+1
as we have seen from fiesta and works minis they are landing very smooth and progressive.
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Regarding caster angle: Even if the damper is mounted diagonally doesnt mean its got a lot of caster angle.
Its the theoretical line between mounting of the wheel and the top mount that decides this. So you can have the same caster angle on a diagonal damper like Ford and VW, as on a straight up-and-down one like Citroën and Hyundai.
The positive with the diagonal damper is that it allows for longer damper travel, but since its movement is not in line with the theoretical caster angle it will have more friction.
As I have understood it, caster angle is the angle the suspension has relative to the normal of the road and negative is supposed to be when it lean "backward" from the upright (I.e. The upper contact point is behind the lower contact point). I am not an expert either so I might be wrong though.
I see what you mean with the Fabia being a bit special though because the contact point of the suspension is very far towards the back on the upright.
Unless I remember wrong VW will be getting a new body shell as well so the set up on their test mule might not be the final one.
Edit: it looks like I remembered the Fabia R5 wrong. From my memory it had the contact points in front of the upright and the damper going forwards but it seems it was the opposite. Apologies for that.
Aha... Thanks a bunch! I guess that's why skoda has gone down the route of mounting the damper so far back on the upright.
If it is still allowed to have "ball bearing structure" inside the damper like in the old days I can't imagine friction is a big issue on these dampers though.
Basically this what Lunde said ;)
I think that You confuse it a bit. When the lead point (i.e. the point where You cross the road surface by a line connecting upper and lower joints - steering axis) is ahead of the contact point between the wheel and the surface You have a positive castor - when You steer from straight direction You lift the car body and therefore its own weight brings steering back to straight direction. It gives a stabilizing effect to the steering but brings very high forces and it's one of the reasons why rally cars have often problems with power steering.
I don't think any rally car ever had negative castor but maybe I am wrong. I think some circuit cars have zero or close to zero castor but I am not sure.
As Lunde said You can have positive castor with nearly whatever position of damper as You can place the lower joint elsewhere than at the damper axis. That's the case of Fabia R5 with very extraordinary damper position.
@ Lunde: From what I learned about the Fabia R5 damper position the other disadvantages of diagonal settings are very high forces in steering and worse brake cooling (the damper is placed in the air flow) but as You said the main point is the friction (and the steering reliability). I'm curious about 2017 VW car to see if this idea how to get rid of those negative effects gets also in VW or if it is maybe found not that good like it theoretically shall be.
Ah yeah! You are right, my grey cells have started to work again.
Now that you mention it, it makes sense in my head again. Caster angle polarity is relative to the contact patch on the ground of the wheel and nothing else. The angle of the damper itself towards the normal of the road is irrelevant.
so many explanations, words and waste of time... for a 2 min vid
https://www.youtube.com/watch?v=Gh7gWJAvOvs
I didn’t find any pictures of caster layout with the damper in front or rear of the upright so I had to make my own. I hope I got it right.
One thing I begun thinking about when I made the pics is the position of the steering axis relative to the wheel centre. As you can see on the second pic the steering axis doesn’t go true the wheel centre. What kind of affect does this have to the handling (steering axis true wheel centre or not)?
http://i267.photobucket.com/albums/i...psirw41j9b.jpg
http://i267.photobucket.com/albums/i...psu8awhjar.jpg
In my opinion the steering axis must pass the wheel center at least because of fixed driveshaft length.
By the way asphalt Fabia S2000 had by the default approximately 8,5°castor with the angle of damper being roughly guessing 20°.
For Focus WRC02 I found castor 6,5° on gravel and 7,8° on tarmac.