Saturday, September 23, 2023


Nifty device tells you if your RV is dangerously overweight

By Tony Barthel
The CURT BetterWeigh™ is a device that helps vehicle owners determine tow weight, cargo weight and other factors in their vehicle’s towing through the use of the OBD II system and a smartphone app via Bluetooth. 

CURT, a manufacturer of hitches of all sorts as well as other components, sent me a BetterWeigh device to test out. CURT is a member of the Lippert Family – you probably recognize that name as they are a manufacturer of all sorts of RV components. 

So what is it?

Curt Better Weigh digital scale review
The CURT Better Weigh screen on my iPhone

The Curt BetterWeigh™ is a device that hooks to your vehicle’s OBD II port and reads a combination of factors to deliver readings on vehicle weight, tongue weight, pin weight, payload and weight distribution. 

It appears to use sensors in the device itself to measure the vehicle’s angle (how much the springs deflect when you hook up your trailer) and combines that with information from the vehicle’s computer to achieve other measurements. All of this is delivered via Bluetooth to your smartphone or tablet via a proprietary app. 

The CURT BetterWeigh uses what the company calls “TowSense™” technology. From the manufacturer: “TowSense technology is a digital towing scale system. Using an accelerometer circuit, TowSense measures changes in the velocity and pitch of your vehicle. It uses this data to calculate weights associated with towing and hauling.

“The BetterWeigh tongue weight scale wirelessly connects to your Apple or Android phone to display the weight of the vehicle, trailer, cargo/payload, tongue weight, pin weight, weight distribution and trailer brake gain.”

Setting it up

I plugged the CURT BetterWeigh™ into my 2015 Ram 1500’s OBD II port and went through the setup. This means telling the system what kind of vehicle I have and, by inputting the serial number, it knows the year, make and model along with which engine, transmission and gear ratios are on the truck. 

From there, you drive the vehicle on a straight, flat road several times to get the calibration. This determines how much accelerator pedal input is used to achieve certain vehicle speeds so you have a benchmark. 

The setup process is pretty specific but is necessary so the BetterWeigh system establishes a benchmark for your vehicle and then whatever you’re towing or have as cargo in the bed. 

Does the CURT BetterWeigh work?

After calibrating the BetterWeigh with an empty truck, I added my travel trailer, a 2017 Rockwood Mini Lite 1905s – a relatively small and light trailer. The BetterWeigh estimated that I had over 550 lbs. of weight on the tongue of that thing. Considering that the trailer’s dry weight is about 2800 lbs. and it was full of water and supplies for a week’s worth of camping at the beach, I believe it was fairly accurate. 

The calibration phase also has an idea of what the truck weighs unloaded, so I gave it a test to see what it thought my trailer weighed. It was closer to 4,200 lbs. Let’s see – cast iron cookware, a week’s worth of beer, winter clothing and blankets and 30 gallons of water. I believe it was pretty close to accurate, considering this was like lying to yourself that the holidays didn’t pack on many pounds even though that lousy scale reads otherwise. In other words, I would have guessed that the trailer was lighter than this but, in actuality, it wasn’t. While I didn’t drag it to a CAT scale to verify the numbers, I don’t have reason to think it was tremendously inaccurate. 

I also ran the tests on the way home and the tongue weight did drop (no more fresh water but a full tank of black water, which is in the back of my trailer). Furthermore, it estimated that the trailer was about 3,800 lbs. which, again, seems accurate. I drank all the beer. 

Is the CURT BetterWeigh worth it?

I’ve seen a few reviews of this device online and some folks are really happy with it, others not. It seems the difference may be in the vehicle itself. The Ram pickup line seems to work very well with this, but I can’t speak to the other brands of vehicles. 

I think this is a decent way to get some idea of what’s going on with your weights, but still no substitution for a CAT scale or equivalent. From my own experience, I think the numbers it provides are reasonably accurate but certainly not certified, as you’d get from a true scale. 

According to Steve Kass from RV WeighSM, who has weighed hundreds of RVs at FMCA rallies and other events, the number of RVs that are overweight is significant. Honestly, it’s wise to have some idea of what you’re towing back there and how close you are to the capacity of your tow vehicle. 

Considering how easy this device is to use and how handy it is, for $99 on Amazon it seems well worth it, especially for anyone who might be even moderately close to the maximum towing capability of their vehicle. 

What is OBD II?

As part of the overwhelming regulation in the auto industry, all vehicles sold in 1996 and beyond need to have an On-Board Diagnostics (OBD) port. This is a second-generation system so is labeled OBD II. 

Essentially this gives anyone access to much of the technological functionality going on in the vehicle computer systems. Using a standardized connector, the idea was that technicians can read what’s going on internally, which helps them diagnose vehicles as they become ever more computerized. 

Today, a modern vehicle uses computer technology to manage the engine, transmission and often much more. Emissions sensors, oxygen sensors and so much more are the key to why our vehicles have more power and are more efficient at burning fuel when all systems are go. Yaw sensors, sway sensors, braking input, throttle input and other digital babysitters are the key to why cars are safer today. Basically, technology can replace a lot of the knowledge we used to have to keep our vehicles on the straight and narrow. 

In fact, my own truck utilizes some of these vehicle dynamic sensors to help eliminate trailer sway by applying braking to the trailer if it senses sway. This is what a smart driver would do but, let’s face it, we’ve all seen others who aren’t smart drivers. 

Any complex technological system can also fail, and does, especially when combined with the tremendous heat and unforgiving realities under the hood of a vehicle. 

What I do with my truck’s OBD II

Furthermore, idiots like me can access the various functions in their vehicles and actually modify or hack them. My own Ram pickup has all sorts of computer subsystems for the body (lighting controllers, etc.), emissions, and more. The list of computers that appears when I get into the OBD II system is incredible. 

These systems allow the Ram to shut off four of its eight cylinders to improve fuel economy when cruising. But the level of computerization and sophistication can also be an issue when something goes haywire. 

So when these systems go haywire, the OBD II system was designed to allow a technician to peek into what’s going on and use the system’s reporting to make a change in less time. 

Or, just modify the heck out of your truck’s electronics and then wonder why it runs funny. 

You can find the CURT BetterWeigh on Amazon.


Tony Barthel has been a life-long RV enthusiast and travels part-time with his wife where they also produce a podcast, write about RVs and love the RV lifestyle.


  1. I’m very skeptical of the OBD port and sensors being able to do better than a ROUGH estimation of weights, and rough isn’t good enough here.

    I am however much more curious of what “hacking” methods were used and results Tony is getting in totally unrelated areas… I’d really like to know the secret command to get 40mpg and become radar-invisible, if he can post that code sequence… 😉

    –Fellow Embedded Systems Hacker

  2. Look at the tests on the Fit RV video channel. He does two, original test, then again after factory engineers helped him. Be very careful if you use this device, depending on your particular rig you may, or may not, get an accurate weight.

    • Excellent point. I’m disturbed by Tony’s review. “I hooked it up and it seemed about right to me” is not a review. He should have taken it to a CAT scale, that would have been useful information.

      • This is very valid point. Unfortunately I live in a very rural area and, with Covid and such, there isn’t a Cat scale within 200 miles of here at the moment. That’s why I’m very clear that you won’t have accurate numbers without the Cat scale but this can give you some idea.

        Also, I know others such as James from The Fit RV who have had much worse results than I have which makes me believe this is better with some vehicles than with others.

        I think it’s obvious based on my conclusion that this is only an approximation and not accurate with all vehicles. So I stand by my point – especially if you read the whole story and not just the opening paragraph.


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