What is the Most Important Suspension Component on a Cup Car?

The chassis is suspended - 100% sprung weight.

It does not suspend.
 
I don't know how many teams have a 7-post test system (it applies forces to all four corners and pulls the body down to simulate the forces of a given track), it is a tool that helps teams design or tune the suspension before testing at the track. I think the teams are setting up to minimize the suspension for aerodynamic reasons. (I wonder how minimizing the suspension affects the drivers physically).
 
Zerkfitting said:
I don't know how many teams have a 7-post test system (it applies forces to all four corners and pulls the body down to simulate the forces of a given track), it is a tool that helps teams design or tune the suspension before testing at the track. I think the teams are setting up to minimize the suspension for aerodynamic reasons. (I wonder how minimizing the suspension affects the drivers physically).
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The 7 poster is a dinosaur. 8 is the new 7.

http://www.sovamotion.com/8-post.html

 
dirtfan said:
I'm going to guess it's the anti-dive bars :)
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As opposed to the Dive Bar. :D

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Well if you are considering all componets, mechanical and otherwise, the Driver is your most important.
 
the teams that are winning are using rear steer that are with in the rules,other teams keep trying but they get caught out side of the rules.this is the area that everyone is one is spending alott of time and money. just take my word on this.
 
2 Sweet said:
The truck arms.....more specifically, manipulating the trailing arms in a way that produces more rear steer.
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I would have guessed this would be the answer too, or something even more specific like the truck arm bushings.

Very cool thread. I learn a lot just hearing people who know more than me throwing out their thoughts and guesses.
 
Rear steer, anti-dive, anti-squat and other things are elements of suspension design / geometry and result from the manner in which suspension components such as truck arms and upper / lower control arms are bolted to the chassis.

The question asks which of those and other suspension components is the most important one.
 
Answer this evening when I have time to get into it.

Thanks to all for your interest.
 
They do a pretty good job of manipulating the track bar around to crab walk with the spoiler in or out of the air depending on the track.(rear steer) Track bar comes into play to change the balance front and rear(tight or loose) also. (changes the roll center).
 
aunty dive said:
You understand this stuff. I’ll look forward to your input later on.

I can see that I should have been more specific. A suspension component is something that can be built in-house or purchased from a supplier. Hardware.
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For a single component I'll stick with front end hardware & state its the spindles. Pin height, overall height &
KPI as it relates to ride height, camber curve, front roll center & tire scrub radius. If the steering arms need to be fixed
then Ackerman enters into the equation (toe steer). One item = a lot of stuff going on, get it right & roll the corner.
 
KTMLew01 said:
Roll couple. But if it has to be something you can touch i would say spindles.
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You can apply a formula to calculate front / rear roll couple.

If you do that in writing, you can touch the paper. :D
 
Churchkey said:
For a single component I'll stick with front end hardware & state its the spindles. Pin height, overall height &
KPI as it relates to ride height, camber curve, front roll center & tire scrub radius. If the steering arms need to be fixed
then Ackerman enters into the equation (toe steer). One item = a lot of stuff going on, get it right & roll the corner.
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Great answer. Very important components but not the most important.

It’s been a couple of years but the last time I looked there were more than 50 possible left / right spindle combinations available from the primary supplier.
 
This has been an awesome thread, I know zero about mechanical components of a car. Refreshing to read a thread like this without the arguing we have in other threads and a privilege to hear everyone’s input. I always take great value in learning about something from someone who knows more. Thanks Mr. Dive for starting this thread.
 
Snappy D said:
This has been an awesome thread, I know zero about mechanical components of a car. Refreshing to read a thread like this without the arguing we have in other threads and a privilege to hear everyone’s input. I always take great value in learning about something from someone who knows more. Thanks Mr. Dive for starting this thread.
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Same here. I'm getting an education. Thought I knew some things, found out I know diddly.
 
Snappy D said:
This has been an awesome thread, I know zero about mechanical components of a car. Refreshing to read a thread like this without the arguing we have in other threads and a privilege to hear everyone’s input. I always take great value in learning about something from someone who knows more. Thanks Mr. Dive for starting this thread.
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LOL LOl LOL LOL @aunty dive mr dive... :D
 
TexasRaceLady said:
Same here. I'm getting an education. Thought I knew some things, found out I know diddly.
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Discussions such as this always impress me with how complex suspensions are in the 4-wheel world, compared to the 2-wheel arena that I'm somewhat familiar with. So many more variables with four corners involved. I still think the most important is... the setup and the simulation tools used to arrive at it. But I think Aunty has ruled those are not "components."
 
How about we build a suspension part list?

1. Spring (actually half of spring if calculating "sprung weight")
2. Shocks (same as above)
3. Control arms
4. spindles
5. rear truck arms
6. track bar ( which some confuse as anti-roll bar)
7. hubs (again...for unsprung weight computations)
8. wheels
9. tires
10. ball joints
11. ?

I didn't include any of the steering components as they don't "suspend".
 
KTMLew01 said:
How about we build a suspension part list?

1. Spring (actually half of spring if calculating "sprung weight")
2. Shocks (same as above)
3. Control arms
4. spindles
5. rear truck arms
6. track bar ( which some confuse as anti-roll bar)
7. hubs (again...for unsprung weight computations)
8. wheels
9. tires
10. ball joints
11. ?

I didn't include any of the steering components as they don't "suspend".
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11. Front anti-roll bar.

Unsprung weight calculation includes 100% of the weight of the wheels, tires, front hubs, brake rotors and calipers, front spindles and the weight of the entire rear-end housing assembly from hub to hub including brake components and the third member. Added to all of that is 50% of the weight of the springs themselves and 50% of the weight of all 4 shocks, the upper and lower front control arms, the anti-roll bar connecting links, the steering linkage components, trailing (truck) arms, track bar and the driveshaft.
 
If you’re getting into this, look into a spring’s motion ratio, how it’s calculated and it’s effect on wheel rate.

Wheel rate is at the heart of every calculation, simulation, pull-down rig or shaker rig test, wind tunnel and track test undertaken. The rate of an individual spring (the amount of force required to deflect the spring 1”, expressed in
lbs. / inch) is included in the formula used to determine wheel rate. Mechanical engineer-speak.
 
C3gjV8KUoAE_KDo.jpg


Wheel load transducer. This thing continuously measures dynamic vertical wheel loading (not to be confused with wheel rate) during Goodyear tire / track tests (shared by all teams within each manufacturer’s group). The data derived is the most valuable information available to a race team and is fundamental to computer sims and shaker rig tests.

So ... if you know the tested vertical loading on each of the four corners of the car at a precise point at Bristol (and you do because the tested car’s GPS data runs concurrent with the transducer data) and you’re wondering if a 20 lbs/in increase in the left rear wheel rate would balance the experienced oversteer reported by the driver, make the necessary change(s) and fire up the shaker. Sometimes it runs 2 shifts a day.

It isn’t difficult to understand why on-track testing is severely limited.
 
StandOnIt said:
Nascar didn't insist on anything. When coil bind occurs aprox 4 times the force is exerted on the tire (grip). You and YOUR Toyota's should know this. Why? they used to not have the coil bind setup, they had trick shocks to defeat the ride height rule. Dropped at speed, popped back up when they didn't.
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MY Toyotas do. I didn't. That is why I asked. So, coil bind is in response to 0 ride height?
 
aunty dive said:
C3gjV8KUoAE_KDo.jpg


Wheel load transducer. This thing measures dynamic vertical wheel loading (not to be confused with wheel rate) during Goodyear tire / track tests (shared by all teams within each manufacturer’s group). The data derived is the most valuable information available to a race team and is fundamental to computer sims and shaker rig tests.

So ... if you know the tested vertical loading on each of the four corners of the car at a precise point at Bristol (and you do because the tested car’s GPS data runs concurrent with the transducer data) and you’re wondering if a 20 lbs/in increase in the left rear wheel rate would balance the experienced oversteer reported by the driver, make the necessary change(s) and fire up the shaker. Sometimes it runs 2 shifts a day.

It isn’t difficult to understand why on-track testing is severely limited.
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Aunty, how much would you guess that that car is worth?
 
TexasRaceLady said:
Geez, this sport is getting more hi-tech all the time.
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I love it. Fascinating to me.....and yeah, I loved F1.....and yeah, I suffered through Toyota's attempt at F1....and yeah, I though every week was THE WEEK....but it never was. Brutal.
 
And without the various sensors measuring spring and shock travel, dynamic ride height measurements at 2 or 3 points on both sides of the car, splitter clearance, throttle position, steering angle and a few other things ... all measured dynamically in real time and linked to the data recorded at the wheels and by the GPS system.

All of that is included when the sim or the rig is prepared for use.
 
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