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Do I need an ARB?
Nitrogeno25 - 17/3/16 at 03:53 PM

My car (Lotus Seven S3 replica) Duratec engined, after lots of suspension tweeks (changing springs, dampers, cross weighting) drives very well to my limited driving skills. The handling is balanced and only have a little understeer on corner exit at WOT, easily controlled by lifting a little the throttle.

Now, every track day I've been to, someone came to tell me why I don't use an ARB at the front. Maybe I can fit one and start again changing springs to balance understeer/oversteer, but is there any advantages?

Cheer!


nick205 - 17/3/16 at 04:23 PM

Personally I think the cars are too light to "need" ARBs. There is also the question of how to mount them securely to the wishbones. However there are kits out there so it can be done.


Ivan - 17/3/16 at 04:52 PM

If the car is handling to your liking don't mess with it. An ARB won't guarentee any more speed through the twisties and will lead to you having to re-sort the suspension.


britishtrident - 17/3/16 at 06:38 PM

You have the car balance best to leave well alone.


daniel mason - 17/3/16 at 06:57 PM

A lot depends on how you like to drive!
When I ran the radical I didn't like having a rear ARB but always ran a front ARB.and had it set stiff.
My Jedi is stiffly sprung up front and has no roll bars at all.and they seem to handle well


bi22le - 17/3/16 at 08:10 PM

This is quite a complex subject and as previously mentioned its how you want YOUR car to handle.

I think the reason that people ask you is because many S3 caterhams have ARB on the front. You may have the cups on the top wishbone ready for one which is why people are asking.


brum_gustavo - 17/3/16 at 10:15 PM

If I am not mistaken, installing an ARB up front will increase understeer. It would only improve handling if your car had excessive oversteer. If you like its handling, and if has slight understeer, there s no point in messing with it.As they say, if it ain't broke, don't fix it! ARBs are good for cars with soft suspensions and excessive body roll. That is why we see it in all street cars.


nick205 - 18/3/16 at 08:58 AM

quote:
Originally posted by brum_gustavo
If I am not mistaken, installing an ARB up front will increase understeer. It would only improve handling if your car had excessive oversteer. If you like its handling, and if has slight understeer, there s no point in messing with it.As they say, if it ain't broke, don't fix it! ARBs are good for cars with soft suspensions and excessive body roll. That is why we see it in all street cars.


True, they're used widely on road cars. My 205 GTIs had them and the bushes needed replacing to keep the front one working properly.


mackei23b - 18/3/16 at 08:59 AM

Yes lots to consider on roll bars...but at the end of the day it's how you want the car to handle / and the weight transfer

I've run front and rear bars on the Caterham (always used the soft bar at the front (there are three options on the Caterham), some of the racers run with the front bar removed. Some also report that the rear bar gives less predicable handling.....so it's all down to personal style.

Lots can be done to fine tune the balance of the car without bars, e.g. camber, tyre pressures, rake, amount of toe and flat floor.

Cheers

Ian


Nitrogeno25 - 18/3/16 at 04:13 PM

quote:
Originally posted by mackei23b
Yes lots to consider on roll bars...but at the end of the day it's how you want the car to handle / and the weight transfer

I've run front and rear bars on the Caterham (always used the soft bar at the front (there are three options on the Caterham), some of the racers run with the front bar removed. Some also report that the rear bar gives less predicable handling.....so it's all down to personal style.

Lots can be done to fine tune the balance of the car without bars, e.g. camber, tyre pressures, rake, amount of toe and flat floor.

Cheers

Ian


Exactly, I'm now going from -1º camber at front to -1.5º and hope to almost solve this little understeer. Will see how it handle.

One thing I forgot mentioning is spring rate which are 350lb front/200lb rear.

Many thanks again and sorry for my not so good English!

Cheers


britishtrident - 18/3/16 at 04:45 PM

Leaving aside roll-reduction.
Nearly every tintop has a front anti-roll bar because it allows the front suspension frequency to be reduced relative to the rear this reduces poropoising as the car cross a bump in the road.
Fiiting rear anti-roll bars while almost universal on FWD cars has to be viewed with caution on rear wheel drive cars as can have a major effects on traction.

The advantage for the home builder or racer is rapid adjustment of the front-rear roll couple distribution without changing spring rates with all the work and re-adjustments that entails or even more involved playing with roll-center heights.

[Edited on 18/3/16 by britishtrident]