Setting your bars

[Motofreak]

How do you know when your stabilizer bars are set right? I have airbags as well. 10k trailer when loaded.

 

[gonzo2]

Well. I'm going to assume you are asking about the spring bars for a weight distributing hitch.



Assuming again that you have the hitch height correct (trailer level or slightly tounge heavy), The easiest way to check is by using a tape measure on the front and rear bumper of your truck. You need to check the heights without the trailer, with the trailer and with the trailer and bars.

The idea is to use the height differences to tell when you have transferred enough weight to the front axle such that the front bumper does not rise from the empty height before trailer hook up. This should allow you to get a good indication of how good your set up is working.



The other way is to go to a scale and use axle weights to get the same information.



As a side note, 10K trailer usually means you need at least 1200lb bars. I've never towed toy boxes but you may find that load placement in the back has an impact on your handling characteristics.



If you are setting up from scratch there is some excellent info here:

RV Towing Tips



Cheers



Craig

 

[DIESELMAN]

You mean the right way? Here's my way, and it works well.



The bars should really only need be set up once. You need to adjust the length of the chains as recommended, usually 4 - 6 links. Too short and it will bind and either bend something during turns or slip the brackets on the tounge. Too long and they will be doing nothing, the bars could actually fall out pulling onto the highway over the sidewalk.



Start by setting the hitch height. back the truck up to the level trailer, make sure the trailer is level front to back. Adjust the Yoke height so that the ball and hitch are at the same level, after allowing for the truck to settle to a level stance too. Do this without hitching up yet.



Now adjust the bars by adjusting the head angle.



To aid in adjusting, use the tounge jack to lift the weight off the hitch between adjustments.



Let ALL the air out of your airbags. Now lower the weight of the trailer onto the hitch, hook the spring bars, and measure the truck front and rear wheel wells. Install the bars and measure again. What you are looking for is that the truck returns or settles nearly to level, and is still lower than the rear end empty height was, NEVER THE SAME AS EMPTY OR HIGHER ALWAYS LOWER.



If the rear lifts to high or sits too low, you need to adjust the head angle of the hitch ball. Be sure to use the spacer washers that come with most hitches for the slack pin, you can't tighten thehead tight enough without those washers and the adjustment will be lost. Tip the hitch ball forward to lower the pressure, and the truck rear, and tip it back to increase bar pressure, and raise the truck rear.



Make sure you use the jack to take the weight off the hitch before adjusting the hitch!



Small changes really make a large difference, the angle will be within a couple of degrees of vertical. What you are changing is the angle of the bars exiting the bottom of the yoke. Since they are chained at the tounge, tipping it back imparts more longitudinal stress, and transfers weight away from the connection point, the ball, and causes it to rise, tipping forward reduces the stress, and lowers the ball. Think about this and you will understand how it works and why it is adjusted this way.



If you have this pretty close, the truck and trailer will now be perfectly level with each other, and the loads will be evenly distributed across all axles. It will track like a dream and you won't need a friction sway device, ever. Although Cam-Bars help with stability by increasing preload whenever the trailer and truck are not straight with each other.



Now you can add air to the airbags until the rear of the truck just starts to rise and no more. If you add payload to the truck, increase air to return to level, and always load the trailer evenly maintaining 10-15% tounge weight. Never use air to raise the rear above the level you set as it will loosen the bars and they could dislodge.



Remember, bars must be sized to the tounge weight for this to work, 750 bars on a 1200 lb trailer tounge weight will never level out correctly, the head will not be level, and the chains will be too short.



Hope this helps.

 

[Motofreak]

Thanks Dieselman, sounds like good advice, will try it this weekend.

 

[apkole]

Dieselman,



Thanks for the great instructions! The truck is the '01 in my profile, the RV is a 98 Sierra 26' with a slide. The RV dry ship weight is 6200 lb. The dry tongue weight is 615 lbs. The WD bars are rated at 750 lbs. (Hmmm, bet those are just a little light for the RV loaded ) New heavier load range tires were installed last fall, as the OEM tires were failing.



I've been frustrated for quite some time with the way my rig handles. I'm in the process of setting up the towing on the new(est) truck. I worked for three hours yesterday afternoon attempting to get the adjustments set right. (Tow 5 miles, adjust, tow 5 miles, adjust . . . . ) Can't seem to get the yaw and sway out of the truck, although the trailer seems to be ok.



New Rancho 9000 shocks were installed last week. They are set to the stiffest adjustment. New Michelin LTX tires were installed about 2000 miles ago. Rear tire pressure is set at 75 lbs, front at 70 lbs. The RV tires are set at the 65 lb max as noted on the tire.



Because of the height of the hitch on the '01 truck, the drop on the hitch is about 6". At this ball height, and with two chain links dropped on the WD bars, the RV measures the same height to the frame at the axle equalizer, the front and the rear. (18 1/2" from frame to ground. ) With this long of a drop, is it possible that sidways motion of the trailer tongue is exerting some torque on the horizontal portion of the insert, causing some unloading of the rear suspension one one side or the other?



The rig feels pretty solid up to about 60 mph. At 65, it feels on the edge of the control envelope. A full size pickup or van passing gives a distinct buffeting effect.



At my hitch installers recommendation, I took reference measurements front and rear of the truck at the wheel wells (center to ground). After adjusting the WD bars, the truck sets at same height as before hitching up.



Your instructions seem to indicate that either a) there is not enought weight on the rear axle and/or b) the angle of the ball is not correct. (It does have an angle from vertical. ) Will a single notch adjustement dramatically change the handling of the rig?



With the extended cab and the topper (on a short box) I know that the rig presents more area to a cross wind than the '99 (std cab ,long box - no topper) did.



Any one have any suggestions? We are going to try to head to Destin, FL this spring for a break from the Michigan cold, cloudy weather. I would rather it not be a white knuckle experience.



One thing I haven't checked yet are the RV wheels, or the amount of play in the bearings. I did re-pac the bearings a couple of years ago. This RV hasn't had many miles on it since the bearing service.