can be hard when you’re always in a new area. We ask around for referrals (and then take them with a grain of salt), look at customer reviews online, and pay attention to how professional the shops are when we’re calling around for quotes. Ideally, this would be enough. A customer should be able to rely on their shop to help them decide what they need done, and then make it happen – without having to know anything at all about the subject.
But that’s just not how it is. While some shops are deliberately unscrupulous, I’ve found most to be well-meaning but misguided – especially when it comes to doing work that is not “normal”. Everybody’s got a comfort zone, and it’s fair to say that nothing on our trailer is within it. One guy glanced at our trailer and flatly refused to work on it.
Then there’s “honest mistakes”. Mistakes are okay, they happen. I made like ten mistakes just this morning. If D&A Truck and Trailer had simply made a mistake and then fixed it, I would have a lot less to talk about here. But we had to be informed enough to call them out on their mistake, and that’s why I’m writing this up.
OKAY SO WHAT HAPPENED ALREADY
D&A had our trailer ready at the end of the day, on time, and within their quoted labor figure. That does not happen very often! So I was initially very happy. We hitched up and checked out how the trailer was sitting. It was a little nose-low, but that was expected – the hitch in the truck bed needed to be adjusted upwards to match the lift on the trailer (this is where we got our extra bed rail clearance from). But something was off. Looking at the suspension, we could see that the equalizers were not resting level, as they should when the trailer is on flat ground. In fact, they were canted all the way to one side.
When we pointed this out, the head tech (the fella I mentioned before with the super-lifted truck) said something about how the suspension just needed to “settle in”. He said we should drive it around a bit and then check to see if it’s still doing that. That didn’t seem right to me, but the shop had impressed me enough in every other way, that I decided to listen. After all, everything I knew about trailer suspensions had come from a week of googling, whereas this shop had been repairing trailers for 25 years. Also, we had already been in Salt Lake for much longer than we wanted, and had only a couple days before we needed to be in Missoula. So we left.
The first thing I noticed about the new suspension was that the trailer stopped wonderfully. I had to completely reset the brake controller to keep it from locking up the tires! But once I did that, I noticed that the trailer was bucking the truck pretty hard in stops, and incidental dips in the road caused it to bounce the back of the truck. It never did any of this before (5ers are very comfortable to tow when set up right). Then we opened the windows for some air and we heard it: BANG, SLAM. Going slowly over something like a shallow speed bump, or even some dips on the highway, suddenly all these new, loud noises from the trailer. That is definitely not right! If you know any engineers, you know how we get when we hear unexpected noises from our equipment…well, there’s a reason for that!
When we got to Missoula, I got my tape measure and the suspension manufacturer’s spec sheet, and checked the installation. By this time – only 550 miles of driving – there was already damage and wear on the suspension components.
Part of the work D&A had to do in our suspension upgrade was to weld new hanger brackets to the trailer frame. Check out this page for a little leaf-spring anatomy lesson (I am a big fan of etrailer.com as a good reference for towing information).
The hangers need to be the correct distance apart to match up with the springs being used. The shop knows this. Our job was a little unusual because I requested lighter-weight springs on our suspension. These lighter springs were longer than the standard springs, so the hangers needed to be welded on about one inch farther apart than “normal”.
This is not typical, but it’s far from “weird”. I had already confirmed this setup with the suspension manufacturer, just to be sure. Under-springing is done all the time; it’s why I cautioned in my weighing post that you must check the ratings of all components, not just the axles. It’s something the shop should have taken in stride without trouble.
But they didn’t. The hangers were spaced for 3000lb. springs.
Although D&A had installed the correct 2000lb. springs, they had welded the hanger brackets at the (shorter) spacing for 3000lb. springs. This difference of just under an inch caused the whole linkage to jam up on itself. The way suspension links work together requires that they move smoothly through their range, without rubbing against themselves. Watch this video to see footage of suspension in action, and that will be pretty clear (skip to 1:33):
This setup could not do that. The equalizer could not sit level at all – it had to be pivoted all the way one direction or the other, and even then it was pinned against the links around it by the springs. This meant that our trailer effectively had very little working suspension, and that when it did move, it was only to slam the equalizer between one extreme or the other, which caused the shackle straps to rub the hanger brackets. BLAM!
SO, ISN’T THIS IS ALL MY FAULT?
Why not just use the normal springs? Why do I have to be such a pain in the ass all the time? Why can’t you just keep it simple, Jerud!? Because stronger springs are stiffer, and that affects the ride. Too-stiff springs make for a harsh ride and can turn even baby-butt-smooth tarmac into a jittery rumble. This is why pickup trucks drive like shit when they’re empty and smooth out with a load; they are sprung for a “manly” payload of mulch or gravel (just like in the commercials), not a bag of groceries. When it comes to suspension, yes, your gear has to be strong enough, but it also should not be too strong. It’s a question of correct sizing for dynamic performance, not just brute strength.
So even though the axles, brakes, hubs, and wheels would be capable of carrying 12000lbs. all together, I asked for 2000lb. springs instead of the 3000lb. springs that would normally match up. Two springs per axle means 2000lbs. x 2 = 4000lb. capacity per axle; 8000lbs. capacity for the two axles combined – which is close to, but still several hundred pounds over, our actual axle load. The “normal” spring rating would be a full 50% higher than that. The lighter springs would give us the best ride.
Getting it fixed
Todd was my contact at D&A and he was very reasonable about everything when I called him up. But he also wasn’t going to just take my word that the install was wrong. I can’t blame him; he barely knows me. So we had to take the trailer to a local shop to evaluate. Todd originally proposed that we go to the local RV dealership, but we pushed back on that. With someone else paying their high labor rates, we’d be fine letting an RV dealership do “RV-type” work (while watching over their shoulder), but we have little faith in their knowledge of suspension hardware, and certainly no faith in their welding ability (which I expected would be needed). We found a welding shop in town that did trailer work, and Todd agreed to work with them.
At the shop, the foreman quickly confirmed that the hangers were in the wrong place. Except he didn’t say it that way; he said that the springs were the wrong size. I went around and around with him on this, but he was convinced that the 2000lb. springs were not adequate for the trailer’s load, based only on the gross (total) weight of the trailer. This is wrong. The axles only need to support the weight that is not already supported by the truck at the kingpin. Yes, during driving, the weight shifts and sometimes the axles carry more – but also sometimes they carry less. This is accounted for in the spring design and ratings. It’s the same reason that the tires on a vehicle don’t have to be capable of supporting the entire vehicle’s weight, just their quarter of it.
In most cases, the conservative approach saves you from doing math, accounts for the customer’s probable mis-loading (or over-loading) of their trailer, while doing little harm. Because of the big intervals between axle ratings, it often won't even make any difference in the equipment you choose. In our case, there was a potential difference...but I can see why it’s so commonly believed.
All the proof I need for this is right on our trailer’s original rating plate. The original GVWR was 7900lbs., and each axle was rated 3500lbs. Clearly, the manufacturer is assuming a minimum of 900lbs. will be on the tongue, so that no more than 7000lbs. are carried on the axles. That’s less than 12% of the GVW -- not even the correct weight distribution -- so they were assuming some user error, too. But you just can’t tell some people.
And this is what I had to accept, as the morning wore on. This guy thought he knew what he was talking about, thought my configuration was inadequate. And he wasn’t the only one. The more places I called, the more I ran into this approach. So I did what engineers have done for centuries: I gave up. I accepted that I have to live in a world filled with people who don’t know what I know, and generally have no reason to believe me. Over-springing the suspension would not be unsafe, just not ideal. Which is a hard pill for people like me to swallow (it won’t be optimized?!?!) … but sometimes you just gotta.
Here’s one reason I was okay with giving in: Let’s say we get in an accident. The insurance company, never willing to pay out unless they absolutely have to, gives the wreckage to some local shop to check out, and they discover the springs are rated below the rest of the suspension*. The shop, thinking they know what they’re talking about, reports back that the springs were undersized…and now we get nailed with liability, or at the very least lose the ability to claim no-fault in the accident.
So we decided to have the Missoula shop swap in 3000lb. springs (along with replacing the damaged shackles). The springs were readily available, the work could be done that afternoon without welding, and it would solve our problem quickly. Yeah, the Toaster would ride a bit harsher than it had to…but that wasn’t going to ruin everything. And I wouldn’t have to go through this infuriating physics lesson again. Unless I wanted to write a post about it…
* Okay, admittedly, I’d be surprised if they would actually be clever enough to notice, but I do have fantastically bad luck.
THE MORAL OF THE STORY
D&A paid the bill to correct the work and we got our trailer back that same day. We hitched up and the equalizers sat nice and level. The trailer rode and pulled well, made no noises, and things were good. We headed on to the Yukon, land of gravel and potholes, and things are fine.
But it could have gone differently. If we had just headed down the road as D&A suggested we do, not only would we have a lousy drive with the trailer riding so badly and our stuff bouncing out of cabinets, but it would not have been long before a shackle wore too thin and broke. Probably in the middle of nowhere (and “nowhere” takes on a whole new meaning in the Yukon).
It pays to be an informed consumer. Even though it’s a pain in the ass. We should never have left D&A’s shop in the first place, and we’re a lucky that they still took care of the mistake as they did – I suspect many other shops would not. I’m sad because I was otherwise quite happy with their work – everything else they did was good and professional – but they should never have let us off their lot with such an obvious problem. They should have been the ones to notice it when we hitched up, not us.
If you’re considering suspension work for your trailer, I hope this was useful information. And if you have any additional insight you’d like to add, please share it in the comments!