roll centers, rear uprights

[Dominik]

What’s a cobra:
Thanks for your input and offer to help!
Serious, Peter used some very old tires frequently for racing, because – well I do not really know. I cannot understand why one would race with old tires J But that was in the 90s. Things have improved.

Anyway, he bought the car (#02) in 1975 and raced it ever since in Europe.
It does handle and all the rest of it, I think he was joking more than beeing serious about the wheel spinning. BTW, he also put a Group-C body on one M8F to compete in Group-C in the 80s.

He ran the M8F before the Hockenheim-Ring was closed down for reconstruction for F1. More a show race, when DTM cars and "what have you" came to run.
Fastest speed that day was Peter’s 203 mph coming out of the forest, second fastest 20 mph less from a DTM. Other drivers asked him if he was crazy... J
We started a Can-Am thread a while ago, but I was batling soo much to access the forum and post pictures that it died away.
I lived in Miami in 1996.

Back to the topic:

Ant,
Plain a-arm length will not result in the same roll centers.
It also depends on where they are mounted in respect to the chassis centerline and wheel centerline. Check my values earlier in this thread.

To calculate roll center always make sure that you find the instaneous center by plotting the lines through the center of the balljoint and chassis mounts. Often the center of a ball joint is 1" or so off the centerline from the a-arm. Get a book or have someone fax you page 36 of Fred Puhn’s book. It’s easier to understand by looking at a picture.

Mick,
yes: we used the center of the anti-dive front upper a-arm as reference.
Same in the rear, where the upper arm is tilted for anti-squat.

For comparison I shall calculate the roll centers of that "handling wonder" which I raced 4 weeks ago and shipped to Europe now.
Front 5.1",
rear – 1" (below ground!) no anti-roll bar in the rear...
No anti-dive or squat.

Dom