d1h wrote:
Recently bought a Chevy truck with the built in brake control. My question is what is the best setting for the gain? I'm towing a 27ft TT.
No one can answer the question except you.
There are too many variables involved to make it a universal, one answer fits all terrain, all weights, all lengths, all type of loads hauled.
Answering your type of question is also like trying to provide an answer when someone asks "my fuel gauge reads 1/2 tank, how much longer can I drive?"
Start towing. Adjust it until it gives adequate braking for your trailer.
But don't start driving and jam on the brakes so the trailer brakes lock up. That will flat spot your tires. I always start with the setting somewhat low and dial up as needed when I get a new tow vehicle or new trailer.