Suspension Air Bags vs Overload Springs

by Jarred Potter on January 10, 2013

Getting ready to tow a trailer or pull a heavy load?  Load support products help increase your trucks level load capacity as well as controlling heavier loads. We are going to compare two popular solution of load support and which one works best for you.

 Air bags:                                

  • Easy install
  • Bolt on designs
  • Many popular kits offer no drilling
  • Simple air adjustment for changes in weight
  • Offers up to 5000 lbs. of weight leveling ability
  • Vehicle can return to factory ride at the push of a button
  • Custom fit
  • Limited lifetime warranty
  • Require monitoring air pressure to avoid damage to air bags         

Overload springs:

  • Easy install
  • Bolt on designs
  • No drilling required
  • Progressive designs for no adjustment needed
  • Offers up to 5000 lbs.
  • Most install in less than one hour
  • No worry about leaks
  • No restrictions off road
  • Due to preloads, for quite no rattle performance, they can make for a firmer  ride
  • Often more noisy

    

Suspension Air bags:

          Air Bags for suspension have been in use on vehicle for many years. They are used on commercial vehicle to obtain high rates of load capacity. The bags for the trucks and SUV’s work similar to the ones for big rigs. They work in conjunction with the factory leaf spring to provide more load leveling capacity. They attach to the frame and run down either to the axle or the top of the leaf spring. When air is added to the bags they will resist the frame dropping when the load is placed on the rear end of the vehicle.  The air bags use different air pressures to change the load range of the bags.  As a general rule, the air helper springs will support approximately 40 lbs. of load for each psi of inflation pressure (per pair).  For example, 50 psi of inflation pressure will support a load of 2000 lbs. per pair of air helper springs.

For most of the more popular applications, air bags are a no drill bolt in to factory holes installation. This makes installing these kits fairly easy. The hardest part is running the lines and making sure they are tucked up out of the way and fastened to the frame to stay safe. You will want to route the lines in a way that they stay clear of heat from the exhaust and that will ensure they will not be pinched or kinked obscuring the airway. The lines can either be ran to a compressor or out to a Schrader valve (the same style air valve used on your vehicles tire), for filling the bags.

All double convoluted style bags boast a 5000 lb. load rating. These are found on most of the larger pick-ups and SUV’s.

 

The tapered air sleeve and straight sleeve will offer a slightly lower rating around 2000-3000 lbs. per pair. These bags will be found on a lot on the half ton and downsized trucks and SUV’s.

 

Coil bags are offered for most any vehicle, front or rear, with coil spring suspension. These bags install in the center of the coils offering around 1000 lbs. load support.

  

                 Air bags take a little more maintenance than overloads. Air pressure has to be monitored to maintain the minimum 5 psi required in the bags. If the 5 psi is not maintained while the truck is in motion damage could occur to the bags. There are compressor options that monitor it for you and maintain it for you making them less hassle. Air bags are subject to leaks and constant monitoring of the air pressure but you can beat the ride quality and adjustability of an air spring. If you are looking for extra support with the option to be able to return back to a factory ride and don’t mind a little preventative maintenance, the air bag is the right fit for you.  At suspension connection we offer air bags from popular manufactures like Firestone, Air Lift and Hellwig.

Overload springs:

The over load spring is a little more indestructible design over the air bags. This application works well on trucks off road that are subject to rough terrain. Going thought brush will not have you worrying whether a stick will come up and damage the overloads. This style also is not attached to the frame of the vehicle limiting wheel travel. This style of overload is more of a set it and forget it design. Once it is installed most people leave them alone, mostly due to the difficulty of having to crawl under the vehicle to adjust them. Adjusting them requires wrenches to tighten the bolts holding the end u bolts in place. There are some styles like super springs that work with a shackle and roller making the more of an automatic progressive style. As the spring flattens out the roller repositions itself to offer more support to the factory spring. Overloads work progressively. The more the spring flattens out with load the more weight transfers up to the overload. They are designed like that to try to optimize the best ride quality when not loaded, but because there is some tension required to eliminate rattles and noise, this will affect the ride some.

 

Styles like Hellwig progressive overloads use a u bolt on the end for adjustment. The tighter the u bolt the quicker it engages to keep the vehicle from squatting down as much before the transfer.

 

Hellwig also offers their pro series line. This line utilizes a unique polyurethane block that applies tension to the u bolts to not only allow you to leave the u bolts looser on the ends for a better ride quality but keeps them from rattling  making for a quieter ride.

 

 

Super springs offer a unique patented self-adjusting suspension stabilizing system. This system works with a shackle and roller resting on the factory spring at the ends. As the spring flattens out the roller reposition itself to the point of least resistance. The shackle design has two positions a lower and higher to allow for more adjustment. The lower position hole offers a better ride quality than the upper hole. Super spring claims that this style of adjuster automatically activates as needed and the anti-sway feature reduces body roll by 30%

Overload springs will support heavier loads and reduce sway. They will require less maintenance than air bags but will offer a stiffer ride quality while vehicle is not loaded. If you are looking for more durability and less hassle you should look toward overload springs.

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