got a question for people who tow alot.towing my tt home for the winter the dang thing swayed at speeds over 55 mph.it did not do it this spring when i took it down to our river lot.i am thinking maybe i took to much weight off the rear of the truck with my wd. bars.that would be the only thing that might have changed.i had the same stuff in the trailer as before.the reason i say the bars is my brother in law tightened them up i did'nt this time.i usally only use them to help take the bounce out of these backroads.my tt only puts the rear down at most 3 inches without the bars.i have a 99 f-250 5.4 and a 28ft. tt about 8,000 with everything in it.
thanks for any help or ideas.much appreciated

 

or a low tire?

Sam

 

checked all tires.camper at 50lbs.like stated on tire and 80 on truck as called for. i always ched them because i have a river lot and unless it floods i keep it there all summer

 

I'd weight the axles with the trailer and see what you have. You may have taken too much weight off of the rear axle.

Also, I doubt you really need a full 80 PSI on each tire. 80 PSI is the pressure required to carry the maximum weight listed on the tire. Too much air will cause the tire to balloon and ride on just the center of the tire. It won't handle well.

 

The shifting weight issue is an interesting one. I'll share my towing this morning. I had to tow two of my trailers to the local repo auction from the lot down the interstate. The first trailer was 36 feet and had a GW of 10,000 pounds and likely weighed about 8,000 pounds. It was way heavy on the front and the tail of my 350 dropped almost 3". Ran very well all the way to the auction site. Nary a sway, no matter what passed me.

Next up was a 38-footer, 10,500 GW, which was so light on the tongue that it dropped the tail of my truck not a bit. couldn't even tell it was on the back in terms of change in bed height. Truck at standard height, trailer perfectly level. So I'm towing. Bed of truck bounces like it is empty. Trailer actually tries to sway a bit when semis go past. Dually is never bad, but this was the worse tow I have had in a while.

Long way to say, weight on the back really does make a difference, although it goes without saying there are a multitude of factors that can affect sway.

So adjust the bars to load the bed a bit more and take it for a spin would be my advice. Sometimes it doesn't take much to make a heck of a difference.

Glad to hear you are routinely checking tire pressures!

Good luck,

Steve

 

thanks for the help.i will try to let more weight on the truck axle and see if that helps.if i dont run 80 lbs. on the truck wont that increase tire wear and affect fuel economy?

 

It might effect fuel economy, but no on the tire wear. If anything, running too much air will wear the center of the tires prematurely. You basically want the amount of air in the tire that causes weight to be applied equally across the face of the tire. If you have too much air, the tire balloons and rides just on the center, wearing the center out early. Too little air and the sidewall flexes out, causing the center to lift, putting all the weight on the outside of the tire, wearing the outsides prematurely. Too little air also causes too much sidewall flex with generates heat and can cause the tire to fail prematurely.

 

what pressure would you reccomend? maybe 60 or 65?

 

It depends a lot on how much load you have on the truck.

Empty, I run 60 front and rear. My door sticker says to run 55 in the front and 75 in the rear. I'm making an assumption that the door tag has me putting enough air in the tires to properly carry the maximum load allowed for each axle. 55 seems to low for me, so I go with 60. On the rear axle, when empty, there is LESS weight than on the front axle, so 60 should be good enough for the rear also.

Now when I put a load in, pressure obviously go up. This is where I think you need a scale to know how much weight your putting on the axle. If you're putting gross axle weight rating (GAWR) on an axle, then you need all the pressure the door sticker says for that axle. If you're half way between empty weight and GAWR, then maybe you need air about halfway between your normal 60 and whatever the sticker says.

There is an exact science to it. Unfortunately it can be hard to find. There should exist load tables for every tire out there. I have one that I use that is for a pretty common load range E tire in my size. It tells me, given X weight on the tire you should have Y pressure.

Another way, if you're really ****, (like me) is the temperature method. I have an I/R thermometer. Your goal is to have an equal amount of weight across the surface of the tire. If you have too much weight, your going to be riding on the center of the tire and the center is going to be hotter (after driving for awhile) than the outside edges. If you don't have enough air, you're going to be riding on the outside edges and they will be hotter than the inside. I go for awhile and check temps. If it's even, I'm OK. I also tend to over inflate at first, because I can always let some air out but it can be hard to get air to put in sometimes.

The only time I ever ran the full 80 PSI front and rear is when I was carrying a slide-in camper. I didn't need the pressure for the weight of the camper, but because of the very high center of gravity, having full pressure helped control a lot of sway.

To give a simple answer. I run 60 all the way around when empty. When moderately loaded (around 1-2k in the bed, or pin or tongue), I run up to 65 on the front and maybe 70 in the rear. If I'm heavily loaded (2 to 2.5k) I'll go up to 70 front and 75 back.

If I'm really overloaded (I've had as much as 4k in the bed, but usually about 3k), I'll do 70 in the front and 80 in the back. And like I said, with the camper, 80 all the way around.

Now aren't you glad you asked?

 

I run 80 all the way around all the time. I usually am doing something and find it a PITA to air up and then air down.

 

Trailer sway is caused by many things, not just how the vehicle is loaded. Obviously the heavier things are, the less they sway, but things like tire condition, tire pressures, wind conditions, etc. are all factors. Wind and length I have found are THE most prevalent factors. A short box truck will not handle sway as well as a long box truck. A longer trailer will be much more likely to sway than a short one. The tightness of your sway control (and its presence) will determine alot about your sway.

I have to say that, regardless of the amount of weight distribution, I have never had that really affect the amount of sway my vehicle has when towing.

 

thanks for the help again.i will try leaving more weight on the axle of the truck and see if that helps.i do have a new sway control kit i just never installed it yet.i only tow the camper abot twice a year but its a pain only goin 55 or so.the tire pressure vs. the load i will have to try and adjust.right now i have 65 all the way around but planning on hauling coal this week (1500 or 2,000lbs.) but that depends on how the baby makes out at hershey pediatrics.well thanks again for all the help