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Author Topic:   Offsets, weights and roll centers.
jammin
Dirt Administrator

Total posts: 3279
posted February 14, 2001 04:34 PM UIN: 16262997
I helped someone on another site with this..does anyone have any questions reguarding this?

I will be glad to help if you do.

jammin

KK17
Dirt Full Roller

Total posts: 75
posted February 14, 2001 05:58 PM
Where exactly do you want the roll center on a gm metric frame. Left or right of cl and how high. If you're in the ball park, is it worth messing with. Are you going to gain any advantage either noticable or not? I've seen many different opinions on it and really haven't made a conclusion for myself. Does tire brand make a difference(hoosier/mccreary).

Thanks.... Erik

jammin
Dirt Administrator

Total posts: 3279
posted February 14, 2001 08:19 PM UIN: 16262997
Basically, it is all preference...any set can work with the right contributors (shock/spring/weight combos). You can raise move your center left to keep it from rolling as much or right to get it to roll more. The lower and higher can do the same. It is all preference and depends on the track/setup your running. There is no set magic number. If you know what it is and do not like what your car is doing, you can always make adjustments to it to help the situation. Manipulation of upper a-arm angles will directly affect the roll center, and also offsets play somewhat of a roll. Engine placement will also affect your roll center as well because of the weight. You must take all these variables into consideration when making adjustments. The easiest way is to drive it, make the changes that suit the driver. You will hardly ever come out of the box exactly right. Especially if your like me and think that you can always go faster.

Tires will affect the roll somewhat depending on how much sidewall and air you carry in them. The american racers as we know are pretty hard, so I think it is safe to say that you definitely have more sponge with hoosier.

Erik, I know this isnt probably the answer your looking for, but all I can say is that if you keep up with the settings your running, if you ever change cars, you will more than likely be in a closer ball park with the new car, that is why note taking is so critical in what we do.

jammin

KK17
Dirt Full Roller

Total posts: 75
posted February 14, 2001 08:45 PM
Thanks for the info Jammin. I was given rollcenter software from Chassis R&D for christmas by my girlfriend(what a woman.lol) I think what you have told me has convinced me to play around with it (rollcenter) more than I have(which was never) to see if I can gain that extra little bit.

Thanks again .... Erik

bbracer17
Dirt Maniac

Total posts: 168
posted February 14, 2001 11:04 PM
Jammin why do you say placement of the engine and sponge of the tires affects roll centers? It my affect how the car rolls over but not roll centers.

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