RV Weight Part 3: Suspension Upgrade
So, we know exceeding RV weight ratings is a bad idea. We know how to weigh our rig. Now let’s talk about one potential solution to overweight RV issues. The Toaster recently got an axle upgrade, and it wasn’t as expensive as I had feared…but it wasn’t as easy as I had hoped, either. Here’s what happened.
BTW this info should all be applicable to travel-trailers too (or any other trailer, really) – not just fifth-wheels.
This is the third post in a series about towable RV suspensions and weights:
As mentioned in my last post, the Toaster had a weight problem. You know how it is, one day you wake up, and holy shit, you got fat! WTF happened?!? That’s how it was with the Toaster. Faced with this ugly reality, we had to look at our options, which were:
- Do nothing and hope: We could just keep driving around without changing anything. While being very attractive on account of being free, this would definitely work for a little while, and then stop working in a totally unpredictable and inconvenient way. Possibly also a very expensive and destructive way. This was a non-option for us.
- Ditch our stuff: This is still free…hell, it could be cash-positive if we sell things on eBay…but our axles were overloaded by hundreds of pounds. A T-shirt weighs like 0.1 pound. Our outdoor gear is awesome, in part, because it’s so lightweight. So getting rid of enough stuff to get back within ratings would have meant offloading a LOT of things – things we use pretty often. The Toaster’s situation is that we consumed a lot of our “payload” capacity with the extra insulation, batteries, solar equipment, and other improvements we made during the rebuild. The things we actually loaded into the rig are pretty light compared to what it could originally carry. Offloading our stuff would be trimming fat from already-lean meat.
- Cut back on how much food we carry: Honestly, the food is probably the thing that made the difference between our (acceptable) pre-departure weight and our actual on-the-road weight. We carry at least a week’s worth of fresh groceries (and could probably live another week on what else we’ve got on board). Both of us basically only bother staying alive so we can keep eating (which, we know, is the reverse of how it’s supposed to work). So if you know us, you know the answer to this one is: “Fuck no!”
- Increase the Toaster’s capacity: This is the only option that costs money, but it’s the one we chose. The involves completely replacing the existing suspension with a higher-rated one which can handle the load. This is something we discussed doing during the rebuild, but wanted to see if we could get by without doing it. Apparently, we can’t.
- The big one, which you all saw coming: Lithium batteries. LiPo batteries are far lighter than the wet-cell lead-acid batteries we have now, and converting to an equivalent Lithium battery bank could save us nearly 400lbs. But this is a major undertaking in both time and money, so we didn't opt for this yet.
Normally, choosing the only option that actually costs money is not like us. Why’d we do it?
- The vast majority of our weight comes from our (essentially) permanent mods to the trailer. We’re pretty sure we could have freed up maybe 200 lbs. by getting rid of our personal excesses in clothes, gear, and housewares, but it seemed wrong to prune back so much stuff when it wasn’t really the stuff’s fault that we were overweight. This isn’t a great reason but it is definitely how we felt. The next two reasons are the ones that really sold it, though…
- The existing suspension was already 15 years old, and pretty bagged out. We could hear it click and pop when making tight turns, and as with any used RV, it’s best to assume it was never taken care of by the previous owners. Also, the existing brakes sucked. Like, suuuuucked. So we were coming due to do major work on our undercarriage already. New brakes, links, springs, and tires…that’s only a pair of axles and a set of wheels away from a totally new suspension.
- Doing a suspension upgrade presented two major opportunities:
- Adjusting the trailer’s ride height (it was riding nose-high, mentioned here)
- Over-rating the suspension to give safety margin on shitty roads, which we do tend to use frequently. This was especially germane because we intended to spend the summer in the Yukon, which is not known for velvety asphalt.
So, we decided to go for an all-new suspension, with higher capacity than our current pair of 3,500 lb. axles. What we didn’t realize, is exactly how big of a change that would end up being…
GETTING BIG BOY PANTS
With a combined capacity of 7,000lbs, our old axles were a few hundred pounds overloaded. So I figure, go from two 3,500lb. axles to two 4,000lb. axles and we’d cover it. But that is NOT how it works!
The important thing to remember about a suspension system is that it is just that: A system. As such, it is only as good as it’s least-capable component; this is a weakest-link situation. I have heard some people talk about putting higher-rated springs onto their suspension...if their axles, brakes, and tires aren't also rated for more weight, all that accomplishes is ensuring that the eventual failure will not be in the springs.
While it would have been possible to re-spring our suspension with 2,000lb. springs (4,000lbs. per axle), the axles, hubs, and tires would still have only been capable of 3,500lbs. So we needed to step up all those components, too. What we didn’t know is that the 3,500lb. axles we had were basically the biggest thing available out of the range of lighter-weight options. The proverbial big fish in a small pond. So increasing the capacity meant not just “kicking it up a notch”, but taking things to a whole new level. The next-larger size axles would be…6,000lbs. Each. Bam!
These 6k axles would have 6k-rated hubs on the ends of them, which is awesome because it meant the brakes would be sized to stop a much larger trailer…but it also meant the bolt pattern on the hubs would be beefier. Our old rinky-dink 5-on-4.5" wheels would not be re-usable. The new hubs would have 6 bolts, on a 5.5” bolt circle. So we would not be able to re-use any of our old stuff, not even the wheels. On top of this, our old tires were load-rated to match the 3,500lb. axles, which meant they would not be suitable for use on the new ones. We would need load range “D” tires (minimum) for our new setup. This might all sound like horrible news but it was actually kind of a relief: The old tires were prematurely worn due to being overloaded, so we needed new rubber anyway. And I always hated those white rims.
So after a long spell in the Utah desert, we found ourselves passing through Salt Lake City, and thought that would be a good time to look for a trailer shop. We were not going to an RV dealer for this work (we have a poor opinion of RV shops in general, sorry if you love yours but we can’t afford and don’t trust ‘em). But as it turns out, a lot of “trailer shops” are not used to working on “small stuff” like RVs. They generally work on industrial trailers, semi-trailers, and big equipment haulers, but RVers take their stuff to RV dealers. It’s all just trailers, though. There’s no reason to give RVs special treatment -- or pay RV dealer shop labor rates. So I talked to a lot of trailer shops on the phone who weren’t too interested, or who – I could tell – didn’t do this very often. Eventually I came across D&A Truck & Trailer*, who impressed me by being conversant on the subject of RV suspensions, and were willing to email a quote based on my measurements, without pulling the whole “we’ll have to see it first” thing (when you live in your rig, spending a day showing it around to a variety of shops just to get quotes is not desirable).
D&A had a good relationship with a local trailer-parts manufacturer. I knew this not because they said so, but because I called the manufacturer to double-check part numbers and availability, and they recognized Todd, my sales rep at D&A, by first name. These would not be Dexter Axle parts like our original suspension…but this is one of those areas where name-brands are just not important. Trailer technology is ubiquitous, very well established, and – let’s face it – not fucking rocket science. The parts are nearly all interchangeable across manufacturers, unless you’ve got some high-end proprietary system. Our plain old leaf-spring rigging dates back to horse-and-buggy days, so we were not concerned about paying top dollar for name brand. D&A quoted us $2087 for all-new suspension plus 5 new wheels with rubber, and we committed to getting it done. I was relieved that it wouldn’t cost more.
*We do not have any arrangement with D&A and they have no idea about our blog.
CUT TO THE PANTS
I guess the silver wheels don't look a whole lot different than the white ones. But the larger tires do look a little better!
Here’s what all D&A did:
- Put the Toaster up on jacks and removed all the old suspension. They then ground off the old suspension hangers, which were not spaced correctly for the new springs.
- Per my request, they welded on lengths of 2” square tubing to the bottom of our frame rails.
- The new spring hangers were welded to the square tubing.
- Painted the bare metal and welds with rust-stop.
- The new suspension was bolted up to these new hangers, and the new wheels were installed.
D&A did actually make a mistake with the installation. It’s kind of interesting – especially if you’re thinking of doing this yourself – but a bit much to get into in this post. The short story is that they took responsibility and fixed it without us having to make a fuss or pay for it, but it's still a good reminder that there is no substitute for being an informed consumer. Look for a future post with details on that.
The 2” tubing, unsurprisingly, added 2” of ride height to the Toaster. In addition to this, the new tires have a taller sidewall than the old ones (intentionally) and added ½”. The new springs also rode a bit higher since they weren’t worn out like the old ones, so with all that the Toaster got about 3” taller. This is how we addressed our nose-high issue mentioned earlier. “Why not just flip the axles” you may ask? Well, I initially asked for that but D&A advised against it since it would have added at least 5” – probably more like 6”…which is kinda a lot. We took this advice seriously because it was coming from a guy whose pickup looked like this:
If HE thought it was gonna be too tall, then dammit, it’s too tall! The Toaster already “bumps its head” in many places we like to go, so jacking it up that far was not appealing. There is also some question of stability on the highway and in crosswinds, though it was mostly the clearance question that did it for us. The 3” we picked up in this upgrade was enough to solve the slight nose-high issue we had before, but kept us (barely) under 12’ tall. So hopefully, this kind of thing won't happen to us:
Another bonus to the lift is that it bought us a couple extra inches of bed-rail clearance. If you’re not familiar with 5ers here’s a little explanation: Since the trailer overlaps the back of the truck, it has to have a gap between the underside of its “nose” and the sides of the pickup bed. That’s the bed rail clearance.
Generally, you can’t change this without making either the truck or the trailer (or both) ride improperly; it is what it is, for the rig you’ve got. 5ers are actually shockingly good at navigating lumpy roads, but this is their Achilles’ heel. When the truck twists one way and the trailer twists the other, you run out of space here really fast.
It doesn't take much unevenness in a road to have a pretty big impact. The two photos above were taken AFTER our upgrade, on a pretty tame gravel pull-out from a paved highway, not some wild backcountry track. We had about 6” clearance before – generally considered totally adequate for on-highway rigs – but requiring frequent finesse if you’re a boondocker. For those who don’t know us: “Finesse” is not really our strong suit (neither is “tact”). With the new setup we’re up to 8” clearance and it makes a huge difference. More would have been awesome, but it’s amazing how much difference those 2” have made so far. I can back in tighter circles, and go through deeper ditches without denting anything. That’s with a transfer tank and toolbox, and no slider hitch! Now we can park in even stupider spots than usual…but we still have to pay attention.
THE MOMENT OF TRUTH
Having done this upgrade, we headed for Missoula to keep an appointment. We ironed out the aforementioned mistake once we got there, and then as we left town enroute for the Yukon, we hit a scale to check out our situation. Here’s what we got (hit this link to cope with the acronyms):
|Measurement||Original Equipment Weight [lbs.]||Upgraded Equipment Weight [lbs.]|
Unsurprisingly, we now have no problems in the GAW department, since our axles are now rated to a combined 12,000lbs. But the trailer got 500lbs. heavier. This registers as 460lbs. on the axles and 40lbs. on the pin. Some of that is because we had about 15gal. of greywater for the second weighing, vs. empty greywater tanks for the previous one. Also we had a full load of groceries the second time. The 15 gallons of greywater would weigh about 120 lbs., plus maybe 50 lbs. for groceries, which means the new suspension components added around 330lbs. to our rig. Honestly, I had forgotten to consider this. Nearly doubling the capacity of our suspension did come with a weight penalty.
To follow-up on the nose-high issue, I paid for one extra measurement on the scales during our last visit. After our first pass (truck + trailer), I rolled the rig forward just a couple feet so that each of the trailer’s axles were on a different pad. I wanted to know how the weight was split between the two. This was a little tricky to figure out because unfortunately the rear axle of the truck remained on the same pad as the front axle of the trailer. So that pad’s weight was 9860lbs. From the prior weighing, I knew the truck’s rear axle was supporting 6060lbs. That meant 3800lbs. (9860-6060) were on the front trailer axle. The rear trailer axle was on a pad by itself and registered 4000lbs. even. This works out to a 49% - 51% split and leaves me pretty satisfied that the weight is distributed properly and the trailer is sitting level.
Another way to check this would have been to measure from the ground up to the frame rails at both the front and the rear of the trailer and compare the values. That's a useful way to find out how much you need to raise/lower the trailer to fix the tilt, but doesn't really tell you how far off the weight distribution is. If your dual-axle rig is not riding level, and you're not in a position to alter that, i encourage you to take this extra measurement to ensure that neither of your axles are individually overloaded.
WHERE DOES THIS LEAVE US?
I wish I could say everything’s perfect now. Unfortunately one issue remains – the GVWR of the trailer itself. Aside from the question of axle rating and weight distribution on the kingpin, the frame of the trailer has a weight capacity too, and for that reason the total weight of the whole thing needs to be within the nameplate GVWR. According to the original sticker that was on the trailer before we tore it down, the Toaster is exceeding that rating. This means I can’t be an asshole to people with overweight RV’s, because we’re (still) one of them. Hey, we never said we’re perfect…
Maybe the Toaster’s frame is actually rated higher but the manufacturer down-rated the rig because they wanted to save money on the lighter-duty axles. That would be nice…but it’s hard to imagine Fleetwood paying for a beefier frame than they absolutely had to, and then slapping shitty axles on it. So exceeding our GVWR is still not cool. What can we do about it? Well, reduce weight. That brings us back to the list at the beginning of this post.
All that work and we're right back where we started, huh? Not exactly: We have one problem left but we started with two, so it's better than having done nothing. And driving the Yukon roads, we are very happy to feel confident that our trailer's wheels won't fall off!