stack spring

[Matt49]

An important thing to keep in mind is that while we talk about a load at a certain travel, what we really care about is travel at a certain load.
The same goes for shocks. We talk in terms of force at a certain speed but it is more important to understand the speed given a force input.
The force around the corner is what remains a constant for the most part so everything we change on the shocks and springs dictates travel and how fast it gets there, not the other way around.

[Kwhardage]

An important thing to keep in mind is that while we talk about a load at a certain travel, what we really care about is travel at a certain load.
The same goes for shocks. We talk in terms of force at a certain speed but it is more important to understand the speed given a force input.
The force around the corner is what remains a constant for the most part so everything we change on the shocks and springs dictates travel and how fast it gets there, not the other way around.

Been trying to explain that one for a while. Especially getting quoted numbers in the 2600-2800 range for 4" and 4.25". I'm sure somewhere might see that, but the dustbowls around here wont be anywhere close to that.

[Austin34471]

An important thing to keep in mind is that while we talk about a load at a certain travel, what we really care about is travel at a certain load.
The same goes for shocks. We talk in terms of force at a certain speed but it is more important to understand the speed given a force input.
The force around the corner is what remains a constant for the most part so everything we change on the shocks and springs dictates travel and how fast it gets there, not the other way around.

This^

Just because you have a 4,000 lb load number at 4in does NOT mean you are jamming your RF into the ground harder than every other car.

@Twenty-Five, If the car spent the entire lap at 4", then it wouldn't matter. But 4" (in this scenario) is the MAX travel/Load. Most of the way around the track, you are somewhere in between ride height and your maximum.

For example, Lets say ride height load is 800, you travel to 2400, and your nose bottoms out at 4" of RF shock travel.

Option A is a: 400lb/in spring with no bump, which you would have to wind down 2 inches to get your ride height number(800#), then traveling 4" from there would get you to 2400# max load (800 ride height + (400lb spring)x(4in of travel)=2400.)
So your loads would look like:
RH: 800
1": 1200
2": 1600
3": 2000
4" :2400

Option B is a: 150lb/in spring with a 1000lb/in stiff bump spring. You would have to wind it down 8" to get it to hold at ride height. What would happen is, you would have to have this bumpstop shimmed to hit at 3" so that you would hit 2400# at 4". So your loads would look like:
RH: 800
1": 950
2": 1100
3": 1250
---hits bump, add 1000lbs for last inch on top of 150# of primary spring
4": 2400

both options give you the same ride height and max load travels, BUT what happens when you're on corner exit, starting to straighten out, and the track/car setup only provides 1600# of force to the compressing the RF? Where will both of those 2 options be as far as travel? What will that do to your dynamic wedge? What else might it effect?

[billetbirdcage]

This almost exactly the rates Austin used above. Red is the stiffer rate and thus higher 3" numbers but the same basic numbers after 4"




Same car, same night just different RF spring combo's during a private test session

[Drop Shock]

“Anything over 1900 pounds at 4 inches is junk” - Scott Bloomquist

[Austin34471]

"Billetbirdcage on 4m is a genius and he's the reason I am so fast. You should pay attention when he speaks"
- Scott Bloomquist

[billetbirdcage]

"Billetbirdcage on 4m is a genius and he's the reason I am so fast. You should pay attention when he speaks"
- Scott Bloomquist

[fastford]

thats some more tan you got there billet , shame austin caused you to waste that beer.....lol.....

[CCHIEF]

What cars/years you guys in? I'm much softer #'s in a new Rocket

[billetbirdcage]

What cars/years you guys in? I'm much softer #'s in a new Rocket

I may have confused people with me saying rate, I mean that graph was similar spring rates (like 400# spring and 150# spring) that Austin used to show his point. I wasn't meaning actual pound numbers at 1, 2, 3, 4". However the 4.25" where basically the same between the tow, just not the inch numbers Austin listed.

I just overlayed 2 spring rates that was close to what he used to show the difference on track.

[RaceEngineer]

I'd like to thank that guy on Facebook who recommended the Kong dog chew toy for a bumpstop. It really digs! Good jump in rate from 3" to 4"!