Hi,

I'm planing to buy a set of front and rear ARBs and the eternal question remains... 22 or 24mm?

I know that most owners opt for the 22mm version, but many only fits the rear ARB.

Since I'm fitting both, I'm wondering if the 24mm rear is still too stiff (prone to oversteer) comparing to the new 26mm front by comparation... or if the rear functions independently from the front and it's better to opt for the 22mm version anyway.

Can anybody help me on this?
Thanks

How do you want the car to behave, and what suspension do you have at the moment?

There is a noticeable difference between the 24mm and 22mm, i opted for the 22 as i found the 24 made the coupe a little tail happy but i didnt have an uprated front ARB to complement it so that might resolve that issue.

As stated above it depends what you want, road car or track car... I have a 22mm Rear bar and I'm of the opinion that you need to uprate the front a little, I've got a dedra 4x4 bar to fit.. Will post you my thoughts if your interested, cheers tim

front and rear ARB selection determines the front-rear balance of the car - which end will let go first at the limit. overstiffen the rear and u get oversteer at the limit, and understeer if u overstiffen the front.

that said, the coupe has the tendency for massive understeer. im using a 23mm rear bar with quite aggressive front camber/toe settings and im still seeing massive amounts of understeer. so i would suggest you go for a 24mm rear bar and leave the front one alone. i do agree that the car handles a bit weird with a stock front bar and an uprated rear bar - you get the feeling that the front is rolling a whole lot more than the rear - but you get used to it after a while.

a lot of coupe drivers complain of a twitchy ride even with stock ARBs and caution against using too stiff a rear ARB. i suspect that this is due to lift off oversteer which is quite easy to get with the coupe. if you're not careful the coop will even swap ends this way. but u shouldn't be lifting off mid-corner anyway if uv set up the turn correctly and i dont see a problem with this at the track.

redd

IMHO it also depends on which speed you're talking about.
In fast bends mine (22mm arb) is a TAD oversteering - just perfect.

In slow tight corners it's still understeering, and I don't see how anyone could change that with a weight distrubution of 65/35.

Hi all and thanks for your thoughts about this subject.

Answering some of your questions:

My set up right know is Bilstein shocks, Eibach lowered springs and SuperFlex bushes.

I expect the car to behave how a +200hp sportscar has to behave, not like the annoying bouncing on bad tarmac and major understeer.

I don't want it to massively oversteer also, for that I already have the sometimes frighting Pug205. (I know that isn't supposed to lift off mid-corner but it's sometimes needed, or you end with your front end on the back of some jerk who decided to occupy your lane just in front of you to pass the guy who was in front of him!)

So I'm guessing if complementing the rear 22mm with the front 26mm will make the understeer not to change... Or if the rear 22 will function on its own, even with a stiffer front ARB.

Thanks

I agree. In real life, on the roads, you have to lift off sometimes mid corner. If your car wants to swap ends every time you do this, sounds a bit dodgy.

What camber/toe settings do you have?

i run -1.5deg camber and 1mm toe out each side.

i do sepang F1 track a lot and i dont see oversteer even in the high-speed left-right turns 5 & 6, or the 11, 12, 13 combo.

but i do run a fairly compliant spring & damper setup - only stock springs on koni adjustable dampers. guys with stiffer suspensions - eibach springs, etc - may see more rear-end skittishness.

redd

What can it be a "normal" camber and toe setup for a lowered eibach/bilstein coop?

what suspension setup works for you also depends on how u drive. it takes some time to tune the car til it's just right for you. for understeery cars, u start with an aggressive front setup, go out give it a hoon and see how she behaves. if the tail wants to step out, u reduce front grip a bit - reduce camber, stiffer front bar, etc - to "balance" it out. if she still wants to understeer, u decrease rear grip - stiffer rear bars, springs, etc - to balance it out.

u will find that with the coop, the latter will predominate. u can also make minor adjustments via tire pressures but i usually only do that as a last resort.

redd

So many things comes to this equation, like what tires you may have and so on. I agree with Redd, try it out step by step!