Air Suspensions Have Hit MainstreamHot Rodding. We Explain EverythingYou Need To Know About Them.

By Marlan DavisPhotography: Marlan Davis, Scott Killeen, and the Manufacturers

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A sea-change in hot-rod sus-pensions is sweeping across thescene: replacing conventionalmetal suspension springs withair springs, often controlled bysophisticated air compressorsand self-leveling electronics.Whether it’s for looks, easyride-height alterations on thefly, handling improvements, orbetter load-carrying ability, airsuspensions combined withhuge wheels and tires are moremainstream than ever. To getthe lowdown on air suspension,HOT ROD consulted leadingair suspension specialists,including Air Ride Technolo-gies’ Bret Voelkel and Total CostInvolved’s (TCI) Sal Solorzano.These outfits are among the

leaders in bringing practical,bolt-on air-suspension technol-ogy to the hot-rodding main-stream. They shared theirexpertise on what it takes toinstall a first-rate air suspensionon your hot rod.

WWHHAATT IITT IISSAn air suspension replaces con-ventional springs with airsprings similar to those on big18-wheel semitrucks. Conven-tional coil-spring suspensionsare the easiest to upgrade, withthe airbags slipping right inplace of the coil springs andoften bolting to proprietarybolt-in brackets supplied by theaftermarket manufacturer. Air-spring design has progressed to

the point that pioneer compa-nies like Air Ride Technologies,TCI, Air Lift, and others havedeveloped bolt-on kits for mostpopular coil-spring cars andtrucks. There are even air-spring solutions for leaf-springand torsion-bar suspensions.

WWHHYY YYOOUU WWAANNTT OONNEEAn air suspension offers at leastfive major benefits:

Tunability: Air suspensionshave a wide tuning range forspring rate and load capacity.Weeks of conventional springand shock tuning can be pain-lessly compressed into a fewminutes via in-car adjustability.Getting the ride height, load,and rate on a coil spring right

on the first try is a hit-and-missaffair, but an air suspensionprovides a much broader enve-lope, so precise selection isn’t ascritical as on a conventionalspring.

Handling: Most air springsare progressive. The more theycompress, the stiffer they get.Combine this inherent progres-sive spring rate with in-caradjustability, and the result isenormous performance poten-tial. Tuning for conditions isquicker and faster. In a sophisti-cated handling application, theair spring should be coupledwith shocks adjustable for bothrebound and compression andcarefully selected antisway bars.

Performance customiza-

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>>The current state-of-the-art in an integrated, elec-tronically controlled air suspension, Air Ride Tech-nologies’ LevelPro system uses a combination of

ride-height sensors and air-pressure sensors toquickly achieve and maintain the desired, user-

selected ride height. Here, it’s installed on an Art Mor-rison repro ’53-’62 Corvette chassis. Check out thephotos on the next two pages for detailed informa-

tion about what the arrows are pointing to here.

>>With their greater load capacity, double-convoluted air springs areusually used up front. The latest development is Air Ride Technolo-gies’ ShockWave, a patented combination of an air spring and ashock absorber that’s similar to a high-tech racing coilover. It makesreplacing original factory coil springs easy by eliminating the needfor shock-absorber relocation.

>>A ride-height sensor near each wheel provides to the computerinformation on the vehicle’s actual ride height.

tion: Everyone has his own per-sonal idea of how his carshould ride and handle. With an airsuspension, these wishes can beaccommodated with little or nocomponent changes. By adjust-ing air pressure and shock valv-ing, you can make the same carbe soft and comfortable, firmand tight . . . or anywhere inbetween.You can drive the carcomfortably to the track, firmup the air pressure and shockvalving to go racing, then read-just the pressure and valving toreturn home in comfort.

Stance: Air suspensionsmake it easy to lower the car soyou can look cool. At the farend of the coolness spectrumare spark-throwing minitrucksand lowriders, but today, theyrepresent only a small segmentof the market. Far more typicalis the guy who just wants tolower his car or truck a reason-able amount for better lookswithout sacrificing any drive-ability or durability. Most kitscome set up to deliver a normalride height that’s several incheslower than the stock springs.Regardless of how low the caris, air suspensions make it easyto raise the car back up for nor-mal cruising, getting into gasstations, or even rolling ontothe trailer.

Load carrying: This is theoriginal commercial applica-tion for air suspensions: help-ing 18-wheelers carry heavyloads while improving drivercomfort. Although probablynot the main reason for switch-ing over on a pure hot rod, itdefinitely is one solution formaking your dualie tow truckmore driveable under varying-load conditions. In fact, somenew SUVs now come with airsuspensions.

AAIIRR--SSPPRRIINNGG DDEESSIIGGNNToday, most air springs aremade by Firestone, which pio-neered their use on big trucks.Three basic types of air springsare available: the double-convoluted, the tapered-sleeve,and the rolling-sleeve. Thedouble-convoluted design

looks like a large double cheese-burger and generally has moreload capacity, a shorter stroke,and a more progressive springrate that’s best suited for use onmost front suspensions wherethe spring sits considerablyinboard of the suspension’sload point, which has the effectof multiplying load-capacityrequirements while dividingtravel requirements. Tapered-and rolling-sleeve air springsare smaller in diameter with alonger stroke and a more linearspring rate; they’re best suitedfor most rearend applicationsbecause there are more travelrequirements and fewer load-capacity requirements.

FFRROONNTT SSUUSSPPEENNSSIIOONNShock relocation was usuallyrequired with most first-generation air-spring setupsbecause there was no hollowarea in the air spring’s center toaccommodate the stock shock-absorber mounting locationthat typically ran through thecenter of the coil spring. Kitsdesigned for conventional airsprings come with shock-relocation mounts and newcontrol arms as needed. This isan affordable and straightfor-ward solution, but in someinstances, relocating the shockcan result in wheel/tire clear-ance issues, especially withtoday’s huge wheel-and-tirepackages.

As air suspensions evolved, ahigher-end installation wasdeveloped based on coilovershock/spring combos but withan airbag replacing thecoilover’s coil spring. Thesesetups tend to be more expen-sive but offer the advantage ofeasier installation, better looks,and more wheel-and-tire clear-ance.

On the other hand, depend-ing on the chassis, a coilover-like design could yield lessoverall wheel travel comparedwith a separate air spring andshock setup. Reduced wheeltravel requires a stiffer bag toavoid bottoming out the sus-pension at a given ride height.Under these circumstances, if

>>ShockWaves are available as single-adjustable (rebound only)units or in the preferred double-adjustable style shown here withseparate rebound and compression adjustments. Double-adjustable shocks are more easily re-optimized when ride height,air-spring height, and air-spring pressure changes.

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>>A compressor andreservoir tank allowquick in-vehicle altitudeadjustments. They canmount anywhere on thevehicle, but the mostpopular locations areunder the car or in thetrunk. Be sure to pro-tect the compressorfrom direct road sprayand debris damage.

Run heavy-gauge wire to the compressor and use a relay to protect thelow-amp pressure switch.

>>Electric solenoidscontrolled by adash-mountedswitch or an ECU (onhigh-end setups likethe LevelPro) areused to inflate ordeflate the springs.Solenoids eliminateunderdash air lines,

plus, they can be remotely mounted in the trunk or under the car. Mountelectronic components in a protected area away from moisture.

>>Air springs can be made to work in conjunction with old-school leafsprings, but most custom rods take the opportunity to upgrade to amodern four-link suspension at the same time. Virtual bolt-in conver-sion kits requiring only minimal axle-bracket welding are availablefor most popular chassis.

>>With more travel and lessspring rate than the convo-luted style, a tapered- orrolling-sleeve air spring isusually preferred for sup-porting rear suspensions.This 7000-series Shock-Wave replaces a conven-tional coilover on a four-linkor ladder-bar–style rearsuspension.

>>The LevelPro’s in-cockpit control paneloffers three preset lev-els. Level 2 is typicallyprogrammed for a car’sstandard highway rideheight and is the default set-ting whenever the vehicle isstarted. Additionally, manual inflate and deflatecontrols as well as an air-pressure display areavailable for each corner of the vehicle.

ultimate ride quality is para-mount, a separate bag andshock setup might be prefer-able.

RREEAARR SSUUSSPPEENNSSIIOONNFor cars already equipped withrear coils, changing over toairbags is straightforward. Theyoften go right where the oldsprings used to sit, although insome cases, different springseats may be needed (if so, theycome in the kit). Shock-within-airbag designs are available aswell, but additional mods maybe required to install them.

Leaf-spring cars have two

options. The simplest conver-sion is to remove several leavesfrom each spring pack andinstall air springs between theaxlehousing and the vehicleframe. Residual leaves are stillneeded to locate the rear axle,but airbags now perform theprimary load-bearing function.On an old car with worn-outleaf springs of uncertain dura-bility and capability, the plan (ifyou can afford it) is to replacethem entirely by moving up toa four-link suspension. Majoraftermarket outfits offer pre-made conversion kits that boltright into popular leaf-spring

>>Triangulated upper four-bar links typically fit most cars betterthan parallel links. Laying out a ladder-bar or four-link rear suspen-sion is similar when using an air spring, a ShockWave (air springwith integral shock), or a conventional metallic spring. Air suspen-sions make it easy to adjust for a large range of vehicle weight—simply vary the air pressure.

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>>Air suspension isn’t just for profilin’ or carrying loads. Compare thered ’67 Chevelle with the blue ’66, both with similar motors andBFGoodrich g-Force tires. The red car with its stock suspension leanslike a drunken sailor. The blue car has Air Ride’s full air suspension, anti-

sway bars, and control arms, plus taller Fat Man spindles—it pulled1.12 g on the skidpad and was 14 seconds quicker around the two-milePutnam Park road coarse in Mount Meridian, Indiana (1:26 comparedwith the red car’s 1:43).

cars with only minor weldingrequired for new brackets onthe axlehousing. Universalweld-in setups are offered forrace cars and custom applica-tions.

Depending on the physicalconstraints of the chassis layoutand body clearance, the four-link kits’ upper links may beeither triangulated or parallel inrelation to the lower links. Gen-erally, parallel four-links fit bet-ter in trucks, while triangulatedsetups are more suitable forcars. For some chassis, bothparallel and triangulated four-link configurations are avail-able. If you have a choice, ahandling or primarily street-driven vehicleusually performs better with atriangulated four-link; a parallelsetup is generally the ticket for apure drag-racer/straight-lineapplication.

CCOOMMPPRREESSSSOORRSSAt their most basic level, airsprings can be inflated usingexternal shop air just like an oldair shock, but that obviates oneof the main benefits of this typeof suspension: in-use adjusta-bility to compensate for chang-ing road conditions, vehicleloads, or intended use. Every

time you add load without on-board air—be it fuel, people, orcargo—you have to track downan air hose.

Realizing full benefits fromthe adjustability offered by airsprings really requires an on-board air source. With air sus-pension, ride-quality tuning isaccomplished incrementally,with very small air-pressurechanges. Air springs have rela-tively low volume, so it is diffi-cult to inflate or deflate themwith external air in smallenough increments to fine-tuneride quality.

An on-board air system con-sists of at least one air compres-sor, probably a storage tank,and some sort of control sys-tem. A cost-effective and rela-tively simple solution that providesreasonable ride and handlingbenefits would be a 2-gallontank kept full by a single com-pressor. On the other hand, ifyou want the car to go up anddown in two seconds, on aheavy car it could take as muchas a pair of 150-psi compressorsand two or more 5-gallontanks, huge industrial air valves,and 3⁄4-inch feeder lines.Yet suchan extreme setup could createjust as many fine-tuning hassles

as a basic external-fill setup: Ona fast-acting system, every pushof the button may result in a20-psi change in air pressure.

AAIIRR LLIINNEESSCommercial, DOT-approved,plastic air lines originally devel-oped for big trucks are standardin most kits. They provide aneasy, affordable solution to con-necting the compressors to theair springs. Typical operatingpressures range from about 75to 150 psi, well within the capa-bilities of such tubing.

For the custom look, you canfabricate stainless hard line, justas in a brake or fuel system,connecting it using typical ANflare nuts and pipe adapters. Atsuspension travel points, flexi-ble hose would be needed in anotherwise hard-lined system,just as it is in a brake system.Also like in a brake system,braided stainless steel Teflon-core hose is preferred overbraided synthetic rubber-corefuel/oil-line hose.

TTWWOO--WWAAYY VVEERRSSUUSSFFOOUURR--WWAAYYWhen air suspension was firstintroduced to hot rodders inthe mid-’90s, a two-way controlsystem was the standard

method of inflating and deflat-ing the suspension. In otherwords, both air springs on eachaxle were hooked together. Thiskept things simple, requiringonly one control valve per axle.However, it quickly becameapparent that during cornering,the outside (or loaded) airspring tried to transfer air tothe inside (unloaded) spring,magnifying body-roll issues.Sometimes the problem can beminimized on a light car byinstalling big antisway bars, butnowadays, nearly everyone usesa four-way system, whichplumbs and controls eachairbag separately. Although thisrequires an individual controlvalve and air line for eachspring, it cures all air-transferproblems, plus it allows precisecontrol over vehicle ride heightto compensate for varyingweight, suspension bind, oralignment changes. Think of afour-way setup as somewhatakin to weight-jacking on anoval-track car.

CCOONNTTRROOLL SSYYSSTTEEMMSSPurely two- and four-way man-ual controllers are available forthose on a budget. Manualsetups typically use pneumaticvalves mounted to a panel with

>>Three basic air-spring configurations are in use today. From left theyare the rolling-sleeve, the tapered-sleeve, and the double-convoluted.While there are many variations for each configuration, in general, theload-bearing ability increases progressively with each basic design.

>>Air suspensions canrange from stock replace-ment bolt-ons to wholenew front clips. Longknown for trick street-rodchassis, TCI now offers acomplete new front sub-frame for early ’62-’67Chevy IIs. Here it’s shownwith TCI’s separate shockand air-spring setup. Spac-ers are available as shownto help develop the properairbag installed height.

>>Although pricier, the shock-within-airbag design installs easier. For TCI’s’62-’67 Chevy II subframe, it fits right in place of standard coil springs.This deluxe package adds Fat Man spindles and rack-and-pinion steering.Note how at ride height the bag’s end plates are parallel and in line withthe shock mounts. Moving the spring toward the ball joint raises its rate.

>>MacPherson strut? No problem. Air RideTechnologies offers AirStruts that directlyreplace the stock factory struts for manypopular, late-model cars. These struts haveslotted spindle mounting holes and eccen-tric adjuster bolts that prevent the need forthe special camber/caster plates usuallyrequired to restore proper wheel alignmentat lower-than-stock ride heights.

>>Air springs can be used on a leaf-spring suspension. Air Ride Tech-nologies’ bolt-on AIRoverLeaf sys-tem offers great ride quality andextra load-bearing capacity withoutthe need for re-engineering yourvehicle to accept a four-link conver-sion. Several leaves must stillremain in place as an axle-locatingdevice.

>>Some cars need extra clearance to properly install air suspensions.Air Ride Technologies’ tubular Strong Arms have dropped mountingpoints, plus they allow dialing in a little more caster. In some cases,optional matching upper arms are available that produce more nega-tive camber while preventing ball-joint bind with today’s popular tallerreplacement steering knuckles.

“I can service nearly any car with fourdifferent air springs, front or rear.” —Bret Voelkel, Air Ride Technologies

a pressure gauge. A moresophisticated approach withless underdash clutter is to useelectric solenoids controlled bya switch or computer. The last3-4 years have seen the intro-duction of various aftermarketactive electronic height-controlsystems that attempt to main-tain a set ride height as thevehicle drives down the road.An electronic height-controlsystem adds a computer plussensors to control the electricsolenoids. Both pressure-basedand ride-height–based elec-tronic control systems are avail-able.

PPRREESSSSUURREE--BBAASSEEDDSSYYSSTTEEMMSSWith pressure-based elec-tronic-control systems, thecomputer must rely on air pres-sure alone to extrapolateproper air-spring position,which should then theoreticallytranslate into the position ofthe suspension, which shouldthen (again, theoretically)translate into the ride height ofthe vehicle. Obviously, that’s alot of translations, interpola-tions, and assumptions.Although it may work fine on avehicle that seldom sees loadchanges and is reasonably wellbalanced, for many vehicles,there’s a major drawback:When any change occurs to theload an air spring sees, theassumption that any given airpressure will equate to a spe-cific ride height may no longerbe valid. Many transients cancause a load change: actualweight change via the additionor subtraction of passengers,luggage, or fuel; the vehicle sit-ting on an incline or pothole; or even general sus-pension-geometry or suspen-sion-bind factors that end uprequiring more air pressure toraise the vehicle than they do tomaintain a specific ride height.

Active pressure-based sys-tems may not react properlygoing through a long, sweepingturn (an interstate cloverleaf orany dynamic maneuver thatincreases the load on one side

of the vehicle for a significanttime period). Under such con-ditions, an active pressure-based system attempts todeflate the outside (loaded) airspring and inflate the inside(unloaded) spring, magnifyingbody roll and handling prob-lems just like the old two-waysystem.

RRIIDDEE--HHEEIIGGHHTT––BBAASSEEDDSSYYSSTTEEMMSSRide-height–based systems uti-lize separate sensors thatdirectly measure the actualposition of the vehicle’s suspen-sion, thereby eliminating sev-eral assumptions made on apurely pressure-based systembecause now precise information on the rela-tionship between the suspen-sion and the chassis is availableto help the computer deter-mine the vehicle’s ride height.But there’s still one problemknown as cross-loading. Thishappens when the ride height isachieved with radically differ-ent air pressures on each cor-ner. Normally, any side-to-sideair-pressure variations shouldbe held to 20 percent or less; yetit is possible to fool a pure ride-height–based system by overin-flating two diagonal cornerswhile leaving the opposing cor-ners significantly underinflated.The computer keeps the carlevel, but the handling charac-teristics suck.

CCOOMMBBOO SSYYSSTTEEMMSSThe solution is to combine pressure-based and ride-height–based leveling in thesame system. Each serves as acheck on the other. This is whatAir Ride Technologies has donein its new LevelPro system. Tosave money initially, the setupcan first be configured as apressure-based system only,and the ride-height sensors canbe added later, if needed. Level-Pro systems also include theability to program three differ-ent suspension heights into thecomputer—low (for profiling),normal (for touring and rac-ing), and high (for clearing

>>TCI is developing a four-link air suspension for ’67-’69 Camaros.The links are parallel, so the finished kit will include a Panhard bar tokeep the rear centered in the car. The air spring is Air Ride Technolo-gies’ ShockWave 9000 with a tapered-sleeve airbag bellows. Thisallows a softer spring rate, longer travel, and a lower load capacitysuitable for rear installation.

>>Air Ride Technologies offers a plethora of bolt-in rear four-link conversion kits for a wide variety of cars and trucks. This kit (PN ABAR20400) fits the ’60-’64 fullsize Ford Galaxie. Front and rearkits are even available for Chryslers.

>>There is virtuallyno limit to retro-fitting air suspen-sions onto just aboutany vehicle. Here AirRide Technologies’ShockWave 9000 isinstalled on a KugelIRS. Typically, KugelIRS units use twocoilover shocks perside, one on eachside of the driveaxles—the Shock-Waves fit right inplace.

obstacles like speed bumps).Simply punch a button, and thecar raises or lowers to a presetlevel yet can still compensate ateach preset for changes in fuelload, passengers, or cargo.

CCUUSSTTOOMM IINNSSTTAALLLLAATTIIOONNSSComplete air-suspension kitsare available for mainstreamclassic musclecars as well asmodern, high-performancefactory hot rods, trucks, andSUVs. Because they are alreadyproperly engineered and sci-enced out, these kits are pre-ferred over mixing and matchingcomponents from scratch. Pre-engineered air-suspension sys-tems address all the issues ofair-spring installed height,shock installed height, ball-joint travel, driveline angles,ground clearance, tire clear-ance, and other parameters thatmust be considered whenbuilding a safe, functional sys-tem.

For less popular vehicles, forwhich no ready-made kit isoffered, it is feasible for anadvanced hot rodder to cus-tom-engineer a viable air-sus-pension system. Fundamen-tally, it’s no different fromengineering traditional suspen-sion, except air springs replacemetallic springs. It may actuallybe easier because air springshave a greater operating enve-lope in terms of ride height andload capability than traditionalmetallic springs.

Bearing in mind the differentair-spring designs and systemconfigurations in the precedingdiscussion, it is important tomatch the air spring to thevehicle’s weight capacity andsuspension travel. A dualie thattows a 48-foot trailer obviouslyneeds a larger air spring thanthe rear of a ’69 Mustang. Air-spring-suspension experts canusually provide a good ballparkair-spring recommendationgiven reasonable informationabout the vehicle’s characteris-tics, desired maximum andminimum height, and how fast

it needs to cycle up and down.Identical springs and shocks

may not always yield identicalresults in two different applica-tions, even if the weight andinstalled height are similar. Asalluded to earlier, on a frontsuspension, the spring-mountlocation on the control armexerts a leverage effect, multi-plying the theoretical springrate as seen at the wheel. Justlike an engine rocker arm,increasing the distance of themount from the arm’s pivotpoint (moving it closer to theball joint) yields a higher ratio,which multiplies the springrate. Increasing the angle of theshock also requires more springto maintain an equivalent rideheight.

Once the air spring has beenselected, it must be mounted inthe vehicle. Every air spring hasan optimum design ride heightwhere it delivers maximumperformance. This spring-height dimension (availablefrom the air-spring manufac-turer) should be synchronizedwith the intended ride height todetermine how to mount theair spring in the car. Themounting point must alsoallow for sufficient suspensiontravel, tire clearance, groundclearance, and appropriate dri-veline angles. Maintain ade-quate clearance between the airspring and other compo-nents—abrasion is death tothese otherwise very durableunits.

A variety of premade univer-sal brackets is available fromair-spring kit makers. Air-spring units, like Air Ride Tech-nologies’ ShockWaves thatmount like a coilover shock, areeasier to install with propergeometry than separatelymounting a conventional sepa-rate air spring and shockabsorber.

The vehicle should bemocked up at its intendedhighway ride height. At thispoint, you should maintain atleast 41⁄2 inches of ground clear-ance and have adequate sus-pension travel—at least 3

>>TCI offers billet air springs to replace the standard coilsprings offered with its completely fabricated street-rod chas-sis. They’re available for the rear of these chassis as well.

>>Over the years, leading air-suspension manufacturers,such as Air Ride Technologies, have continued refining once-generic commercial-grade air-suspension parts specificallyfor hot-rod use. A typical state-of-the-art control system nowincludes bubble-tight solenoids, DOT-approved air lines andfittings, electronic ride-height sensors, and computerizedcontrol units.

>>Air reservoir tanks come in many sizes. The main benefit ofa larger tank is quicker rise time. Most hot rodders use a sin-gle 2- to 5-gallon tank. Some hard-core truckers who want afaster inflation speed may use larger or multiple tanks andcompressors as well as larger-outside-diameter air lines.

inches in compression and 2inches in rebound. Be sure theair spring’s end plates arealigned and parallel at rideheight.

Firestone double-convolutedair springs don’t require abumpstop to avoid damage,however, your specific applica-tion may need a bumpstop tomaintain safe ground clearancewhen deflated. For tapered- orrolling-sleeve air springs, abumpstop and an extensionstrap (either a limiting strap ora shock absorber) must be usedto prevent the air spring fromexceeding its design com-pressed or extended dimen-sions or the spring will fail.Finally, set wheel alignment atthe car’s normal running ride

height, understanding that itwill change slightly when thesuspension is in the raised or lowered position.

SSUUSSPPEENNSSIIOONN TTUUNNIINNGGShocks and antisway bars arejust as important on an air sus-pension as they are on a con-ventional suspension. Whethermetallic or air, a suspensionspring’s primary purpose issupporting the vehicle’s weightat a given ride height. Shockscontrol suspension oscillation.Antisway bars control vehiclebody roll to minimize suspen-sion-geometry changes andweight transfer during corner-ing.

Air-suspension experts rec-

ommend supporting the vehi-cle with as soft a spring as pos-sible, relying on proper shocksand antisway bar–tuning tocontrol oscillation and bodyroll. This maintains ride qual-ity—one of the main reasonsfor installing air springs—whilealso enhancing cornering per-formance.

After you select basic parts toget in the ballpark, the realadvantage of an air suspensioncomes into play. Dialing in atraditional suspension for theexact vehicle load, road condi-tions, driving style, and driverpreference requires time-con-suming component changes.With an air suspension, fine-tuning can be accomplishedwith the push of a button and

>>Plastic air lines are standard inmost kits. The end fittings simplypush on with no tools required.Just be sure to cut off the linessquarely; Air Ride Technologiesoffers a special cutting tool tospeed this up. Quarter-inch linesare the standard for most sys-tems, but up to 3⁄4-inch lines withmultiple compressors have beenused by those who want their carsto hop.

>>Control systems can be as simple or as complex as you want to make them.This is Air Ride Technologies’ ultimate four-way LevelPro auto-leveling systemwith all major electronic and pneumatic components called out. Nearly all con-nections are direct plug-ins to simplify installation.

the twist of a knob.

DDUURRAABBIILLIITTYYQuality air springs have beenproven in millions of miles ofheavy-duty commercial vehicleuse for more than 70 years.Firestone has tested its air-spring designs for tens of mil-lions of cycles—that translatesinto a 40- to 50-year life span.So long as the air spring isn’trubbing against anything andis at least 2 inches away fromhot exhaust pipes, it ought tooutlast the vehicle.

The most common problemis air leaks, usually caused byimproper installation.Voelkelsaid,“The simple use of threadsealer on the fittings will pre-vent 97 percent of all leaks. Theonly other place there couldpossibly be a leak would be inan air valve if it gets any assem-bly debris or Teflon tape in theorifice. Although it is theoreti-cally possible for an air springor ShockWave to leak, in the 10years we’ve been in business, Ihaven’t found one yet.”

Although rare, anythingmechanical can break—be itmetallic coils or an air spring.When engineering a customsetup, be sure there will be ade-quate ground and tire clear-ance if the air suspension fullydeflates—at least enough to getyou over to the side of the roadwithout scraping the frame.

Properly engineered anddesigned, air springs are doingfor suspensions what EFIengine-management systemsand overdrive trannies havedone for the drivetrain.Yes,there’s a learning curve; yes, thesophisticated high-end systemsare pricey—but they’re yetanother step forward in mak-ing it possible to truly build acar that you can race on Sun-day, drive to work on Monday,and cruise the parking lot onFriday night. HRM

SSOOUURRCCEESSAAIIRR RRIIDDEE TTEECCHHNNOOLLOOGGIIEESS;; Jasper, IN;812/481-4787; www.ridetech.com

>>Air Ride Technologies’ four-way BigRed solenoid package makes short work of compressor-system installa-tion and plumbing. Designed specifically for air suspension, its bubble-tight solenoids provide reliable, leak-free performance. The free-flowing, large-capacity valves are designed for fast ride-height adjustments.

>>An optional hand-held remote-controlunit permits out-of-vehicle control overAir Ride Technolo-gies’ LevelPro system.

“An air suspension’s ability to quickly change vehicle rideheight is great because today’s hot rods are set up low atride height, and with an Air Ride, you can just add air toget over speed bumps, get up driveways, or put your caron the trailer.” —Sal Solorzano, TCI

“The ride quality of an air suspension is typicallymuch better than conventional coil springs orcoilovers because the driver is able to quickly tunethe load capacity of the air spring to the exact load ofthe vehicle and his driving style.” —Bret Voelkel, AirRide Technologies

Posted with permission from the January 2007 issue of Hot Rod ® www.hotrod.com. Copyright 2007 PRIMEDIA Inc. All rights reserved.For more information about reprints from Hot Rod, contact Wright’s Reprints at 877-652-5295