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October 2012 Nuts & Bolts Tech Questions

Dodge Ram With Tube Bumper
Fred Williams
| Brand Manager, Petersen’s 4Wheel & Off Road
Posted October 1, 2012

Shocks, Bumpers, And More!

Prerunner Protection
Q I have an ’01 Dodge Ram 1500 Sport, and I’ve looked everywhere to find a prerunner-style bumper for it. I want to make her look as cool as the new RamRunner package that Mopar is offering. My question comes out of concern for my radiator. Is it possible to find a prerunner bumper without sacrificing the safety of your daily driver? Will they protect my truck from minor bumps from light poles or the idiot doing burnouts in the parking lot of school? (I ask because I’m 16 and you know us teenage drivers). I love my truck, as it was a summer break project with my dad (bought it after it had minor crash). We put on new fenders, headlights, radiator, and a whole new front axle and hubs, so I want to keep her safe while having good looks.

A Check out Addictive Desert Designs (ADD), The company has a prerunner bumper for your truck. I feel a prerunner front bumper will protect your truck just as well if not better than a factory bumper. Most factory bumpers are not really that heavy-duty, and a prerunner bumper like the ADD one is frame-mounted and built of tubing and a stout skidplate. I think it will be fine for daily use and off road abuse. Of course, any major collision can damage any type of bumper, so this must be taken within reason, but I see no reason why it won’t help protect your truck and make it look better.

Sway Bumps?
Q I am building a ’91 YJ. It has 42-inch Irocks and 1-ton axles. It is four-linked front and back with 14-inch Fox air shocks in the rear and 14-inch Radflo air shocks up front. What would be better: air bumps front and rear, or a sway bar like Currie’s Antirock? I see some with just air bumps and some with just the sway bar. I’m still in the mockup stage of the build and don’t know which one to go with. It will be strictly off-road. Any input would be greatly appreciated.

A Air bumps (also known as nitrogen-charged bumpstops) and sway bars do very different things. This is like asking if you should add a winch or a trailer hitch; both are useful, but they don’t do the same thing at all.

A sway bar is a torsion bar spring that is linked to the axles and the frame. Its sole purpose is to stabilize the vehicle against sway or body roll. As your suspension cycles up and down the sway bar moves freely, but as your suspension articulates (one tire moves up and the one on the other side of the axle moves down) the sway bar twists. This is a spring-loaded twist, and it will try and resist this articulation. The sway bar works throughout the suspension travel, constantly trying to keep the vehicle level over the axles for a more stable driving experience and even tire-to-ground pressure.

Some suspension designs are less prone to body roll than others, and some may not even need a sway bar. This is hard to determine without seeing your suspension work. It may be best to finish the vehicle without a sway bar, but leave room for it should you wish to add one later if you have significant body roll. The Currie Antirock Sway Bar is great for both on- and off-road use, and Currie has an informative video on its website about how they work:

Air bumps are designed to help control the compression damping of your suspension. They are often 2 or 4 inches long, and as the suspension compresses they hit the axle and slow down the last few inches of suspension travel. Inside the air bump is a small amount of oil and a nitrogen charge. As the suspension compresses and the axle begins to compress the air bump, the resistance ramps up very quickly to slow and stop the suspension movement. Consider air bumps a worst-case-scenario rescue that protects other components from crashing together if you take a big hit and compress the suspension fully.

Your air shocks are very similar to air bumps. In air shocks the nitrogen charge and large-diameter shock shaft work together and act like the shock and spring. It can also ramp up resistance in the last few inches of travel and acts similar to an air bump.

In your case with air shocks I would recommend the sway bar over the air bumps. Your air shocks can be tuned to act similar to air bumps in the final inches of compression. However, they are less likely to fight body roll or sway. If you were running a coil or coilover-shock type of suspension the air bumps would be more helpful, but you may still need a sway bar. I think in your case a sway bar is the smarter upgrade at this point.

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