Traveling Payload

[Bdub&Ax]

First post here — I'm Brent, engineer out of Ramona, CA. Been overlanding about 20 years, currently in the market for a Grenadier. While I'm between rigs I've had time to dig into something that's been nagging at me for a while.


Genuine question for this group: do you know your actual payload number right now, with your rig loaded for a trip?


Not the sticker. Your number — with the tent, the batteries, the water, the recovery gear, the food, the people.


Most of us don't. I didn't. I started doing the math after a sketchy moment on a shelf road and realized I had no idea how top-heavy my setup actually was.


I ended up building a tool to work it out properly — payload vs. GVWR, center of gravity height, rollover threshold, tire pressure under real load. I want to put it through its paces on more vehicles before I release it.


Looking for 15–20 people willing to run it and tell me where it breaks. Free, works offline, no account required.


Anyone want to actually check their numbers?

 

[pnwlife]

Interesting. I know my vehicle's numbers and have made modifications to allow it to handle those numbers. Getting one's gross weight is cheap and easy at any CAT scale; coming up with COG height and rollover threshold seems a lot less so. How does your tool come up with those figures?

 

[Bdub&Ax]

Interesting. I know my vehicle's numbers and have made modifications to allow it to handle those numbers. Getting one's gross weight is cheap and easy at any CAT scale; coming up with COG height and rollover threshold seems a lot less so. How does your tool come up with those figures?

Fair question — It doesn't measure COG. It models it.


The database has OEM track width and unladen CG height for each vehicle — pulled from NHTSA data and manufacturer specs. You enter your gear with weights and where it's actually sitting: roof, bed, interior. The tool does a weighted average on the full loaded system and spits out a CG height from there.


SSF is T ÷ (2H) — same formula NHTSA uses for the rollover star ratings.


It's a model, not a tilt table. But if you've already got your CAT scale numbers and you know your mods, plug your real numbers in and you'll see exactly what all that weight up top is doing to your stability factor.


Happy to send you a free Pro license if you want to run it against your actual build.


— Brent

 

[pnwlife]

Fair question — It doesn't measure COG. It models it.


The database has OEM track width and unladen CG height for each vehicle — pulled from NHTSA data and manufacturer specs. You enter your gear with weights and where it's actually sitting: roof, bed, interior. The tool does a weighted average on the full loaded system and spits out a CG height from there.


SSF is T ÷ (2H) — same formula NHTSA uses for the rollover star ratings.


It's a model, not a tilt table. But if you've already got your CAT scale numbers and you know your mods, plug your real numbers in and you'll see exactly what all that weight up top is doing to your stability factor.


Happy to send you a free Pro license if you want to run it against your actual build.


— Brent

Sounds promising, and an opportunity to test it out would be great!

 

[Bdub&Ax]

Rig-Locker Pro Beta

Rig-Locker Pro is the full system I built for overlanders who treat their rig like the serious piece of equipment it is. Lite answers "will my loaded rig make it home safely?" Pro answers that and "is my whole build dialed — power, gear, weight, and logistics — before I ever turn the key?" It...

riglocker.gumroad.com

 

[Antique Overlander]

No idea & with a 4.5" lift, being top-heavy is one of several reasons I won't RTT. Besides having a dog, wife & in my 60's
That said, I'm curious about weight. It's 1 reason I'm building a gear trailer.
I will def need to know once I start doing longer trips!