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Anti roll bars

tja Oct 23, 2008

  1. tja

    tja Member

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    Thinking of changing anti roll bars - can I just change the front one (to Eibach), or is it better to swap both front and rear together?
     
  2. DPM

    DPM Site Sponsor Site Sponsor

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    You could just change the front but you'll feel more benefit doing both.

    Damian @ DPM
     
  3. tja

    tja Member

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    Damian, what kits include front and rear for B5 2WD saloon? It seems front bar on its own will increase understeer, yet I can't find a kit which has front and rear, only for 4WD - what's the point in front only?
     
  4. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    from the people around that have fitted them i think the general concensus is that they dont do very much

    Audi didnt uprate the standard Sport anti roll bar for the S4 or RS4, so i really dont think it needs changed for any normal road car.
     
  5. Blue_Thunder

    Blue_Thunder Well-Known Member

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    I fitted H&R ARBs to my S4 and it corners much flatter now.

    Only downside is that bump steer can be quite severe on uneven surfaces.
     
  6. Fraser

    Fraser Member

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    can the s4 ones go onto a tsport 2wd for example and a benefit is felt?
     
  7. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    the front is exactly the same part,

    rear might be a different shape due to the quattro system tho
     
  8. olds_kool

    olds_kool Active Member VCDS Map User

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    o.e front roll bars come in 3 different sizes so the thickest with some poly bushes and new links might make a difference
     
  9. PW-Motorsport

    PW-Motorsport Member

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    Some of the S4`s are suffering with rear sub frame cracks when fitted with the H+R thick anti-roll bar.

    The worst affected are the pre-facelift S4`s on standard springs and dampers. Cars with coilovers and anti-roll bars seem to be less affected.

    One supplier is offering support brackets to prevent this.
     
  10. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    TBH i suspect audi left them as they are on the S4 and RS4 because if you make them any stiffer it starts to affect the independance of the suspension.

    I suspect this is what Blue Thunder is talking about when he says it bumpsteers, its not actually bumpsteer (which is caused by a change in toe as the suspension moves thru its arc, and the A4's multilink system is designed specifically to remove that kinda change in the suspension geometry) Its caused by the anti roll bar stopping each spring/damper from doing their job.

    Basically when one side of the car hits a bump in the road, the arb is so stiff it transfers the force to the other side and compresses it too (this is what happens normally, but its a fine balance between reducing roll and hindering the suspension). This means that the spring is no longer properly holding the tyre onto the road surface and some nice understeer style loss of grip ensues because the cars tyres arent properly gripping the road.

    If your car doesnt already have the llargest audi ARB's (29mm front, 15mm rear) then fit those, otherwise spend the money elsewhere.
     
  11. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    oddly enough, i cant see any part numbers for a rear ARB on a FWD A4 B5, so perhaps they werent fitted with them at all?
     
  12. Broken Byzan

    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User quattro Audi A4

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    The 2wd isnt fitted with an ARB as it has a torsion beam axle. I have an S4 front ARB on my car and i could feel the difference. It was noticeably larger than the POS i removed.

    You can get a rear ARB kit for the 2wd but they are few and far between.I have seen a bar that bolts into the centre of the axle to eliminate flex and therefore act as an ARB but i cannot find the link, it was on Audizine i think
     
  13. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    was your car a sport though byzan?

    seems that non sport saloons had an arb around 26mm, non sport avants had a 29mm one, but its a different part number to the sport one.
    All Sport models, the S4 and the RS4 have the same (29mm) front ARB

    Its odd that it doesnt have one on the rear though, ive had quite a few vauxhalls with semi trailing torsion beam axles like the one on the back of the A4 that were fitted with antiroll bars from the factory. Nova and Corsa had a steel bar that run thru the middle of the V section in the middle of the axle, Astra and Cavalier had an external one that attached at the end of the trailing arm and ran along the outside of the axle.
     
  14. Broken Byzan

    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User quattro Audi A4

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    Mine was an SE

    No arb on there matey, like i said there is an aftermarket one that kind of bolts into the hollow section to stiffen it, but azine keeps crashing my pc
     
  15. PaulJC84

    PaulJC84 Owner

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    I fitted this kit to my A4 the other week.

    http://www.hotchkis.net/p-731-extreme-sport-sway-bar-set.aspx

    It is only for quattro models however. I did run just the front bar for a week with nothing on the rear as I needed to wait for new end links. I could tell the new front was a lot stiffer as the car was a lot flatter through the corners.

    Now I have fitted the rear as well and it is still nice and flat through the corners but the turn in is a lot sharper now.
     
  16. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    yer but stiff and flat is not good for uneven UK roads, for the reasons stated above.

    If all your doing is laps of a racetrack or something then fine. But point it down a B road, and the stock ARB's will provide more grip and less instability over bumps.
     
  17. PaulJC84

    PaulJC84 Owner

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    I think the stock bars had far too much give. I much prefer the new bars as have most people who have fitted them i believe.
     
  18. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    it'd be interesting to see if the car did actually have more grip though, or if it just felt nicer meaning you feel more confident to push it that bit further.

    I had an old astra with stock suspension and some decent sticky tyres. it gripped like **** to a blanket but felt horrible. I eventaully fitted some Konis and lowered it around 50mm, and it no longer felt horrible, but its limit of grip was still in exactly the same place. Ok it felt nicer and was more chuckable on backroads, but it didnt actually grip any more.

    I suspect that you may find your car feels nicer, but the negative impact of overstiff ARB's would mean that under certain conditions (lets say hitting a pothole or dip half way round a corner) your car could lose grip due to the ARB that it would otherwise not have lost.

    Its the same story with people who lower their hatches into the weeds then inform you with great conviction that it handles "on rails". The only issue being that their suspension geometry is now completely humped so that only half the tyre is actually in contact with the road, and theres no travel left in the suspension so that when it does acutally get driven properly it simply wont handle as well as it could.

    Also if its starting to crack subframes due to the stiffness of the ARB, you know theres something wrong!
     
  19. PaulJC84

    PaulJC84 Owner

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    Yes may be the car but I dont think I really drive the car at its absolute maximum anyway so if it feels nicer then thats better for me as will be more pleasurable to drive.

    Yes I have heard of people cracking their rear subframes with the H&R arb's. The H-sport kit comes with some subframe brackets so hopefully they reduce the risk of this.
     

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