pull rod and pushrod how to tell them to apart

[adam2003]

How do you tell them apart, i was looking at the ferrari launch and compared the mclaren car for example, hard to see the difference, any help would be appreciated

[bhall]

Push rods are angled down toward the wheel.



Pull rods are angled up toward the wheel.

[xpensive]

...
Pull rods are angled up toward the wheel.
...

Not so much on a Ferrari.

[superdread]

The name comes from what force is exerted onto the suspension rod when the wheel is pushed upwards.

http://scarbsf1.com/blog1/2010/10/10/re ... odynamics/

Although a bit specific, still some general information and pictures.

[Lycoming]

if the link between the wheel and the springs is loaded in tension in bump, its pullrod. if compression, then its pushrod.

[Steven]

...
Pull rods are angled up toward the wheel.
...

Not so much on a Ferrari.

It still is.

The point is, if you consider the slope of the suspension arms, there is the trackrod connection that is running at a different angle.
- If the trackrod connects from low on the chassis to high on the wheel, it's a pullrod, as it pulls the wheel down on the track
- If the trackrod connects from high on the chassis to low on the wheel, it's a pushrod, as it is pushed into the chassis on bump

[marcush.]

first of all :
pull or push the underlaying aspect of it is clearly :

You use a rod to transmit the vertical wheel force into the chasis .You could mount the sping/damper units directly to the upright or the wishbones ,or have a wishbone doubling up as a rocker as well but Formula 1 has decided decades ago it makes sense to move the springs and dampers away from the airstream between tubenginegearbox and tyre as an aero benefit.
Additionally the rod arrangement will allow you to design rising or falling rate spring and Damper rates by arranging of mounting points of the rockers a very useful thing in the light of aerodownforce rising steeply with speed.
Furthermore you can put favourable leverage on damper or spring movement -very important in the light of miniscule wheel vertical movement....and dampers in need of several mm of travel to build up force!

The downside of it all : starting from the hub your bearing or svivel count is very high ne on the hub one on the rocker ,the rocker itself to the chassis plus the two svivels at each end of the damper ...Inevitably there is a lot of mass but installation stiffness issues as well -as each and every bearing will add to the total give or impreciseness of the system possibly multiplying factors leading to a meriad of other troubles -bind ,slag ,stick slip,vibration -you name it.

The pullrod has a undeniable advantage : the maximum loads will arise always in bump situations and the pullrod is under tension in these conditons -so usually the parts are loaded in a preferable mode-tension when overload conditons may occur. A pushrod will suffer buckling loads in these conditons -so it needs a ALOT more safety margin and therefore needs to be thicker.
The up or downwards angling ios not really a characteristic of the systems to tell them apart .

[superdread]

Could the OP please tell, whether this has helped or if there are particular aspects we should clarify.

Having the 5th independent explanation isn't really necessary.

[xpensive]

...
Pull rods are angled up toward the wheel.
...

Not so much on a Ferrari.

It still is.

The point is, if you consider the slope of the suspension arms, there is the trackrod connection that is running at a different angle.
- If the trackrod connects from low on the chassis to high on the wheel, it's a pullrod, as it pulls the wheel down on the track
- If the trackrod connects from high on the chassis to low on the wheel, it's a pushrod, as it is pushed into the chassis on bump

With all due respect esteemed moderator, I like member superdread's xplanation better:

The name comes from what force is exerted onto the suspension rod when the wheel is pushed upwards.

Brilliant.

[marcush.]

Could the OP please tell, whether this has helped or if there are particular aspects we should clarify.

Having the 5th independent explanation isn't really necessary.

you are right ...your explanation told all that´s necessary -maybe we are just to hungry for TECHN ICAL discussions here ...?

[superdread]

you are right ...your explanation told all that´s necessary -maybe we are just to hungry for TECHN ICAL discussions here ...?

I didn't want to say that any one of the above explanations was the best, or that further discussion or information isn't welcome.

My point was rather, that this topic was made by the OP for a specific reason (understanding pull/push-rod) and if he comes back and sees pages of discussion he won't even bother to read it.
This patience and reticence must have an end eventually, so if he waits too long it's his own fault.

P.S. I'm also all for usurping a topic, ignoring its intend and substituting it for something more interesting. But one likes to appear reasonable from time to time.