Rear ARB and springs

[FlyInMySoup]

I fitted a rear arb and 20% stiffer springs to my car (Caterham 7 live axle) to overcome understeer in fast turns. It's worked a little too well so am going to soften it off 'a bit' for next season. I'm pondering how best to achieve this, the arb is on max soft already so I could either throw away the arb or leave it on and soften the springs. I'm tending towards the latter as I think it will improve weight transfer to the rear when I get on the throttle without compromising roll stiffness. Is this a reasonable analysis or just nonsense? Thoughts appreciated.

Thanks

[phoenix]

Do you have a LSD fitted? And did you notice any lifting of the inside rear wheel with the stiff rear setup?

If you suffered from this it would probably be better to loose ther rear ARB altogether, but if you didn't then I would suggest you test it anyway with the 20% stiffer springs but without the rear ARB fitted and see how it goes.

Second test would be original springs with the ARB fitted.

One of these setups is likely to give a better time than the other and will give you more indication of what to do next. i.e. the 20% stiffer springs with maybe a softer rear anti roll bar or the softer springs with the ARB you have.

The third alternative is to tune the front end to match the rear, by adding a stiffer - and ideally adjustable - front anti roll bar. Only use this method if you are happy that the higher level of roll stiffness is not going to compromise any other aspect of the handling and grip - such as traction and behaviour over kerbs etc. A stiffer car will be more 'edgey' and you may prefer the diveability of the softer (in roll) setup.

[FlyInMySoup]

Thanks for the advice, appreciated.

[morninggents]

Originally Posted by FlyInMySoup

Thanks for the advice, appreciated.

Trouble is that you changed two things at once, originally, so you don't know which of them works best.

If you go testing or do track days then do as Phoenix suggests.

[BJD]

Also, if poss try and get some test rather than track time so you can time a few laps. Change one thing at a time and let the stopwatch/lap timer tell you whether its getting better or worse, its very difficult to make an accurate subjective judgement about what is better or worse when the difference is only perhaps a second or two over a lap. What you are gaining time-wise in one type of corner you may be losing more on other corners. Myself and my brother did some similar ARB/spring testing on a track day, I'd give the car a few laps and come in saying it was better, he'd try a few laps and say it was worse. Without a stop watch, although interesting to feel the difference that the changes made, it was a waste of time in trying to make the car quicker overall based on subjective guesswork.