Hello from Antony Warmbold

[GigiGalliNo1]

Got it!

http://wrcbehindthestages.blogspot.com.au/?m=1

[dimviii]

Can you post www link again?

link at his signature.

[OldF]

Nice to hear from you again Antony.

It's really hot over here

But not here. After two years of nice and warm summer, this summer hasn’t been so good.

Not knowing what you are going to write about, one issue I can’t recall you have been writing about is the anti-roll bars. I know they’re stiffer on tarmac rallies (as the whole suspension set-up) compared to gravel rallies but what is the relationship to other suspension set-ups (spring stiffness, dampers settings etc.)?

Is the suspension set-up chosen for a tarmac or gravel rally and the anti-roll bars stiffness by the suspension set-up or are they chosen independently (slow and twisty tarmac / gravel rallies compared to fast tarmac / gravel rallies or any combination of these)?

I’ve read some book that by the choose of a stiffness of an anti-roll bar, you can make a choose if the car is more under steered or over steered.

[Antony Warmbold]

Hi, I tried to answer your question on the blog...

WRC behind the stages: An ARB question

See ya

[OldF]

Hi, I tried to answer your question on the blog...

WRC behind the stages: An ARB question

See ya

Thanks Antony,

This clarifies things for me a lot. After I had read your blog I begin to discuss which parts are included in the suspension. I did a little bit googling and the definition varied little. Before I included in the suspension the dampers and the springs but now I would add also the ARBs and my question would have been formulated differently. How do you define suspension?

From the blog:
“The reason for this is I always liked to drive a car "from the rear" if you know what I mean...?”

I must admit I don’t know what it means. Please explain. I don’t have any practical experience of these things, only as we call it “book wisdom” and nowadays also internet.

Juuso Pykälistö once tested few F-group cars and he said that in his mind for most of the cars the suspension was too soft. One of the drivers said because they drive without pace notes in F-Cup, they have better traction when accelerating etc. (vetopito in Finnish) with a soft suspension.

Part of my question:
"I’ve read some book that by the choose of a stiffness of an anti-roll bar, you can make a choose if the car is more under steered or over steered."


From the blog:
”Sure, for example I often ran very soft ARB's on the car to improve the grip on the rear.”

I interpret this that the team had dampers and springs already determined for every rally but the driver could choose the stiffness of ARBs depending on his/her preference of the balance of the car.
Is this correct?

[janvanvurpa]

Thanks Antony,

This clarifies things for me a lot. After I had read your blog I begin to discuss which parts are included in the suspension. I did a little bit googling and the definition varied little. Before I included in the suspension the dampers and the springs but now I would add also the ARBs and my question would have been formulated differently. How do you define suspension?

From the blog:
“The reason for this is I always liked to drive a car "from the rear" if you know what I mean...?”

I must admit I don’t know what it means. Please explain. I don’t have any practical experience of these things, only as we call it “book wisdom” and nowadays also internet.

Juuso Pykälistö once tested few F-group cars and he said that in his mind for most of the cars the suspension was too soft. One of the drivers said because they drive without pace notes in F-Cup, they have better traction when accelerating etc. (vetopito in Finnish) with a soft suspension.

Part of my question:
"I’ve read some book that by the choose of a stiffness of an anti-roll bar, you can make a choose if the car is more under steered or over steered."


From the blog:
”Sure, for example I often ran very soft ARB's on the car to improve the grip on the rear.”

I interpret this that the team had dampers and springs already determined for every rally but the driver could choose the stiffness of ARBs depending on his/her preference of the balance of the car.
Is this correct?

Hej Gammal Finne, if its OK to poke my nose in a little? Ok? Okej since I work on suspension since '75 and manufacure pretty good suspension since 10 years now for mostly gravel rally....
Anti roll bars work by making the car corner flatter but they do that by lifting the INSIDE wheel...Follow with me a bit. You and I, and I'm driving, OK! are approaching a sweeping left corner with nice packed dirt . I initiate the corner and the car leans a bit.. You can say the car leans or another way to look at it is the OUTSIDE wheel on your side goes up....since the rollbar is attached to the arm both sides, as your side, the outside went up, the roll bar wants to "lift" the inside wheel---and that makes the car flatter..
Problem is we are on gravel, and we are flying in my mighty Saab V4 which is front wheel drive... now cornering hard as I do, that inside wheel is already 'light" cause weight has shifted over to the outside wheel..

If its 'light" from dynamic actions, the question is "Do I want to further lighten the load---buy fitting a roll bar that Lifts the wheel?"
Well not if I want any grip, right?
You know from driving ordinary ****-box road cars if you spin the inside wheel---like in the occasional light snow you sometimes may have seen in Finland----they you don't go around corners, you "plow' ahead

So briefly, on gravel the overarching No1 obsession is about grip, and grip we can get and do get by moving weight for example forward with hard braking, then outward with the steeringwheel, and the soft thing for F Cup guys, well most are RWD and there we use TRAVEL, like 230-240mm travel to let us run relative softer wheel rates and that allows the car to squat and still have suspension movement...

So since grip is paramount, anti roll bars which are about piddly fine tuning are of much less important...compared to asphalt where handling is paramount since grip is easy...
I have a pile of Build Sheets for rally Sierra and Sapphires and Escort Cosworth and on all the set up sheets for gravel they all say front and rear "roll bars full soft or disconnected".

This help?

[Antony Warmbold]

Hi OldF, By "driving from the rear" I was trying to say that I liked to come aggressively in corners, make the back slide out (on gravel) and that was making the car turn. I had a lot of grip on the rear from my setup with softer rear springs and ARB's. When I figured that system out it worked well for me, I came faster than before in corners and I had confidence because I knew the car ha a lot of grip and It was not going to be a big slide and I started to have much better stage times.
On tarmac, unfortunately I had the same philosophy at the time, which was wrong. Ironically I learned from Go-karting, later, how to drive efficiently on tarmac.

"I interpret this that the team had dampers and springs already determined for every rally but the driver could choose the stiffness of ARBs depending on his/her preference of the balance of the car.
Is this correct?"

If you wanted you could change everything for your liking. But the car had already a fantastic balance from the 1000's of km that Markko Martin, Francois Duval (and Mark Higgins..?) had determined and it was not necessary to make big changes except tweaking around for your personal style or taste. wether it was dampers, spring, ARB, ride height, etc.

have a good evening

[dimviii]

I know that with the Mini RRC/WRC on testing with Snijers they often changed ARB's, also on shakedown before Ypres last year they tested a few possibilities. They tried 32, 30 and 28mm on the shakedown before Ypres last year, if I remember it right, sometimes changing in front or in back.
@Anthony: Do you know if for example Ø2mm make a real in how the car feels? Did you feel the difference if they changed these rather little things in tests?

at grN evos even 2mm has a lot of difference.Most drivers prefere the medium one(3 choices as well)

[danon]

Just imagine how hyper sensitive one should be in order to sense the 2 mm.
difference right away vs. ambiance, terrain and infinity of circumstances.

May be that's what make the difference between the good, the better and the best.

The best one feel it, the rest - measure it.

[Steve Boyd]

Remember an anti-roll bar acts in torsion so a solid 32 mm bar is nearly 30% stiffer than a 30 mm bar.