How Does Curt RVi 4 Supplemental Brake For Flat Towing Know When To Apply Toed Brakes?

Updated 09/03/2025 | Published 08/07/2025

Question:

How does the Curt RVi4 know when to apply the brakes? My older one years ago when I used it would act up sometimes and not work when needed.

asked by: Denise

Expert Reply:

The RVi4 Portable Supplemental Braking System from Curt # RVI44FR uses an onboard accelerometer to detect changes in inertia, so when your motorhome slows down, the RVi4 senses it and applies the toad’s brakes proportionally. It even adjusts for uphill and downhill slopes, so it’s not more sensitive going downhill like some older systems. Pretty smart braking tech in a simple setup.

What system have you used in the past?

expert reply by: Andrew N

rvi 4 how it works
(click to enlarge)

Denise

9/3/2025

That’s a lot better than the old box I had, Andrew. Does the RVi4 still need to be calibrated every time I set it up?

Andrew N.

9/3/2025

@Denise Good question, Denise. The RVi4 only needs a quick calibration the first time you set it up in your vehicle. After that, it remembers its position, so you don’t have to redo it every trip. Just place it, power it on, and you’re ready to tow. Are you planning to move the RVi4 between multiple toads, or will it stay in one vehicle?