Keep your Offroad Rear Bar Connected?

Slawson Buggy 1

Photo Courtesy of BTR Wheels

Why does Hellwig only include quick disconnecting end links on our front offroad sway bars while the rear ones stay attached all the time?
First off, the reason people want to disconnect their sway bars in offroad conditions is because they believe the sway bar limits “flex”. Sway bars work by creating an additional spring to decrease the body roll. As the distance between the frame and the axle on one side increases more than the other, it has to twist the sway bar which acts as a torsional spring. This improves handling and stability on a paved road, but in an offroad condition (anything from rutted roads to rock crawling) you want to let the axle drop on one side more than the other to keep the body of the vehicle fairly flat and keep all four tires in contact with the ground.
With quick disconnecting end links, you can drive to trail (or commute to work) with the end links connected to give you a stable ride and then disconnect the end links in offroad conditions. This allows the driver to take the sway bar out of the equation and use the maximum amount of flex. We include these as an option for our Jeep Wrangler JK, Jeep Wrangler TJ, Jeep Cherokee XJ and Ford Early Bronco front sway bars since they see a lot of offroad use. For those vehicles listed, the front bars are made from 1-1/4” to 1-1/8” diameter chromoly solid material. This is very stiff and would prevent a lot of the flex. Additionally, they have fairly short arms which make the bars stiffer as well since there is less of a lever arm. This is necessary to control all the weight up front with the engine, drivers, etc. Also, for optimum on road handling characteristics you always want a greater roll stiffness in the front of the vehicle to prevent oversteer conditions.
Since the rear of the vehicle is lighter and needs less roll stiffness, the rear sway bars follow an entirely different design philosophy which allows them to stay attached and still work in offroad conditions. These bars are only 3/4” to 7/8” thick material with much longer arms and therefore have a softer rate. Additionally, they are tunable with 3 holes in the end to allow the driver to change the rate of the bar. We prefer to leave these attached offroad because, especially with a linked vehicle such as the Jeep Wranglers JK and TJ, it does help to have some roll stability even when offroad. These bars do not significantly decrease flex since they are softer and have longer arms so it is not worth it to remove them and leaving them attached does improve the ride stability in the sections between the rocks. Even professional Ultra4 offroad racers run a light rear sway bar which is engaged all the time. You can see Randy Slawson’s Bomber Chassis, the winner of this year’s King of the Hammers, in the picture below. This is about as extreme rock crawling as you can get but Randy still has a rear sway bar connected at all times.

 

 

Posted on Thursday, April 4th, 2013 in Tech Advice.
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