Sway problems

BenK wrote:
As for tire pressure...rim width plays too

Also sidewall aspect ratio

Majority of folks today are opting for higher unsprung weight (metal weighs more than air and rubber) via lower profile & larger dia wheels and that is a good thing for towing....but...8f the rim width is on the narrow end of the tire OEM's recommended range, the the added sidewall bendback negates increased handling ability if lower profile sidewalls

#1 is higher slip angle...a ride quality component to tire performance. A wider rim reduces slip angle to allow more precise steering wheel response.

A narrow rim width has more sidewall bendback, so the tread squirm is increased... while the sidewall's increased "wave" has the wheel pointing one way and the tread points on another track. This also allows more wallowing as they try to realign

Why my rims are 10 inches wide. Sure it rides like a truck (of which it is to me), but steering precision is tops and next to none, and no ride quality (of which I don't care for)

Your lower trailer tire PSI will affect, as there will be a bit more sidewall flexing....that will allow the trailer to both lean more and wallow more as the rim rolls back and forth trying to center themselves on the tread track

IMHO...use the chalk method to check tire pressure vs loading. I also check them often and also look for where the outer tread rib's pavement wear edge is. If it is inward of the tire edge...PSI is to high for your load & driving style...if it is on the sidewall side of the edge...PSI is not high enough for your load & driving style

Please report back on how it goes