Beginner’s guide to F1 suspension

[andrew]

Found this produced by Renault. Thought it would be good to share for any beginners.

How have F1 suspension systems evolved over the years?

The challenge of suspension has been broadly constant for the last twenty years. Ever since aerodynamics became an essential part of F1 design, the challenge has been to produce a system that can support the aerodynamic platform of the car (i.e. allow the car to generate downforce) and yet also allow it to pass smoothly over the bumps and undulations on the ground. Those two things are pulling in almost diametrically opposite directions and so the design of F1 suspension is an extremely tricky compromise.

What material is suspension made from?

It depends what part of the suspension you are referring to because it’s a big and complicated system. However, the most visible parts, such as the wishbones that fix the wheel to the car, are made from carbon fibre. In the past they were made from steel, but around 15 or 16 years ago they started being made from carbon fibre. The inboard parts of the suspension, such as the springs and dampers, which are underneath the bodywork, are made from various materials including steel, aluminium, titanium, rubber and all sorts of stuff.

What is the lifecycle of a suspension system?

It varies from team to team, but if we think of the suspension as the whole corner of the car, such as the front tight, we would expect each corner to last for two race weekends before it came off to be serviced. When it does come off the car, it is sent back to the factory, stripped down, proof-load checked and so on. The underlying structural parts of the suspension will probably last around half a season, providing they are serviced in this way after every couple of races

What is the simplest way of thinking about suspension?

What we’re trying to do is create a suspension that supports the aerodynamic platform of the car and minimises the disturbances caused by the bumps on the road. By minimise we mean keeping the variation of force between the tyre and the ground to a minimum.

A nice analogy is to think of yourself hanging off the side of a cliff by your fingernails. In such a situation you could just about support your own bodyweight and maybe even the weight of a baby on your back. But if the baby started bouncing up and down, it would soon tear you off the cliff face. It’s a similar situation when an F1 car is cornering because the tyre is only just hanging on to the road, and if there is a variation of force (like the bouncing baby) it will tear the car off the surface of the road. That’s why the design of the suspension is aimed at keeping that force variation to a minimum to keep the car fixed to the racetrack.

[Belatti]

What material is suspension made from?

It depends what part of the suspension you are referring to because it’s a big and complicated system. However, the most visible parts, such as the wishbones that fix the wheel to the car, are made from carbon fibre. In the past they were made from steel, but around 15 or 16 years ago they started being made from carbon fibre.

I recall Bruno Senna saying that at the begining of the season the HRT car had steel wishbones...

[colmmonaghan]

Why ever did the teams stop using Torsion bar suspension set-up? BAR Honda used to use them (they were one team that used them. i think.) but you dont here about them anymore?

[DaveW]

Why ever did the teams stop using Torsion bar suspension set-up?

I think (straight) torsion springs are still used. Most use up to 4 springs/axle (2 "corner" springs, 1 "heave" spring & 1 arb). The "corner" springs, where used, are likely to be straight torsion bars.

Don't forget that coil springs are also torsion bars....

[munks]

Don't forget that coil springs are also torsion bars....

I certainly won't forget since I didn't even realize that before.

I'm trying to picture this in my head ... in what way is it a torsion bar? Does the coil spring twist along its length?

[DaveW]

... in what way is it a torsion bar? Does the coil spring twist along its length?

Here is an extract from http://en.wikipedia.org/wiki/Spring_(device):

"Coil spring or helical spring – a spring (made by winding a wire around a cylinder) and the conical spring – these are types of torsion spring, because the wire itself is twisted when the spring is compressed or stretched."

[Giblet]

Here is an extract on how to set up a Williams FW31 from iRacing. Considering all the parameters of the car have been fully measured and parts weighed simulate the actual chassis dynamics, so this document actually pertains to real life as well. If you want to setup an F1 car feel the results, there is no better way to do it.

Chassis
For the most part, the FW31 is similar to most other single-seat racecars, but
it does have a number of unique performance features.
Typical for most
racecars, the front
suspension includes
conventional front
corner springs (torsion
bars as apposed to coil
springs), and an anti-roll
bar. However, the
FW31 also includes a
third spring, which we
call a heave rate spring.
This heave spring adds
additional wheel rate
stiffness in vertical
heave or bounce motion
only. Its primary function is to help control the chassis platform in order to
keep consistent aerodynamic performance. High heave rate settings will
result in less ride height change while the car rides over bumps and while
downforce increases as vehicle speed go up versus softer heave rate settings.
The key in adjusting this component is finding the appropriate amount of
stiffness to help aide the aerodynamics while maintaining an adequate
amount of front mechanical grip. At faster tracks the best compromise
might be to use a very stiff heave rate and give up some mechanical grip in
exchange for better aerodynamics control, whereas at much slower tracks
where raw tire grip would take precedence, perhaps less heave rate would be
required. The correct way to set the front heave spring is to choose the rate
and adjust its perch offset until the spring is just slightly preloaded while the
car has no fuel. This will ensure that, as fuel weight burns off, the heave
spring will always be carrying vehicle load rather than 'floating' off of its
perch, thus forcing the corner springs to do extra work to hold up the front of
the car. For the rear suspension no conventional corner springs are used at all. All of
the lateral, or roll motion, is controlled by an anti-roll bar. The rear also
uses a heave rate spring just as the front suspension does. While it doesn’t
share vehicle load with any corner springs, unlike in the front, there need not
be any concern with how much preload it requires. Set the rate and perch
offset to the desired stiffness and height and go!
You will notice on the General tab a few new parameters which are new to
cars in iRacing.
First, the ballast, although available in a number of our advanced oval cars,
is new to our road racing cars. Ballast placement, and correspondingly
calculated nose weight percentage, allows members to shift weight forwards
and back to affect static front and rear corner weights and consequently
mechanical balance in corners. More forward weight percentage will reduce
oversteer/ increase understeer during cornering events. However, it may
reduce the amount of acceleration traction available powering out of a
corner. More rearward percentage will do just the opposite.
For this vehicle we have made available three brake pressure settings in
order for drivers to reduce or increase braking force to their preference.
These settings are scaled to downforce trim level, so the recommended
setting aligns with which downforce trim has been selected.
Finally, in addition to brake pressure the FW31 also has an innovative way
of changing front to rear braking bias percentage with pedal travel.
Typically, at higher speeds more front brake bias would be advantageous to
help decelerate the vehicle; however, as speeds decrease the optimal brake
bias may need to be more rearward. Base, peak and begin bias ramping
parameters allow the driver to set the minimum and maximum front brake
bias, and ramping determines where the minimum value will start to ramp up
towards the peak number. Play around with these settings at different race
tracks and see which settings work best for you. While sitting in neutral in
your pit box you can press the brake pedal and the digital readout will
display the forward brake bias as
determined by how much pedal
displacement is currently present.Dampers and Inerters
As per your average ordinary racecar, the FW31 has dampers for each
corner. Along with them it also has third dampers, or heave dampers, in the
front and the rear as well. These additional shock absorbers, similar to the
additional third springs, only work with vertical heave or bounce motion.
All six dampers are 2-way adjustable, where adjusting compression and
rebound separately is possible.
Other innovative tuning elements featured on the FW31 include front and
rear devices called inerters. These inerters literally add inertial mass to the
un-sprung suspension without actually adding weight to the wheels, thereby
avoiding the pitfalls associated with extra weight. More inertia will reduce
the ride frequency or response time of the suspension just like a heavier
wheel would, and may be beneficial over different types of track surfaces.
In some instances a lot of inerter mass will be beneficial and at other times
no inertial mass will.

[HampusA]

Here is an extract on how to set up a Williams FW31 from iRacing. Considering all the parameters of the car have been fully measured and parts weighed simulate the actual chassis dynamics, so this document actually pertains to real life as well. If you want to setup an F1 car feel the results, there is no better way to do it.

Should be said though that setups in iRacing does not correlate to the real world right now. (if anyone had any plans to join iRacing and make setups)

In August it will be much more realistic. Just tried the new tire model on an Impala B and my god, it´s like driving a real car now without the G-forces.

Anyway, Giblet, i´ve edited my post regarding G-forces, just so you know.

[Jersey Tom]

Should be said though that setups in iRacing does not correlate to the real world right now.

Says who, and why not?

[HampusA]

Should be said though that setups in iRacing does not correlate to the real world right now.

Says who, and why not?

Tire model is really a bunch of numbers put in to make things "feel" right.
Without a proper tire model and also a updated Aero model that will come in August it can really skew the setups.

Some cars have to much slip angle as it is now, the "aliens" as we like to call them sets up their car so that when they flick the car into a corner it sits in the optimal slip angle.

and the fact that with the present tire model we have to much high speed grip and to little low speed grip. Eric Hudec, the guy who is in charge of the aero model and Dave Kaemmer who built the tire model.

for instance, the Riley Daytone Prototype, right now people are driving with less then 50% BB. That alone is unrealistic but also considering that the optimal slip angle "window" is way larger then it should be in real life.

Basically you don´t get punished for keeping a car in the optimal slip angle.
Which in itself is probably 10 times larger then it really should be.
So Aliens adapt quickly and now "drift" the cars around the corners.
This applies to the F1 aswell but obviously in a much narrower window.

what is pretty encouraging is that real life racers, from the Skip Barber to the Supercar V8 race in iRacing.
Even Lewis Hamilton has taken a spin in the game
Shane Van Gisbergen said this to the present tire model:
"It handles nothing compared to the real thing"

Now he´s a tester for the NTM and said this:
" the car has made giant strides in terms of realism, you can now attack curbs etc without it endning in a mandatory spin etc"

Look up Shane on youtube, the kid has some big cojones and knows a thing or two about getting the most out of a V8 Supercar.

[Giblet]

Here is an extract on how to set up a Williams FW31 from iRacing. Considering all the parameters of the car have been fully measured and parts weighed simulate the actual chassis dynamics, so this document actually pertains to real life as well. If you want to setup an F1 car feel the results, there is no better way to do it.

Should be said though that setups in iRacing does not correlate to the real world right now. (if anyone had any plans to join iRacing and make setups)

In August it will be much more realistic. Just tried the new tire model on an Impala B and my god, it´s like driving a real car now without the G-forces.

Anyway, Giblet, i´ve edited my post regarding G-forces, just so you know.

The new tire model is already applied to some of the oval cars? I wasn't aware of that, but other than the Indy 500 event, I am road only so looks like I am waiting.

I'm also 9th in the world in my Skippy division, but that has nothing to do with anything but me bragging about my current limited success from my own sad little world.

As for the current tire model, I am not aware of any better in home racing sims. The parameters of setup will remain the same regardless of tire model. If you put 27PSI in your front tire, and that's 30 when there is heat in them, that will be the same with the new tire model. What you put in, you will still get out as the whole purpose of a sim is to react to inputs with physics that mirror the real world as best they can. This is why you can back to and play "INdy 500: The Simulation" in 1989, and making small setup changes yielded similar results. tire wear, everything was quite well done, but since the graphics were so simple, it was all about the feel. THis was the first time I felt understeer.

iRacing does actually correlate to the real world, better than any other sim right now. When I raced against Scott Speed the other week, and was handily beaten by him in a miata, he did say that there is nothing else even close. You can race completely on feel and not worry about the 'game'. The guy was pretty fired up, and for someone who has raced an F1 car to be impressed and immersed like that was pretty cool. Bobby Labonte, same thing. He was practicing in a Pontiac Solstice around lime rock "To get some road practice before the Rolex 24 this weekend".

[strad]

Don't forget that most of the suspension movement or springing is compression of the tires sidewall.

[gridwalker]

This is why you can back to and play "INdy 500: The Simulation" in 1989, and making small setup changes yielded similar results.

Cripes, I remember that game ... unfortunately, I SUCKED at it no matter how hard I tried

[HampusA]

The new tire model is already applied to some of the oval cars? I wasn't aware of that, but other than the Indy 500 event, I am road only so looks like I am waiting.

I'm also 9th in the world in my Skippy division, but that has nothing to do with anything but me bragging about my current limited success from my own sad little world.

As for the current tire model, I am not aware of any better in home racing sims. The parameters of setup will remain the same regardless of tire model. If you put 27PSI in your front tire, and that's 30 when there is heat in them, that will be the same with the new tire model. What you put in, you will still get out as the whole purpose of a sim is to react to inputs with physics that mirror the real world as best they can. This is why you can back to and play "INdy 500: The Simulation" in 1989, and making small setup changes yielded similar results. tire wear, everything was quite well done, but since the graphics were so simple, it was all about the feel. THis was the first time I felt understeer.

iRacing does actually correlate to the real world, better than any other sim right now. When I raced against Scott Speed the other week, and was handily beaten by him in a miata, he did say that there is nothing else even close. You can race completely on feel and not worry about the 'game'. The guy was pretty fired up, and for someone who has raced an F1 car to be impressed and immersed like that was pretty cool. Bobby Labonte, same thing. He was practicing in a Pontiac Solstice around lime rock "To get some road practice before the Rolex 24 this weekend".

Yes, but only the Impala B car. So if you owned the old one you get the new one for free.
Should also mention that as the car feels totally different, the settings on your wheel might have to be changed to fully exploit the NTM.

I agree to some extent, NKPro is said to have the best tire model right now (not counting the NTM of iracing that haven´t really been released yet for all cars. But from what i´ve driven it´s just astonishing.)

Congratz, PM me your name and maybe we can race some day, let´s bury the war axes and look forward to some hardcore racing.

True about the pressure. But as of now, the only thing calculated was how fast the tire was spinning based on the wheel rim.
Now it´s a very advanced tire model made from scratch, a theoretical tire model if you may.
where they can add in the numbers, size etc. and get a fully working tire in the sim.
Now i don´t know if it takes into consideration what rubber mixture there is which i´m sure is extremely crucial.

iRacing does actually correlate to the real world, better than any other sim right now.

True but since the tire model can´t provide the data needed to be really accurate it will still produce "bad" setups as the fastest setups of iRacing for the Skippy for example involves ALOT of "drifting" to be fast.

No doubt iRacing is the best sim right now but for sure there is a long way to go before we can call it "real life" apart from the obvious G forces of course.

We will soon have a tire model. then it´s time for a brake simulator, a suspension simulator etc.
there are still many things to be done but as you say, it´s the best right now.

[HampusA]

Sorry for the double post but a tip is to drive the old Impala 2009 for a few laps at Road America, then switch to the new Nationwide car with the NTM.

NIGHT AND DAY

and when talking about the trolls (swedish saying)
[youtube]http://www.youtube.com/watch?v=9WUqy7B7 ... r_embedded[/youtube]