Anti Roll Bars - Nerd Alert

[andyf]

The first thing to check is that you have a consistent roll centres on the front and the back of the car. If they are not then you'll get one of the inside wheels picking up under hard cornering. My cousin's stock car was so far out (The front roll centre was on the floor) that it picked up the front inside wheel nearly a foot off the ground! Then look at the spring rates to get the balance required between comfort on bump versus roll resistance as well as the balance front to rear (oversteer versus understeer). Then finally add the ARBs to fine tune the setup. For a road car the ARB will allow you to run softer more compliant springs and still control the roll.

On my cousin's car we pushed the inboard lower wishbone mounts up about two inches (the top hole that was available), which brought the front inside wheel back down to the ground and then used the rear ARB to fine tune the balance and it transformed the car from a dog to an event winner

[Fury1630]

I'm not intending doing anything at all because I like it as it is. I was just interested after comments made on another thread (raised here to avoid further trashing of someone else's thread).

Everybody seems to be saying the same - get the geometry as good as possible & use A.R.B.s if required to fine tune.
In my case, they're not.

Thanks all.

[DJ.]

Hope you don't mind me adding a picture to this thread Tony

I've had another look at those photos and none of the casr exhibit the sort of roll I got with my Elan.
I've taken a photo of the framed print I have, so sorry for the poor quality:

elan_roll.jpg (358.29 KiB) Viewed 1918 times

[Crunchie Gears]

Tony

As an engineer you will like this article which explains about roll centres, centre of gravity, the moment between the two and how this makes the car roll and the relationship between front and rear roll centres.

http://www.meganracing.com/tech/faqs.as ... Suspension

I think you might be drawing this up

[Toltec]

For a road car the ARB will allow you to run softer more compliant springs and still control the roll.

This is a key point, if you add an arb you will probably need to reduce the spring rates, if you don't you will get less grip and so more understeer. Adding an arb to the rear of a fwd hatch is commonly done to give more oversteer.

I had a front arb mount break when I was on a track day, effectively removing it, which lead to hilarious amounts of 'drifto', not to mention a warning from the marshalls.

[pigeondave]

If you want to look at roll centres this is a good little tool

http://www.vsusp.com/

This is a good site to learn about the different aspects
http://www.super7thheaven.co.uk/glossary/

basically my understanding of what the ARB does is to reduce roll, the reduction in roll means that the tyres are more evenly loaded due to less roll in the car.

Dave at trackdevelopments is very good at explaining this with little pictures on his white board and some numbers on an excel spreadsheet.

Rear ARB's are a lot more sensitive so be careful.

If you want to have a play I've got a Rob Farley ARB which I'm not using which you could borrow, if you're ever down in Portslade.

Im currently trying to get my indy car one working correctly.

[Pistol]

An anti roll bar transferrs weight from the inside wheel to the outside wheel.