I posted last night but my post seems to have disappeared (or possibly moved by admin?)

What is the difference between the OEM ARB and the uprated FARBs & RARBs sold by Jabba sport etc.

cheers

Alex

fabia doesn't have a rear arb as standard,the front arbs are thicker iirc but sit too low when fitted as far as i am aware,which is why not many folk run the fronts

wouldn't a thicker FARB tend to promote understeer? is that really something you want to be doing with a Fabia vRS..?

wouldn't a thicker FARB tend to promote understeer? is that really something you want to be doing with a Fabia vRS..?

There's a balance to be had. A thicker FARB may help if you've already got a RARB. The effect will be bigger if the car leans more. i.e. If you're running standard springs with a RARB, it may be too tail happy whereas with lowered cars, typically, the car corners flatter anyway.

Though once you change the springs and dampers, there's no guarantee that they retain the factory balance in the first place...

J.

What is the difference between the OEM ARB and the uprated FARBs

'bout £200 for couple of mm :thumbdwn:

and as said RARB aren't standard on a Fabia and someone'll be along shortly to argue the Jabba/Whileines item's aren't actually RARB but braces

Brace, anti roll bar, whatever you wanna call it - it should have been fitted as standard

Brace, anti roll bar, whatever you wanna call it - it should have been fitted as standard

i'm with you matey - i'll happily harp on all day about how good my Jabba one is! only for some smart **** to come along and go "uh i think you'll find due to it's lack of twisting movement its not actually an anti-roll bar"

That'd be me, then? Everyone's entitled to their own opinion - mine is simply that 'balancing' the handling by reducing the rear end grip isn't really my bag. If someone sold something that did it by increasing grip at the front, I'd be interested...

That'd be me, then?

:P;)

whatever it actually is and whatever it actually does i reckon it's great

If someone sold something that did it by increasing grip at the front, I'd be interested...

You'll be wanting a RARB then (may I recommend the Jabbasport one as it has done me proud).

If I may, here's a crudely drawn diagram which should demonstrate what it does:

In other words, the stiffer front end of the standard car puts more of the load on the left front tyre and reduces front end grip, while the total load remains the same it is more evenly distributed between the front and rear left tyres with a RARB fitted thus front end grip is improved (and rear end grip is slightly reduced).*

*I'm using 'grip' as a simplification for 'slip angle' as it amounts to the same effect.

source: http://en.wikipedia.org/wiki/Sway_bar

Here we go again... If you notice on the wikipedia article, there are droplinks connecting the unsprung components of the porker's suspension to the ends of the ARB; the middle section of which is connected TO THE CHASSIS. Feel free to post a pic of where it is exactly that the Jabba (or Whiteline) "ARB" does this. Until then, please feel free to seek further technical input from the last thread that explained what's actually going on with your rear axle!

What the hell are you wittering on about?

It stiffens the rear end (by reinforcing the torsion beam) - yes?

It reduces understeer - yes?

The diagram shows how stiffening affects load transfer - yes?

Please, do explain how you think the bar is reducing rear end grip, and reducing understeer, but NOT by evenly distributing load transfer. (perhaps it's the extra weight?)

I think this paragraph might clear up a few things...

"Because an anti-roll bar connects wheels on the opposite sides of the vehicle together, the bar will transmit the force of one-wheel bumps to the opposite wheel. On rough or broken pavement, anti-roll bars can produce jarring, side-to-side body motions (a "waddling" sensation), which increase in severity with the diameter and stiffness of the sway bars. Excessive roll stiffness, typically achieved by configuring an anti-roll bar too aggressively, will cause the inside wheels to lift off the ground during very hard cornering. This, of course, is only possible if the regular spring rate actually allows the outside wheels to handle the much increased load. This can be used to advantage, in fact many front wheel drive production cars will lift a wheel when cornering hard, in order to overload the other wheel on the axle, so limiting understeer."

As can be wonderfully proved in this photo

I knew it Ed, I could see that photo ending up on a thread like this, good timing mate.

The aftermarket RARB's are not a true ARB, the technicalties don't really matter here but they do their job well in stopping the roly poly effect of cornering. £100 well spent IMO.

If I'm (brutally?) honest I don't think the effect of the Jabba RARB on how my Ibiza feels to drive was worth the money, but the Cupra does sit a little lower than the vRS as standard and has different spring/damper rates (shorter, stiffer dampers and softer springs than say an FR), which makes me think that's maybe where people should be looking to improve the way their vRS goes around corners..? but as Gary says, you'll spend a lot of money trying to get it handle right

Right enough, I'm not denying they do SOMETHING to the handling, and that the effect is positive (up to the point where your inside rear wheel lifts, at least), but there's no point in posting links to info on independent rear suspension, because that's not what your Fabia has. However - much as I'd love to join in the debate all over again - it has been covered in minute detail already on here (and not so very long ago), so please spare a few kittens and use the search...

Beer has made me get more involved. Apologies for any speeling mistakes.

Both the Jabba and Whiteline R-ARBs attach to the rear twisting beam rather than the chassis. This isn't ideal but hey, short of fabricating metalwork for mounts somewhere in the region of the rear bumper, there's not a lot we can do about it.

Both types are intended to increase the roll stiffness of the rear suspension and both have "fan mail" stating that they do so.

That they attach to the beam means that the mounts themselves twist in and out of alignment. Both types have bushes to mount the bar but being an enthusiast type product, I guess neither use particularly compliant bushes. This mean the mounts will squeak, cause minor binding and wear out sooner causing clonking. There isn't a lot we can do about this unless a number of people want to donate £00's or £000's to develop a more engineered solution.

To end I state : I'd rather have a R-ARB than a Fabia without one. Either the Jabba or the Whiteline improve the handling balance of the car. :-)

J.

Loads of cars **** a rear wheel under hard cornering. Even touring cars do it. Why is it a problem?

Vindaloo - nail on head.

Apogee, you have it the wrong way round using the Porka's example (and it also applies to the front ARB of the Fabia).

The H frame of a torsion beam setup IS an anti-roll bar in of itself. Push on one side and the other side is also compressed. The strength of the TORSION BEAM is what dictates the stiffness, the standard Fabia's is made of cheese. Adding another spring bar to the torsion beam already there is, in reality, merely strengthening the anti-roll bar which is already there.

Does that make sense?

Does that make sense?

Of course it does, but what everyone always misses is that on the limit, you're not reducing the car's tendency to understeer, you're increasing its tendency to oversteer. (Note how Skoda-MSport's quote describes them as LIMITING understeer, not reducing / preventing it.) It might be semantics to you, but rather than being able to maintain adequate traction on all four wheels to make it round the bend at your chosen speed, what you're actually doing is promoting a four-wheel drift. This might be fine in touring cars where the drivers can control the car under these circumstances, but can you? I certainly wouldn't claim to be able to, but I do know what to do when I understeer.

It's similar to how people reckon they get 'lift-off oversteer' with them, when what they're actually experiencing is their front tyres regaining grip as they slow down, causing the front of the car to snap in the direction that the tyres are pointing, rather than the back of the car to step out in the opposite direction. Again, the sensation might be the same, but the actually behaviour of the car is fundamentally different.

Like I say, though, it's all here:

http://briskoda.net/fabia-i/these-rarbs-then/155980/