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Haynes Roadster - ARB or no ARB ?
FFMan - 4/10/20 at 06:24 PM

I'm just finishing of an MX5 based Haynes Roadster for track days etc, and I am surprised it has not anti-roll bars.

Do people add them for racing or track work or does it work just fine with out ?

If you add them, where do you source them, one from a road car would be too still wouldn't it ?

[Edited on 4/10/20 by FFMan]

snapper - 4/10/20 at 08:07 PM

Usually not needed, road car antiroll bar are usually to stiff and fitting an arb usually means you need to adjust springs and damping then because the front has an arb you may need a rear arb, it can all get a bit complicated and the Haynes setup without are usually very good

ianhurley20 - 4/10/20 at 08:17 PM

Mine really had no need of anti-roll bars - I've been in friends 7's with and without but for all but extreme use none is fine

Bluemoon - 5/10/20 at 10:49 AM

Last thing to fit, get the car setup before considering it...

FFMan - 5/10/20 at 11:05 AM

quote:
Originally posted by Bluemoon
Last thing to fit, get the car setup before considering it...


thanks for the advice all.

I was curious because I also run a historic single seater, and last time out the front ARB link broke, and it lost tons of grip. The historic car is broadly the same as the roadster in suspension design, but I get there are a lot of subtleties that can make a heap of difference.


I'll get it setup and out on track and see where it goes.

procomp - 5/10/20 at 11:34 AM

As has been mentioned unless using car for track only use ARB's are not really needed.
You only really use them for fine tuning the car once all other areas of the setup are sorted. Ie chassis is set to gain best from it. Dampers and springs are a known and setup package. just fitting ARB's without first sorting the other areas is pointless.

Many people just add them to stop excessive roll on a car but never realise that the reason the car has excessive roll is due to dampers having completely the wrong valving this then ends up with overly stiff ARB's to fix a problem that shouldn't be there in first place.
another thing to consider is that when using AARB's you are setting them up to gain best balance with fine tuning for a set of known situations IE a track. If using them on the road you wouldn't really know what conditions the roads are in 20, 100, miles away or if suddenly you would need to reset the ARB'S to suit and re corner-weight the car.

So in truth for road and few track-days NO ARB's needed. for out and out YES they are required to get the last little bit of fine tuning and 10th's of a seconds.

As for selecting materials to make one that's a bit tricky as the biggest things ( once car setup dampers and springs are sorted ) that affects selection of strength is driving styles. And that's where most manufacturers cock it up. They will make one bar to fit the car across the range with no knowledge of the individual driver style. For example even on our own Procomp LA race cars i have 9 different strengths of bar available, that covers different driving styles and even with same driver he will use a different strength bar at different circuits say Silverstone and Cadwell park for instance.

Hope that helps a little. Matt

FFMan - 1/7/22 at 07:35 AM

So we did another track day in the week, and when i look at some of the professional photos shot under hard cornering etc, there is a lot of roll, so going with the opinions stated above, ARB not needed unless really pushing on, i'd say the car would benefit from one - see pic

https://www.dropbox.com/s/jn1y1c0kgppm40l/Temp.png?dl=0

I'm not inclined to increase front springs at this stage as it feels ok at other times and i don't want it to get so stiff it doesn't ride the bumps, even though as a track day car only there shouldn't be many.