The relative benefits of a pull rod suspension

[Jersey Tom]

"that packaging and adjustment of the pull rod is a nightmare"

No, I do not get the picture. If I am the mechanic paid to working on these cars then I do not care what hoops I have to go through to make a my car more competitive. This is all about having the fastest car with the required reliability. There is no requirement to keep the mechanics happy. There could be some time limitations to making some adjustments, but generally I doubt much is done to the suspension in the form of routine adjustments. Most of the setup should be verified on the 7-8 poster before arriving at the track.

I see nothing wrong from the mechanic's point of view with the current designs.

Brian

In some theoretical perfect world, maybe. In reality, no.. and you are missing many of the practical issues of a real race weekend.

For one, having a car that's easy to work on can be a big competitive advantage. Maximizes speed, minimizes error. Additionally, 7-post rigs are but one tool of many for setup development. They are far from the end-all-be-all of setup work.

[Tim.Wright]

From a mechanical point of view I'm pretty sure that pushrod is the best simply because it is more accurate and precise to push than to pull, regardless of anyone who has said the two options are equal.

What is that supposed to mean?

Tim

[xpensive]

Geometrically, you always get a longer spring-travel with a push rod, hence the better precicion.

[hardingfv32]

Why would there be any limitation on the motion ratio (spring-travel?) with pull rod?

Brian

[ringo]

The push rod is proven to take up too much room.
look on Ferrari in monaco.

There is no geometrical issue, as the pull rod has better geometry becuase of the less critical use of space on the floor of the car.

The push rod you can only extend the A arm knucles so much to get better camber change.

We've seen ferrari try this again.


Another sign they wish they had gone the other way.

They'll change, it's a no brainer.
Just like the high nose, the redbull exhuasts, and all the other things the top team has.

[Jersey Tom]

The push rod is proven to take up too much room.
look on Ferrari in monaco.

There is no geometrical issue, as the pull rod has better geometry becuase of the less critical use of space on the floor of the car.

The push rod you can only extend the A arm knucles so much to get better camber change.

We've seen ferrari try this again.


Another sign they wish they had gone the other way.

They'll change, it's a no brainer.
Just like the high nose, the redbull exhuasts, and all the other things the top team has.

Quoting for posterity

[marcush.]

first of all even if it´s called push or pullrod ,we should not forget both concepts will be subject to push and pull forces.
The main difference is that bump force peaks could be potentially higher as bumps from the road are not as easy to predict as those in the rebound effectively the answer coming from the car.

the funny angles present in rear suspension actuation will inevitably lead to vectoring so not all bump forces will arrive at the spring or damper.. a sign of clever use of those forces or simply testament of unimportance of suspension control with springs and dampers,ARBs and Inerters.

[munudeges]

For one, having a car that's easy to work on can be a big competitive advantage. Maximizes speed, minimizes error.

Having a car that is easy to work on is lovely and from a mechanical point of view a push-rod just looks better, but I'm afraid the effect of not disrupting the aerodynamics has a much, much bigger effect. In order to get an aerodynamic advantage teams, and especially Red Bull, are willing to go through as much mechanical pain as it takes.

Ferrari took a push-rod car to its first win of the season with a lot of blood, sweat and tears, new parts and some regulation changes where no one knows how it actually affected them. I don't see it as much of a vindication.....yet. If the position of the diffuser changes in the future then maybe we will see a change in the trend, but I doubt it.

[xpensive]

Now, I think some members account a little too much of Red Bull's success to their rear suspension. Quite obviously, Ferrari with it's famed 700 staff decided to take another route and I think they've done a reasonably good job with it.

The rear suspension is only one of a myriad parameters on an F1 car, don't read too much into it.

[RacingManiac]

The rear suspension is only one of a myriad parameters on an F1 car, don't read too much into it.

I think thats a view long held by some of us, but in the 20+ pages in this thread it is often seen as the holy grail of RBR's success....for one reason or another...

[munudeges]

It's not the only reason for RBR's recent success, and many have made that mistake, but they didn't go through all that obvious pain at the back of their car for the goodness of their health.

It will be interesting to see the effect of the exhaust positioning next year. If a large enough volume of air can't be pulled through at back of most pull-rod cars around the diffuser, as has currently been aided by exhaust gas, then it's possible we might well see some returning to push-rods next year. The pull-rod adventure clearly isn't as simple as many have thought.

[ringo]

It's not the one thing that gives them success.
It's the fact that they maximise everything and leave no stone unturned.
That apporach has to be taken.
And it seems that Ferrari have learned their lesson this year and will go agressive in every aspect for next year.

Setup time seems less important now, as the setup has to made on friday night or saturday morning and left untouched for the rest of the weekend.

The pirellis also make it so that less running happens in practice, so speedy setup work is not critical.

I have also obseved that the pull rod suspensions have special extention tools that allow the mechanic to adjust the suspension from the outside without opening up the car. Can't find a shot of this, but i think redbull use a hand crank similar to the front wing adjusters.

The main argument for me, is if it works better aero wise, why ignore it?
Isn't aero 90% of performance nowadays?

[Ciro Pabón]

Yep, a myriad, X. A plentitude. Lashings. Teemingness. Plenteousness. Mainly in mellanmjölkens land. However, the thread is about the relative benefits of a pull rod suspension.

Now, everything is relative, except the speed of light, which is the base of relativity. Weird, isn't it?

Nonetheless, I still remember the phrase of my first race instructor:

"Kiddos, always remember when you are going at 200 kph that the only thing that allows you to have a resemblance of control in your race car is four patches the size of the palm of your hand. No tyre, no flyer".

So, I have always given suspension tuning a lot more of respect than engine tuning. Unfortunately I like karts, which have no suspension. Darn.

So, again, the speed of light isn't relative, mainly in relativity.

That's why you can tune kart suspensions, I guess.

For example, you can go faster than light, as Alcuberre showed (he was mexican, so... you know how Latinos are: fantastic realists, no "lagom", Xpensive).

On a side note, I prefer to have my rod pushed than to have it pulled. However, I'm no race car (except in my dreams, but they are weird).

ringo, thanx, I did not know that the setup had to be fixed. However, isn't pushrod a way to give you better weight distribution? You know, win some, lose some...

marcush, as always, good point. Could you elaborate a little? I fail to see clearly why rebound should be easier to predict. After all, if you hit a kerb, hasn't the rebound be calculated based on the bump height? I guess you are talking about peak force, anyway.

[xpensive]

...
However, the thread is about the relative benefits of a pull rod suspension.
...

It is indeed Zero, why I dare to voice my humble opinion that the relative benefits of a pull rod suspension in 2011 is less than been speculated.

But unlike younger, bolder and far more knowledgeable members, I'm an old fart and can therefore only think and believe.

[marcush.]

maybe I miss some point here but the front end arrangements pushrod seem to be awkward to work on as well .
You always try to keep apertures as small as possible and everything is hidden behind the steering rack and column and brake reservoirs..

the RedBull arrangement in the rear now looks pretty accessible -not counting the inerter and the ARB buried in the transmission casing but I´m really not sure if that´s any worse then most pushrod layouts.

On the other hand ..not being able to see is not the equivalent of not easy to work on .The main points with blind applications is really the failsafe layout you have to supply and if possible no loose bits like spacers or washers to have to concentrate on ..as those will be the ones dropping somewhere you will not be able to retrieve them but will cause bad damage later on ..But Newey is the guy who learned from crime commited in earlier days methinks...so he must have an eye on stuff like this.
Of course the no loose bits like washers and nuts is a nice to have feature in everything nuts ands bolts...