Body Roll

[jerseypug 1]

the car was rolling so much that even in 4th gear through a corner the inside wheel would be spinning (atb diff) think i need bigger arb both ends

[Anthony 1,002]

A bigger front ARB will make the problem worse in my opinion, as it will effectively be trying to lift the inside wheel off the ground, significantly reducing its traction. You'd be better running higher poundage front springs, and losing the anti-roll bar completely if you want improved traction on the inside front wheel.

[welshpug 1,645]

run a proper diff? uprate the rear ARB would help, you need to look at it as a whole though and like anthony said simply upping the front arb will promote understeer if not balanced withan appropriate rear upgrade.

[jerseypug 1]

run a proper diff? uprate the rear ARB would help, you need to look at it as a whole though and like anthony said simply upping the front arb will promote understeer if not balanced withan appropriate rear upgrade.

i am running 250 lb springs at the moment with standard rear torsion and anti roll bars, i have 309 gti bars i can try.

[Vili 18]

i am running 250 lb springs at the moment with standard rear torsion and anti roll bars, i have 309 gti bars i can try.

 

I believe stiffening the front only has caused that most of the weight is sifting to outer front corner. If you fit thicker front ARB you will make it even worse. I think you should first fit thicker torsion bars, even thicker than the 309 gti.

[Tom Fenton 1,536]

^^^ is spot on, larger rear bars needed, maybe 22mm or thereabouts as a starting point.

[welshpug 1,645]

echo the comments above, your issue is the imbalance front to rear.

 

to use 309 bars you'd need a 309 beam, 309 bars are hardly any stiffer at all than 205 ones due to ther extra length, also no something I'd fit to a 205 rally car as the extra width limits suspension travel.

 

I'd just fit somehting like 22mm bars like Tom suggested, maybe 21.5 if the surfaces you run on are rougher, I'd hope you have decent rear dampers too.

 

 

 

I've driven a rally that is car setup similar to yours, 225 lb front springs on pts bodies, challenge rear dampers and a standard gti beam, didnt like it! my road car behaved far better, even without a diff.

[Cameron 16]

Just to echo all the comments above, by only stiffening the front end in roll you will have promoted understeer, you'll need to stiffen the rear to match. Fit thicker torsion bars to match the front first, 21mm or 22mm, then if you think it still understeers try a thicker rear ARB. As said, further stiffening the front end is the wrong way to go about it and you'll find you have even less front end grip!

[Baz 421]

Most common mistake that people make with 205's especially when fitting coilovers, whack on some heavier rate front springs neglecting to do anything with the back to match.

 

Easiest/cheapest fix would be to swap the front springs for some of a much lesser rate.

[Sobaru' 0]

and if you have a very heavy engine like a V6 could you use partner springsin at the front and for the back partner TB's and ARB to try and cure some of the understeer? Is this combination any good?

P.S sorry for posting this here but there is hardly any information on this subject.

[Cameron 16]

Easiest/cheapest fix would be to swap the front springs for some of a much lesser rate.

 

Would sort the handling imbalance out, but make the body roll worse! Depends where your priorities lie, spend more money and fix both problems, or save some money and only fix one.

Edited September 5, 2010 by Cameron

[Baz 421]

Good point yes!

[jerseypug 1]

seems like everyone is agreed on stiffening up the rear. thanks for all the advice. our main rally is on smooth tarmac, i run dunlop x22 moulded slicks, just to point me in the right direction, i know trial and error is the best way but not really possible, should i use 22mm torsion bars and what size rear arb?

[Cameron 16]

Rear ARB choice is completely up to you, as it's to fine tune the balance. If you think it understeers too much, fit a thicker ARB, if it's fine then leave it. My 205 still has the standard rear and gets a reassuring amount of power oversteer without being unpredictable. But that's my personal preference, some people will be happier (and therefore quicker) with the rear being extremely loose.

 

As someone said earlier, you'd be better off fitting a plate diff too, as the ATB's aren't too hot if you're lifting the inside wheel. They're more suitable if you plan to use the car as a daily & track hack, for a dedicated track / race car they aren't as good.

Edited September 5, 2010 by Cameron