To Push or Pull in 2014

[Crucial_Xtreme]

Enrique Scalabroni analyzes the suspension geometry from 2013 cars front suspension, both pull & push rod and talks about which is best in 2014.

Part 1


Part 2

[Djeeedjeee]

Sorry for dumb questions, but which teams in 2013 where using push/pull?

EDIT: I meant which teams where using push and which teams were using pull

[stefan_]

Ferrari and McLaren were the only ones that used pullrod in 2013, while the rest used pushrod.

[Lycoming]

Front or rear? Cause not just those two had pullrod rears.

[stefan_]

Front of course, because the videos are about the front.

[SectorOne]

just saw it, love watching the videos with Scalabroni. Just whip up the outline of an F1 car in seconds shows he´s been doing it for a while.

[bianpie]

I might not be the right one to talk about it, but I tend to believe the first drawing of the pull-rod must be wrong. It looks to me a push-rod. Ferrari has the rod inclined the other way around. And with the new regulations, the rod should get even more inclined, so the axial tension load should get smaller (and not bigger) than in 2013.
I'm asking for your opinion, as I'm a beginner...

[marcush.]

Quite intriguing how Scalabroni does not clearly state the pullrod as used by Ferrari and Mclaren does rely almost completely on scrub (track Change )to create any meaningful damper movement in bump but instead says the inclination of wishbones is purely for aero reasons.
indirectly he confirms as much as he outlines how the pullrod loads rocket as you reduce the wishbone downward angling..
I´d think the front pullrod as we have seen it in 2013 is dead now .

[Jersey Tom]

I might not be the right one to talk about it, but I tend to believe the first drawing of the pull-rod must be wrong. It looks to me a push-rod. Ferrari has the rod inclined the other way around. And with the new regulations, the rod should get even more inclined, so the axial tension load should get smaller (and not bigger) than in 2013.
I'm asking for your opinion, as I'm a beginner...

I haven't looked through the rest of the video(s) but the first example there ~40 seconds in is indeed a "pull-rod" topology. Imagine the chassis sitting at a slightly lower ride height and it will be a bit more visually obvious.

With control arm inclination being extreme such things - and the resolution of forces - are at times a bit less intuitively obvious. Hence why I use "pull-rod" a bit loosely. For that matter I'd have to work it out but even how much vertical load the pull rod reacts in that case (of nearly flat to ground with very high control arm inclination). I'd think the only time a pull- or push-rod should be supporting 100% of the vertical load of the car is when the control arms are perfectly parallel to ground.

[bianpie]

I might not be the right one to talk about it, but I tend to believe the first drawing of the pull-rod must be wrong. It looks to me a push-rod. Ferrari has the rod inclined the other way around. And with the new regulations, the rod should get even more inclined, so the axial tension load should get smaller (and not bigger) than in 2013.
I'm asking for your opinion, as I'm a beginner...

I haven't looked through the rest of the video(s) but the first example there ~40 seconds in is indeed a "pull-rod" topology. Imagine the chassis sitting at a slightly lower ride height and it will be a bit more visually obvious.

With control arm inclination being extreme such things - and the resolution of forces - are at times a bit less intuitively obvious. Hence why I use "pull-rod" a bit loosely. For that matter I'd have to work it out but even how much vertical load the pull rod reacts in that case (of nearly flat to ground with very high control arm inclination). I'd think the only time a pull- or push-rod should be supporting 100% of the vertical load of the car is when the control arms are perfectly parallel to ground.

If I look at the inclination of the first pull-rod, I see an angle lower than 90 degrees with the vertical force. Based on my civil engineering background, this should compress the rod, and not pull on it. Both Ferrari and McLaren have a pull-rod making an angle of more than 90 with the vertical force.
The second video with a 2014 specs is correct, again based on my limited knowledge.

[Jersey Tom]

I'd say pullrod topology traditionally means having "that" force member closer to the LCA at the chassis and closer to the UCA at the spindle/upright - reverse for push rod. Traditionally also meaning control arms having "reasonable" inclination.

Beside, the more important bit here is recognizing that those drawings are exaggerated. If you look at a photo of the F138 or F2012 front for example, it's a bit more obvious.

At the extreme control arm angles drawn it gets kind of silly anyway, as I said earlier.. at that point your control arms are probably taking up a good proportion of vertical load - they become the push rod!

[Richard]

In that first image the top arm and rod form a closed triangle. That triangulation carries all the vertical load. The rod is at the bottom so it in tension while the top arm is in compression. Hence this is a pull rod.

The lower arm is not triangulated, hence it only works to control the camber

A push rod would triangulate to the bottom arm. In that case the rod forms the top part of the triangle hence it is in compression.

[Shrieker]

I never could've grasped the subject this well without these vids. Thanks for sharing them !

Quite intriguing how Scalabroni does not clearly state the pullrod as used by Ferrari and Mclaren does rely almost completely on scrub (track Change )to create any meaningful damper movement in bump but instead says the inclination of wishbones is purely for aero reasons.
indirectly he confirms as much as he outlines how the pullrod loads rocket as you reduce the wishbone downward angling..
I´d think the front pullrod as we have seen it in 2013 is dead now .

Add to that not needing to preserve the tyres as much as before. I think then rumors about macca going back to push rod are true after all. I see no reason why Ferrari should not revert back to push rod either.

[DaveW]

Add to that not needing to preserve the tyres as much as before. I think then rumors about macca going back to push rod are true after all. I see no reason why Ferrari should not revert back to push rod either.

I agree with you, but I don't think the decision will have much to with the need to preserve tyres (or, then again, perhaps it does....)

[PlatinumZealot]

There will be less suspension changes during an event this year though due to the max fuel weight of 100kg. We might see Ferrari choosing to live with the hard to adjust nature of the front pull rod, now more than in 2012/2013.