EX­PLAINED: UP­PER CON­TROL ARMS

HAVE YOUR UP­PER CON­TROL ARMS GOT YOU DOWN IN THE DUMPS? AN AF­TER­MAR­KET SET MIGHT JUST BE WHAT THE DOC­TOR ORDERED.

4 x 4 Australia - - Contents -

MOD­ERN in­de­pen­dently sprung 4x4s are bet­ter in al­most ev­ery way than their older live-axle an­ces­tors. They’re more com­fort­able, more ca­pa­ble (thanks to a whole heap of elec­tron­ics), ride bet­ter, use less fuel, and al­low us to pound out pre­vi­ously un­heard-of kilo­me­tres with­out break­ing a sweat. Yep, on pa­per they’re just about per­fect; ex­cept all that ‘ex­tra’ stuff comes with ‘ex­tra’ com­pli­ca­tions. There’s no hid­ing the ob­vi­ous ones like need­ing a de­gree to even open the bon­net, but one that’s sprung up more and more with mod­ern sus­pen­sions is their com­pli­ca­tion in sus­pen­sion lifts.

The ba­sic premise still stands. Take out the stan­dard springs, put some longer ones in, and lift the body and chas­sis of your 4x4 a few inches far­ther away from the ground. But un­like the com­par­a­tively agri­cul­tural live-axles, in­de­pen­dent sus­pen­sions cause all sorts of is­sues when you start crank­ing them towards the skies. Af­ter­mar­ket up­per con­trol arms have taken the 4x4 scene by storm, promis­ing to fix what ails you, cure your lift­ing is­sues and grow curly hairs on your chest.

To get to the bot­tom of what’s what, we’ve spo­ken to some of the big­gest names in weld­ing to­gether con­trol arms to find out every­thing you need to know to not only lift your IFS 4x4 safely, but do it legally as well. We’ve roped in Troy Schip­per from Road­safe, the com­pany be­hind Black­hawk con­trol arms; Michael Hayes from Su­pe­rior En­gi­neer­ing and their ad­justable arms; and Cal Goodman from Calof­froad.

THE STRAIGHT AND NAR­ROW

WITH more and more 4x4 gear be­ing rolled in glit­ter and sparkles, it’s al­most too easy to get wrapped up in the what and less in the why. Be­fore lay­ing down your credit card de­tails on a set of new up­per con­trol arms it’s vi­tal to know why you do (or don’t) need them. Whether your 4x4 is sport­ing an in­de­pen­dent front end or live axle, in­stalling a sus­pen­sion lift will do two things: it’ll phys­i­cally lift your chas­sis and body away from the mount­ing point of your wheels and tyres, which frees up room for larger tyres and pro­vides ground clear­ance; and it’ll pivot the sus­pen­sion arms, link­ing the two to­gether. In solid axles, that pivot ef­fect is rarely an is­sue; the axle will roll, chang­ing the re­la­tion­ship be­tween up­per and lower bear­ings and throw­ing off the caster. A set of off-set bushes will fix the is­sue with­out too much fuss. In an in­de­pen­dent front sus­pen­sion things are a lit­tle more com­pli­cated. The twin-arm ar­range­ment means there’s not only caster ad­just­ment like a solid axle 4x4, but also cam­ber to con­sider. Lift­ing an in­de­pen­dent 4x4 even min­i­mally can knock all these align­ments out of spec and cause is­sues with ball-joint op­er­at­ing an­gles, clear­ance on both tyres, as well as other sus­pen­sion com­po­nents. Af­ter­mar­ket up­per con­trol arms are de­signed to al­le­vi­ate all these is­sues, get­ting the sus­pen­sion ge­om­e­try and align­ment back to fac­tory or bet­ter. Troy from Road­safe adds an­other point of­ten over­looked, “When the man­u­fac­turer gives a wheel align­ment spec­i­fi­ca­tion, it’s with­out raised height or in­creased tyre size. Larger tyres ab­sorb caster, forc­ing you to run higher caster than stock to re­tain the same feel.”

AF­TER­MAR­KET UP­PER CON­TROL ARMS HAVE TAKEN THE 4X4 SCENE BY STORM

LONG AP­PENDAGE OF THE LAW

WHILE Aus­tralian De­sign Rules are a fan­tas­tic im­ple­ment to en­sure the car next to you isn’t run­ning ply­wood sus­pen­sion arms, the chan­nels for mod­i­fi­ca­tions are of­ten murky and fraught with dan­ger. There’s been many peo­ple forced to unin­stall bet­ter han­dling sus­pen­sion or bet­ter per­form­ing brake up­grades be­cause the owner didn’t tick the right boxes. Be­fore a set of con­trol arms can be fit­ted to your 4x4 they need to be proven to meet or ex­ceed ADRS and OEM (Orig­i­nal Equip­ment Man­u­fac­turer) spec­i­fi­ca­tions.

There are two ways this can be done. The first is through the man­u­fac­turer it­self. If they’ve gone through the process to prove their arms meet or ex­ceed the fac­tory spec­i­fi­ca­tions they’ll be able to pro­vide you with the rel­e­vant pa­per­work.

“Na­tional Code of Prac­tice clas­si­fies these as a di­rect re­place­ment com­po­nent,” says Michael from Su­pe­rior En­gi­neer­ing. In most states this should mean no fur­ther pa­per­work is re­quired; al­though, if you do re­quire en­gi­neer­ing in your state it’s as sim­ple as sup­ply­ing the pa­per­work so no fur­ther test­ing is re­quired.

If the man­u­fac­turer hasn’t jumped through these hoops it means the arms in their cur­rent state aren’t le­gal for road use, no mat­ter how well (or poorly) they’re built. You’ll need to con­sult with an en­gi­neer and likely spend thou­sands in de­struc­tive test­ing to en­sure they’re up to spec. If the man­u­fac­turer can’t pro­vide rel­e­vant pa­per­work you may as well have got the pizza de­liv­ery boy to weld them, as far as the law is con­cerned.

“AF­TER­MAR­KET ARMS ARE ONLY LE­GAL IF ALL COM­PO­NENTS MEET OR EX­CEED OE”

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