anti-roll bars... is it true... thicker the better? always?

[slowlysideways]

looking at getting uprated anti roll bar for my 325 trackcar

should i always replace front and back at the same time?

is it always thicker the better? or can too thick be a bad thing?

any advice would be greatly appreciated, thanks alot!



For instance, can get a 24mm, or a 22mm front ARB for Ԛ£84/97 respectively

and a 16mm rear for Ԛ£85 also...

what would you go for?

[Brianmoooore]

Too thick is a bad thing, ultimately locks both sides of the suspension together. Just right is a good thing.
If it's a track car, that's what testing is for.
Varying the roll bars front to back is one way to control oversteer/understeer.

[slowlysideways]

Could always rely on you Brian for a good answer

So do you know what a standard thickness is? of an '87 325i?


So would you recommend 22mm/16mm then?

[Brianmoooore]

No idea on an E30, especially a track one.
Spent four days at Silverstone a few years back with a professional Formula Renault single seater race team, preparing for the GP support race. I learnt an awful lot about testing and setting up suspension in those four days, even though our race engineer was pretty clueless.
Interesting front suspension on that thing. Only one spring and damper, and the "anti roll bar" was a couple of bevelled washers.

[slowlysideways]

lmao fantastic

just to make sure i dont get too much understeer (would sooner plenty of oversteer) i think im going to settle with the 22mm front, and 16mm rear

cheers for your knowledge brian.

also looking up upgrade my shocks, too soft at the moment

[Andy335Touring]

Not sure which kit it is but some are adjustable so you can play around with the balance, might be H+R ?

[orangecurry]

here's some interesting reading supporting the wise words above

http://www.e30zone.net/modules.php?name ... pic&t=6517

BrianMoooore sir - your guruness just gets more guruy

[eamo]

and a 16mm rear for Ԛ£85 also...

what would you go for?

hi boss

where are you getting the 16mm bar from? web link??

thanks

[slowlysideways]

rallynuts.com

happy to helps

[reggid]

bigger sway bars are good if you like cracking the subframe and if you want the rear trailing arm mounts to fall off. The e30 chassis was not meant to accomodate these large bars without somesort of reinforcement to the mounting points WILL crack.

[Avner]

A sure way to know that the bar is too thick is that the inside wheel lifts off the ground.

[M5pilot]

I have yet to see a an E30 with a problem with the subframe, cracking mounts of trailing arm bushes falling out when people have installed H&R Anti rolln bars which are 22mm front and 18mm rear.

The effects of these roll bars have been nothing but positive as tested by many who have been on the track.

Hartge sold the same 22/18mm setup after much testing, H&R test everything before it is released - I think you'll find this combination of adjustable bars to improve the car a huge amount - this is not based on theory, it;s based on practical experience.

Sal

[Jhonno]

how can a roll bar crack a subframe? if it cracks it must have been fatigued before

also i suspect any rear mounts being broken are cause they are knackard

done 1000's of miles in mine now with the roll bars and have had NO problems whatsoever, only a big cheesy grin on my face everytime i throw it into a corner

[slowlysideways]

dan are yours 22/18 HR items?

[Jhonno]

yeah, they are the nuts

[M5pilot]

Dan's are 22/18 H&R items which are also adjustable.

[slowlysideways]

excellent

there are some for sale rallynuts, called "whiteline"... some are adjustable, but some fixed.

the fixed 16mm rear is Ԛ£85
the adjustable 16mm rear is Ԛ£97

[M5pilot]

Whiteline is nice stuff too ...... still havent got round to adding them to the Zone Shop - available by emailing us or calling us.

Sal

[slowlysideways]

In which I'll add to my next PM I'm just about to send you! LOL

[doughboy]

Dan's are 22/18 H&R items which are also adjustable.

Can someone explain how an arb can be adjustable??

Thanks.

[E30_PWR]

Noone has suggested Eibach ARB kit...they are great and good value for money

[Jhonno]

H&R is cheaper and better..

They are adjustable by having holes at different points therefore varying leverage point

[reggid]

I have yet to see a an E30 with a problem with the subframe, cracking mounts of trailing arm bushes falling out when people have installed H&R Anti rolln bars which are 22mm front and 18mm rear.

The effects of these roll bars have been nothing but positive as tested by many who have been on the track.

Hartge sold the same 22/18mm setup after much testing, H&R test everything before it is released - I think you'll find this combination of adjustable bars to improve the car a huge amount - this is not based on theory, it;s based on practical experience.

Sal

we have lots over failures over here and same in US, particularily where the link mounts to the trailing arm mount. Its nothing more than a cantileverd tab its is a poor design.

We have shocking roads over here to so this could be a factor.

I used a solid 24mm front and solid 16mm adjustale rear (softest setting) and it still oversteered at low speed not to mention that since the car is lowered 30mm the bar link used to hit the body so i'd hate to see what an 18mm rear one would do for balance (unless its a tube type).

[reggid]

how can a roll bar crack a subframe? if it cracks it must have been fatigued before

also i suspect any rear mounts being broken are cause they are knackard

done 1000's of miles in mine now with the roll bars and have had NO problems whatsoever, only a big cheesy grin on my face everytime i throw it into a corner

the rollbar applies variable loads to the its mounting points therefore it can crack the mounting points. So if you make the ARB carry more load by making it stiff it will then it will crack it in less time.

The only load on the rear ARB link point is the ARB load so if its "knackered"its becasue of the ARB. One look at the mount point on the trailing arm and its obvious that its got a limited life with huge ARB upgrades. I think TMS and IE have stiffeners for the mounting points for these problems but i'm not sure on the details of them.

The thing about fatigue is it takes time to occur so because they haven't fallen off doesn't mean they won't. It depends how the car is driven and the condition of the road and the spring rate of the coil springs. Big ARBS on stock springs are destined for failure as they'll do too much work when pushing hard around corners.

When i used my Whiteline 24mm and 16mm ARB it was excellent but at the rear it hit the body when carrying alot of weight people in the back and the car was about 1" lower. Haven't bother sorting out why it was the case so now i have a 22mm front whiteline and stock rear (14mm M-Tech) until i can sort out how to make sure the things won't interfere with the body or fall off then i'll put the 24 and 16 back on.

IMO you don't need much improvemt in the rear but if you do you need alot on the front to ensure its not too oversteery

[E30_PWR]

Cant see how H&R is better than Eibach and not aware of a big price difference...you should get what you pay for afterall...and you take your pick based on your wallet and personal preferance...I would prefer Eibach kit ...comes with front and rear bars and bushes etc..just good quality

[Avner]

Dan's are 22/18 H&R items which are also adjustable.

Can someone explain how an arb can be adjustable??

Thanks.

Usually they have several attachment points (for the links to the susspension arms).
Attaching the links thoward the end of the bar makes the assembly less stiff (more roll).
Attaching the links thoward the center of the bar makes the assembly stiffer (less roll).

[Jhonno]

Cant see how H&R is better than Eibach and not aware of a big price difference...you should get what you pay for afterall...and you take your pick based on your wallet and personal preferance...I would prefer Eibach kit ...comes with front and rear bars and bushes etc..just good quality

so does H&R

[Jhonno]

Reggid - Mine is lowered with the H&R rollbars and never once has the roll bar hit the body and ive been 4 up with fat assed rugby players

[reggid]

Reggid - Mine is lowered with the H&R rollbars and never once has the roll bar hit the body and ive been 4 up with fat assed rugby players

it was the adjustable bar on the softest setting that cuased the problems..........it had too much adjustability .......lol

if i ever go back to using them i think a shorter link will give more travel

[doughboy]

Dan's are 22/18 H&R items which are also adjustable.

Can someone explain how an arb can be adjustable??

Thanks.

Usually they have several attachment points (for the links to the susspension arms).
Attaching the links thoward the end of the bar makes the assembly less stiff (more roll).
Attaching the links thoward the center of the bar makes the assembly stiffer (less roll).

That makes sense, cheers.