RV Weight Part 2: Visiting The Scales
Before we moved into our RV, I did a lot of reading online. I saw many articles reminding RV owners to get their rigs weighed at scales, and to ensure they were operating within the ratings of their equipment. Seemed like a good idea. Once we got on the road, however, I found that it’s very rare indeed to encounter someone who has actually done it. We, too, passed scales countless times without stopping, because we had someplace to be.
I think there’s two main reasons RVers don’t weigh their rigs:
- It seems like serious commercial heavy-duty type stuff that shouldn’t really apply to RVs, especially since we don’t have to get any special licenses or training. Or in other words, it doesn’t seem like it’s that big a deal. Something only persnickety engineers do.
- Nobody actually tells you how to do it, and scales (truck stops) are intimidating places.
If Reason #1 applies to you, please look at my earlier post about RV weights and loading. If you don’t need to hear my preaching and just want to know what’s up with the scales, read on. Bear in mind that since our rig is a fifth wheel, the specifics here will be slanted towards towable RVs (5ers and travel trailers) However, most of the process will be the same for a driveable RV – only the calculations at the end will be different.
This is the second post in a series about towable RV suspensions and weights:
HOW TO ACTUALLY DO IT
We generally use the CAT scale website to find a facility on our route. There’s probably an app, too (yup). Once you know what to look for, the signs are conspicuous from the highway, so you can easily decide to do an ad-hoc weighing. CAT isn’t the only option, and possibly not the cheapest, but this is one time where I just go for easy.
Configure your rig beforehand. The weighing needs to represent the (worst-case) state you’ll be in while underway. Your “rig” includes tow-vehicle plus trailer, and if you’re in a motorhome, it includes your toad or anything else you're towing. Now make sure everything that you will normally bring with you is packed. Passengers, sports equipment, clothes, and especially groceries. Everyone underestimates the weight of food! Ensure that all fuel tanks are full, all propane tanks are full, and your fresh/grey/black tanks are at their heaviest practical configuration. For most folks, this would be having all grey tanks and black tank full, but freshwater empty (you’re probably not going to drive around with freshwater and holding tanks full). Put everything in the tow vehicle that would normally be there (tools, luggage, pets, family), and ensure that your towing equipment (rear axle airbags, hitch height) is configured as it would be.
Budget 1 hour for your first visit. It really shouldn’t take more than 30 minutes once you know the drill, but if you go at a peak time there are often lines at the counter. I have no idea what “peak time” is, but the last thing you want (especially your first time), is to be in a rush. The steps of the actual weighing should be very close to this:
1. Pull right up onto the scale (assuming it’s vacant). Take a deep breath and drive on in there. The truckers aren’t watching you, and they’re definitely not judging you. They already have preconceived stereotypes about RVers and you’re not gonna change that. Make sure you are facing the right direction, with the kiosk on the drivers’ side (otherwise the results will be confusing and you might screw up the traffic around the scale). The kiosk is waaaay up high — it’s positioned for truckers, not RVs!
2. Start feeling very small and intimidated (I always do).
3. The scale is actually broken up into several separate pads, and to get meaningful results, you need to position your rig on them correctly. As much as I’d enjoy making a little diagram for this, CAT does a great job already, so please just follow their guide.
4. With your rig properly positioned, it’s time for the hardest part: You have to find a way to press that button! I can usually get it with a jump-slap, and I’m no basketball player. You may wish to use a stick, or maybe stand on your running boards while hanging onto the mirror... The buttons have zero tactile feedback so I always wonder if I really pressed it. You just have to wait for the attendant to say something. Sometimes the speaker is good and the area is quiet, and you can understand the attendant. Other times…not.
5. Usually the attendant starts by asking if you want a first weigh, or a re-weigh. Right now, you need to get the first weigh.
6. Next they'll ask for your truck number. You don’t have one, of course, but there’s no point trying to explain. In most cases, they can’t even see you from where they are. So make something up — but keep it short so you can remember it! They just need something to punch into their system to get to the next step. I find that single-digit numbers sometimes make this step awkward (“Oh! Um, seven” sounds to them like “0 1 7”) so try for 2-3 digits. Lucky numbers, zip codes, area codes, etc. work here (but don’t use your ATM PIN, k?). Keep both feet on the scale pad during this conversation, because you want your weight included in the reading.
7. Boom, they just weighed you. There’s no lights or sounds or anything. They’ll tell you to come in for your printout. Drive off the scale and put your rig into one of the truck slots nearby. If you’re towing a trailer, you’re going to have to make another pass, so ask your partner (if applicable) to start prepping to unhitch while you go inside. Make sure you have your license plate numbers (for both tow vehicle and trailer) with you. If you’re in a motorhome and have a toad, bring both the coach and the toad’s license plate.
8. Inside, find the trucker’s counter. There may be a separate counter for regular gasoline and passenger car customers. But if you’re walking in from the scales, most likely you will get to the trucker counter first. You’ll know you’re on track if you’re near the showers and lounge. And also, yeah, truckers will be there.
9. At the counter, say you want to get your scale printout, and give your “truck number” from before. They may ask for your license plate numbers at this point. They also may ask for a "company" name. I haven't yet come up with a response which seems to be universally satisfactory, but some that i've successfully used in the past were "RV", "independent", and "private".
10. You’ll be handed a printout. Pay for the weigh (usually around $10) and you’re all set. If there is a baseball-card-thingie stapled to it, you can offer it to the attendant, in case they want to give it to one of the truckers who is collecting "Supertrucks" cards. I have no idea what the cards do, only that this one guy was pretty happy to get mine.
Motorhomes: You’re done, unless you’re towing something. All that remains is to review the numbers.
Trailer-towing RVs: Time for another pass. Unhitch your trailer and drive the tow vehicle back onto the scales. Park in the same position as before.
11. This time, when you press the button, say you want a “re-weigh”. They will ask for a number again — this is NOT your made-up “truck number” — they want the "Weigh Number" from your first printout. I always get this wrong. Remember to stand on the scale pad again.
12. Head back inside for the second printout. Sometimes the re-weigh is free, sometimes it costs around $2. I think this varies by state, but I’m not sure. Now you’re done with the weighing, but the fun math part still remains…
Using the results
If you’re towing a trailer, there’s more to calculate. The first weighing will tell you if you’re “legal” (within your GVWR), but to tow safely, you must also ensure the distribution of weight in the trailer isn't overloading any one axle. You get this by figuring out the trailer’s tongue weight. This tells you how much of the trailer's weight is being held up by your tow vehicle, and how much is supported by trailer's axles. Aside from avoiding overloaded tires and axles, this weight distribution has a big effect on how well the trailer handles on the highway. An overloaded rear axle on the tow vehicle will "lighten" the front wheels and reduce traction for steering and braking (P.S. that is BAD). In severe cases, you can lose front traction entirely under heavy braking. At the same time, having too little weight on the tow vehicle creates the potential for "tail wagging the dog" situations where the trailer "takes over" and your steering input is nearly ineffective for controlling the rig.
Here again, the printout from the scale is designed for semi trucks, not RVs, which makes this part confusing. So I’d like to share my spreadsheet as an example. (Yes, I'm an engineer, I make spreadsheets of everything. Witches have their cats; I have Excel.) This is a tool I made for my own use that I'm providing as a reference. Your calculations are ultimately your own responsibility. I hope it's helpful, but it's not an all-in-one calculator (it focuses on trailers). Plug in values in all the un-colored cells and check the results. At the bottom, a tongue weight percentage is calculated. You may also want to use the calculators provided on the site I referenced earlier (look near the top next to the yellow box). I made mine because it lines up a little better with the scale printouts.
For motorhomes towing cars or other trailers, I don't know enough about the various car-towing options out there to give robust advice. Most of the toad setups I've seen don't look like they would add any weight to the tow vehicle's rear axle, but I can't be certain. If this is you, please talk with your equipment and rig manufacturers to get a complete answer for how your toad impacts your weight capacities.
*One last caveat: Everything above assumes that the weight in your rig is perfectly balanced side-to-side. Commercial scales don't measure individual wheel weights, so they can't tell you if your rig actually is balanced. To get a truly complete picture, each wheel should be separately weighed. Then, all the same principles above can be applied. This kind of weighing is a lot less convenient and affordable than a truck scale, though. The SmartWeigh program, available to Escapees members, seems to do this at a good price (we aren't members so can't see for ourselves), but locations are very limited. There are likely other options available but you'd have to seek them out in your area. If you're not able to weigh each wheel it's still far, far better to go ahead and get a truck-scale weighing than to skip weighing entirely!
The Toaster Situation
The day the Toaster's rebuild was complete, we took it to the scales enroute to its temporary storage location. It weighed 7470lbs. empty (UVW). We re-weighed it before we hit the road, and it was 8140lbs., with 6500lbs. on the rear axles (rated at 3500lbs. each) and the remainder on the pin (20%). The truck's ratings were not being exceeded and everything looked good, but...we hadn't loaded any groceries yet and the freshwater tank was empty when we weighed it. Our 40 gallon tank would hold 320 lbs. of water, leaving 280lbs. for food, so we figured we'd be okay, and didn't weigh it again.
Over the next few months, we made modifications on the trailer, acquired a handful of belongings, and loaded up on food. Six months after our first weighing, we checked again and the Toaster had added a half ton to reach 9160lbs. Holy crap!!! Each axle was overloaded by 180lbs. -- and in fact, the rear axle was carrying more than that, due to a slight nose-up (as mentioned in my last post).
We needed to do something about this, but weren't ready yet. I knew the suspension was old and needed service, so I started looking into our options. In the meantime, we tried to avoid pressing our luck by adjusting how the trailer was loaded.
Options if you’re overweight
If you’re exceeding the GCVWR for your rig, there’s no fudging you can do about it — you must get rid of some contents to bring down your total weight.
But if it’s one of the other ratings you’re exceeding, you may be able to re-distribute your load. After we found the trailer axles were overloaded, we relocated dense, heavy items as far forward as possible to transfer weight onto the truck. Bulk food and canned goods went in a cupboard forward of the axles; dog food and bike equipment are in the front of the basement area. At the same time, fluffy sleeping bags and blankets were moved under the couch, which is directly over the rear axles. Most of the kitchen cupboards (at the rear of the trailer) are as sparsely-filled as we can stand. This shifted some weight onto the rear of our truck, reducing the overload on the axles (but it still wasn't enough). The truck, fortunately, had rear axle capacity to spare, so this was okay.
Things you can do to (temporarily) help with an over-weight situation, or at least reduce your exposure to an equipment failure:
- Redistribute wealth: Move very dense items (tools, workout equipment) away from the axle or vehicle that is overweight. This might mean an extra inconvenient step of moving things around before getting underway, or storing things in your toad or tow vehicle.
- Travel dry: Do your big highway miles with empty tanks, then fill up fresh water when you're close to your destination. This is more about risk reduction than elimination.
- Off-load possessions: Re-evaluate what you've got in your rig and take some stuff by a local Goodwill. We have actually been able to sell some things on eBay and Craigslist when in an area for a week or two.
- Cut rations: Okay, I don't mean to starve yourself, but maybe carry only a few days' worth of groceries instead of a week. Check that you aren't hauling around the same 5 cans of beans without ever eating them (something we are prone to). Especially look in the fridge -- beverages and condiments add up quickly. Or even consider traveling with an empty pantry, and buy groceries after setting up camp.
- Repackage: Especially in the kitchen, choose products in plastic containers vs. glass. Not only is this a lower risk for breakage, but it can save a lot of dead weight (and it can be really hard to find glass recycling on the road). Our spice selection used to be all-glass and that was a lot of useless weight. We've been gradually replacing them with plastic bottles. If you buy things in bulk, put a small quantity where you need it, and put the remainder in a better place for your weight issues. Dog food is a good candidate for this approach.
- Take it easy: Limit your highway speed to 55mph and avoid steep and poor-quality roads.
We’d love to hear your ideas about keeping weight down, fighting the tendency to gain more stuff, or packing ideas that let you control weight distribution better. Check back for my next post on this subject, which will cover our eventual solution to the Toaster's weight issues.