Push vs Pull type rear suspensions... which is better?

[ISLAMATRON]

With the adoption of the pull rod suspension for aerodynamic and CoG considerations on the RB5... can anyone comment on what the difference of the two different type suspensions in terms of Traction(& therfore rear tire wear) and rear grip in cornering.

[tomislavp4]

Well, I don´t think that there is any difference in grip between the both. Pullrod gives lower CoG but it´s a real headake for adjusting (sits below everything else in the chassis) pushrod is easy for adjusting but gives high CoG. They both put same force on the wheel assuming you are using same shocks and dumpers....I think

[tk421]

This thread has some info, albeit about the front suspension...

viewtopic.php?f=6&t=740&hilit=pullrod

[Jersey Tom]

No different. Just a question of CG, packaging, adjustability. In theory a pullrod shouldn't be in compression so you should be able to use real light gauge material for it and not have to worry about buckling, but... eh..

[Scania]

so why all team use push rod this years?

[Steven]

so why all team use push rod this years?

Not ALL teams, Red Bull is using a pull rod system, unlike last year when indeed all teams had push rod rear suspensions.

Why they did I think is because of historical reasons. The teams started with it as it was the more conventional and easy adjustable solution. Then, recently sidepods were undercut also at the back, leaving no room for a pull rod type suspension.

With the completely different concepts of this year, I think Red Bull have just found it appropriate to look into it and decided it would be a good solution in combination with their 2009 aerodynamic package. I think this was not really a point of attention in recent years, especially considering that last year teams were busy adding inerters.

[Scania]

but... why no pull rod between Arrows A21 & RB5? Why push rod is so comment?

[Jersey Tom]

It all comes down to a balance of weight, packaging, and performance. It's as simple as.. if the push rod geometry and installation gives a better balance of everything as the pull rod, no reason to go with the latter.

[scarbs]

There’s been a lot of technical discussions on the benefits of push versus pull type suspensions. How the rod is loaded in bump and rebound as well as the loading seen by the outboard end of the wishbone. While the installation stiffness versus weight might vary between the options the main factor is packaging. F1 cars have had front push rod suspensions since the advent of high noses (the Minardi PS01 and Arrows A22 both had a low nose), simply because there was nowhere to package the linkages in a high nose without a poor angle to the pull rod. Pushrods place the parts in a better location for access albeit at a price for Vertical CofG. At the rear the issue has been both a suitable location for the linkages\torsion bars and the third damper (and latterly an inerter), thus atop the gearbox is the ideal solution for a narrow rear end.
This year the need for narrowness is partly negated by the new rules pushing the diffuser 33cm back, leaving space low down to package the linkages etc. However I don’t know how Newey has interconnected the linkages to a third damper and inerter, I guess he has lengthened the gearbox to create space between the engine, clutch and gearbox and passed the two 3rd elements above and below the counter shaft. Access to this lot will be a nightmare, but a sign of true Newey car. Changing torsion bars and dampers will be a floor and gearbox off job.

[Conceptual]

There’s been a lot of technical discussions on the benefits of push versus pull type suspensions. How the rod is loaded in bump and rebound as well as the loading seen by the outboard end of the wishbone. While the installation stiffness versus weight might vary between the options the main factor is packaging. F1 cars have had front push rod suspensions since the advent of high noses (the Minardi PS01 and Arrows A22 both had a low nose), simply because there was nowhere to package the linkages in a high nose without a poor angle to the pull rod. Pushrods place the parts in a better location for access albeit at a price for Vertical CofG. At the rear the issue has been both a suitable location for the linkages\torsion bars and the third damper (and latterly an inerter), thus atop the gearbox is the ideal solution for a narrow rear end.
This year the need for narrowness is partly negated by the new rules pushing the diffuser 33cm back, leaving space low down to package the linkages etc. However I don’t know how Newey has interconnected the linkages to a third damper and inerter, I guess he has lengthened the gearbox to create space between the engine, clutch and gearbox and passed the two 3rd elements above and below the counter shaft. Access to this lot will be a nightmare, but a sign of true Newey car. Changing torsion bars and dampers will be a floor and gearbox off job.

Great Info!

I must ask tho, with the simulation tools available, what are the chances thay they will need to change them on a race weekend? Wouldn't the sim tools get it right the first time anyways?

[Belatti]

Narrow, really narrow!

[Jersey Tom]

There’s been a lot of technical discussions on the benefits of push versus pull type suspensions. How the rod is loaded in bump and rebound as well as the loading seen by the outboard end of the wishbone. While the installation stiffness versus weight might vary between the options the main factor is packaging. F1 cars have had front push rod suspensions since the advent of high noses (the Minardi PS01 and Arrows A22 both had a low nose), simply because there was nowhere to package the linkages in a high nose without a poor angle to the pull rod. Pushrods place the parts in a better location for access albeit at a price for Vertical CofG. At the rear the issue has been both a suitable location for the linkages\torsion bars and the third damper (and latterly an inerter), thus atop the gearbox is the ideal solution for a narrow rear end.
This year the need for narrowness is partly negated by the new rules pushing the diffuser 33cm back, leaving space low down to package the linkages etc. However I don’t know how Newey has interconnected the linkages to a third damper and inerter, I guess he has lengthened the gearbox to create space between the engine, clutch and gearbox and passed the two 3rd elements above and below the counter shaft. Access to this lot will be a nightmare, but a sign of true Newey car. Changing torsion bars and dampers will be a floor and gearbox off job.

Great Info!

I must ask tho, with the simulation tools available, what are the chances thay they will need to change them on a race weekend? Wouldn't the sim tools get it right the first time anyways?

Short answer, no. At least computational. 7-posts are a little better for dynamic rate stuff.

Sim tools are very good at some things, and not so good at others. Even in F1.

You always need room for adjustment, and time is always your enemy.

[kilcoo316]

However I don’t know how Newey has interconnected the linkages to a third damper and inerter,

I guess we're all assuming that the (rear) upper wishbone that joins above the gearbox is a solid hinge with no cross-link?




Going off at a tangent - is there any rule limiting the teams to three springs/dampers per axle?

[ced ampo]

Red bull say that it cleans the [seems to be garbage] rear suspension therefore aiding aerodynamic efficiency. It also helps weight distribution as it is narrower [A WHOLE LOT NARROWER].

[kNt]

A little question on pullrod suspensions:
Why does a pull rod suspension need rods, couldn't they use some kind of strings/wiring (don't know correct term) as the rod is always under tension.