ARB or no ARB that is the question...
ARB or no ARB that is the question...

Poll: ARB or no ARB that is the question...

Total Members Polled: 12

ARB - You know it makes sense: 83%
No ARB - But watch it at the limit!: 17%
Author
Discussion

Red Cabbage

Original Poster:

3,606 posts

263 months

Friday 22nd August 2008
quotequote all
What's the latest on the rear ARB debate?

Mine is off at the moment and I am debating whether or not to invest in some poly ARB bushes and some Steve Heath drop links before my trip to the 'ring next month.

I've read many of the threads on here but I thought I'd stir up the debate again. smile

Pupp

13,017 posts

303 months

Friday 22nd August 2008
quotequote all
Red Cabbage said:
What's the latest on the rear ARB debate?

Mine is off at the moment and I am debating whether or not to invest in some poly ARB bushes and some Steve Heath drop links before my trip to the 'ring next month.

I've read many of the threads on here but I thought I'd stir up the debate again. smile
No debate as far as I'm concerned. It's propping up the workshop corner and will be staying there smile

Red Cabbage

Original Poster:

3,606 posts

263 months

Friday 22nd August 2008
quotequote all
Pupp said:
Red Cabbage said:
What's the latest on the rear ARB debate?

Mine is off at the moment and I am debating whether or not to invest in some poly ARB bushes and some Steve Heath drop links before my trip to the 'ring next month.

I've read many of the threads on here but I thought I'd stir up the debate again. smile
No debate as far as I'm concerned. It's propping up the workshop corner and will be staying there smile
I should have put money on you being the first to reply. biglaugh

Pupp

13,017 posts

303 months

Friday 22nd August 2008
quotequote all
Red Cabbage said:
Pupp said:
Red Cabbage said:
What's the latest on the rear ARB debate?

Mine is off at the moment and I am debating whether or not to invest in some poly ARB bushes and some Steve Heath drop links before my trip to the 'ring next month.

I've read many of the threads on here but I thought I'd stir up the debate again. smile
No debate as far as I'm concerned. It's propping up the workshop corner and will be staying there smile
I should have put money on you being the first to reply. biglaugh
Aim to please hehe

trackcar

6,453 posts

257 months

Friday 22nd August 2008
quotequote all
If part of a correctly configured kit then no arb is usually the fastest set-up giving better traction out of tight slow corners, however retaining the arb might give the handling characteristics the driver requires .. But even if you keep the arb it's sensible to refrain from making it any more effective than std .. the last thing most TVRs require is more rear roll stiffness unless you're hell bent on creating a drift car .. so the answer as always is yes and no ..

Red Cabbage

Original Poster:

3,606 posts

263 months

Saturday 23rd August 2008
quotequote all
trackcar said:
If part of a correctly configured kit then no arb is usually the fastest set-up giving better traction out of tight slow corners, however retaining the arb might give the handling characteristics the driver requires .. But even if you keep the arb it's sensible to refrain from making it any more effective than std .. the last thing most TVRs require is more rear roll stiffness unless you're hell bent on creating a drift car .. so the answer as always is yes and no ..
Are you suggesting retaining the std ARB bushes and drop links?

shpub

8,507 posts

303 months

Saturday 23rd August 2008
quotequote all
There are three configurations:

1. Standard setup with rear ARB and rubber drop links.

2. No rear ARB

3. ARB with SH drop links.

I've tried them all. Setup 1 as normal makes the car twitchy as the rear ARB applies its correcting force in big dollops. Instead of a gradual progressive correction force, it effectively over compensates.

Setup 2 removes the twitchiness because there is no ARB. However it does let the rear of the car roll more and this in itself does cause problems on the limit. The rear of the car wants to roll more than the front and this can cause some interesting effects when cornering on the limit in terms of stability. What is normally done is to stiffen the rear shocks/springs to compensate for the lack of the ARB. Difficult to do with a standard setup and also a bit frought in getting the balance right as the rear suspension is now stiffer and may be stiffer than the front. This causes issues with weight transfer etc as typically the front needs to be a bit stiffer to compensate. In other words, it really should be done only if the rest of the car suspension is upgraded to compensate.

I have tried it on my Griff and Cerbera. With the Griff, while it was an improvement over the standard setup, it traded one set of problems for another in that the increased roll made it slower through complex corners and roundabouts. It felt like the front and rear were fighting each other. I suspect that the front ARB was trying to compensate for the front and rear at the same time and not doing a good job. On the Cerbera, I have experienced similar characteristics which doesn't give me the same confidence in the car and so the rear ARB is going back on. As I said, with adjustable shocks and changing springs these problems can be addressed but usually at the expence of a stiffer and harsher ride as the suspension is doing the additional job of the ARB.

Setup 3 lets the ARB work progressively. What is interesting is than many people have been able to soften the rear suspension when the SH droplinks have been fitted because the rear shocks/springs no longer need to compensate for the ARB issues. This results in a softer and more complient ride without increasing roll and so on. This does give some indication of the amount of work the ARB actually does in terms of effect. It doesn't change the amount of stiffness on the rear at all because the ARB controls the roll progressively so only the amount of correction needed for the roll is applied. It may seem as if a stiffer rear ARB has been fitted compared to the standard version because the car rolls less. However the ARB stiffness is determined by the ARB dimensions and that has not changed. What has changed is how the correction force is applied. With the standard setup, it is a very coarse application. With the SH droplinks it is progressive. To use a shopping trolley metaphor, one steers the trolley by kicking it from the side and then kicking it from the other side when the trolley turns too much and repeating the operation. The other steers the trolley by applying just enough force to turn it the right amount. One is smooth and the other extremely twitchy.

So what do you do? Personally I wouldn't remove the rear ARB unless it was part of a suspension upgrade where the springs and shocks have been changed to compensate for the missing ARB. It doesn't turn it into a dangerous car for normal restrained driving but it trades the ARB induced twitchyness for increased roll and some peculiar pitching and movement which can be very unpleasant, especially with high speed corners or direction change.

If you do keep the rear ARB, fitting the SH droplinks will remove the twitchyness and make the back end more stable i.e. the suspension works as it was intended to.


Edited by shpub on Saturday 23 August 10:59