TOWCHECK FIELD GUIDE
What a towing calculator cannot tell you
A calculator can organize arithmetic and compare entered ratings with estimates or measurements. It cannot inspect installation, tires, brakes or structure; predict handling; verify laws; or certify a combination.
What the terms mean
Results inherit every input error and assumption. A green margin represents arithmetic against an entered value, not an approval. Unknown data should remain unknown rather than being silently replaced with optimistic defaults.
Worked example
Common mistakes
- Treating an estimate as permission
- Entering zero for an unknown rating
- Using an old result after loading changes
Frequently asked questions
Does TowCheck say a setup is safe?
No.
Why show formulas?
Visible formulas make assumptions auditable and easier to verify independently.
What should I verify outside the calculator?
Labels, manuals, component documentation, installation, actual weights, equipment condition and current applicable rules.
Primary references
These sources support terminology and general planning context. Use the current documentation for your exact vehicle, trailer and components.
- Ford RV & Trailer Towing Guide
- NHTSA interpretation: GVWR and GAWR definitions
- NHTSA FMVSS 110 tire-selection test procedure
Continue with your own numbers
Run the Complete Tow Check, use the scale worksheet, or review the calculation methodology.