Reese has a chart that shows the recommended bar ratings versus hitch weights. It can be found at the bottom of this
product catalogue. In the case of Reese bar ratings, "hitch weight" also includes the tow vehicle cargo weight. This chart is hard to find and does not show up on a google search - the only place it is AFAIK is in the pdf product catalogue. I *think* Reese did not include the cargo weight in the past and this is a more recent change.
As an example, say your truck has 400 lbs of passengers, groceries and camping gear and you had 800 lbs of TW fully loaded, the spring bar should be rated at 1200 lbs. If your cargo was 600 lbs, you'd need their 1500 or 1700 bars depending on if you had round or trunnion style bars. Or another way of looking at it is if you had 1200 lb bars and 800 lbs TW, you'd limit your cargo weight to 400 lbs. I suspect that Reese owners would tend to undersize their bars without referencing the chart.
AFAIK, upgrading to 1500 1700 lb bars requires a stronger Reese hitch head. As well, you probably need a new receiver. They do not list a 1,000 lb bar in round or trunnion style.
Undersized bars can result in a lot of bounce in the rear of a TT and also not being able to transfer enough weight back onto the steer axle. Oversizing bars can cause damage to to the A-frame. Not sure at what bar ratings this can be an issue. I believe in the case of BAL/Norco Ultraframes, they specify a max. bar rating so as not to damage the frame. If you look at the welds on your TT between the A-frame and I-beams, it makes you wonder why more A-frames don't separate from the main frame. We had a frame shop look at a previous TT and the owner was shocked at how poor the welding of the A-frame to I-beams was. If upgrading to 1500 or 1700 lb bars, perhaps it would be a good idea to have a certified welder upgrade the welding and add some re-enforcement.
Our TW is about 950 lbs, up from the 540 lbs factory dry hitch weight. With the 800 lb bars we initially bought I could not get enough weight back onto the steer axle and there was a LOT bounce in the rear of the TT. Bought 1200 lb bars and that cured the weight transfer and susbstantially reduced the bounce. We are on the borderline of needing 1700 lb bars according to Reese's chart depending on what and who we have in the truck. Don't want to have to spend the money on an upgraded receiver, hitch head and bars and the 1200 seems pretty good as is. I love our dual cam hitch and the way it's pro-active and makes the truck and trailer want to snap back into a straight line. A friction only based WDH requires some driver input to keep it straight. I drove a friend's TT last year and did not like the feel of their setup with friction sway bars.
We have an F250 and 29' 7K lb TT and I drove the season before last without the dual cam installed and it was not a good towing experience at all. Installed the dual cam arms/brackets last year and had them all season. HUGE improvement in sway control and handling. Now I can easily drive down the interstate with a tractor trailer on each side at 65 mph and the curviest of roads are no problem.
