science behind adjustable anti roll bar drop links

[StreetDragster]

Hi all,

I'm trying to understand the benefits of using adjustable length anti roll bar drop links.

I have a car that's lowered by 30mm for track use, concensus seems to be that this requires adjustable drop links, but i don't understand why.

The roll bar is free to rotate on its mounts, the standard do links are identical in length on both sides, so surely the bar rotates a little in its mounts to match the new lower arm position when lowered.

What are the implications of the anti roll bar ' tails ' not being horizontal by ~30mm at the tips?

It's £120 plus vat and delivery for four adjustable do links vs £20 for pattern parts all in

Thanks
Matt

[StreetDragster]

Thread resurrection!

At the weekend I had some driving instruction, as part of this the instructor drove both mine and my friends cars back to back and commented that my friends car was much less understeery than mine and that I'm probably driving around this tendency.

This was quite unexpected in the paddock as our cars are very similar in build, except for brands of parts.

Mine -
Mazda RX8
Koni adjustable dampers 50/50 setting front/rear with tein springs
Racing beat anti roll bars front and rear with adjustable drop links
Ad08r tyres
Urethane bushes throughout
Parallel toe front/rear
1.5 negative front camber, 2 rear

His -
Bilstein dampers and springs, none adjustable I think
Whiteline front anti roll bar, standard rear, standard links
Ad08r tyres
Some rubber some urethane bushes
Same settings


I setup my anti roll bars weight on wheels for horizontal anti roll bar with minimal proload.
I now want to adjust them to try and dial our a bit of the understeer.
Firstly, tighten the rear of soften the front?
Secondly, can someone confirm if it's shorter links for softer anti roll bar?

Roll bars are not adjustable in attachment points to the drop links
Track use is hard driving in this case on Anglesey, instructor with us all day so we were pushing it
Both front and rear links are adjustable in length only

Thanks
Matt

Edited by StreetDragster on Saturday 29th April 22:58

[StreetDragster]

Thanks for all replies so far, some research required.

I'm well aware that this may be a complicated issue, race teams don't employ numerous people with college degrees in this stuff because its easy. And I certainly don't have a degree it in either.

However, you have to start learning somewhere and this is the first time I will be trying to change the cars handling with a desired output without 'just' buying parts with a brand name on them.

I have front castor, front and rear toe, front and rear camber, front and rear drop link length, and front and rear damper rebound.

I guess I'm asking, of these adjustable parts, is there any which I could start to adjust to try and dial this understeer out a bit.

Thanks
Matt

[StreetDragster]

Mr2Mike said:

StreetDragster said:

Thread resurrection!

Mine -
Mazda RX8
Koni adjustable dampers 50/50 setting front/rear with tein springs

What are the spring rates like compared to your mate's car? Tein appear to specialise in suspension kits that have all the compliance of a block of steel.

Also is there any difference in the diameter of the front anti-roll bars?

Are you running the same tyre brand and sizes?

Same tyre brands, and sizes on both cars
I'll have to check the anti roll bars and get some specs on the springs

Thanks
Matt

[StreetDragster]

Thanks everyone for the help, really beneficial, especially unhinged.

I'm on Rockingham this weekend, I have taken two psi out of the rear tyres and softened up the front dampers a little, see how it goes, wish me luck.

Thanks
Matt