STACK vs BUMP !!!!!

[Dirtwizard]

There is some confusion here Bump,Stack,Coilbind are 3 totally different setups.
Not counting the lock-in, lock-out deal

[MasterSbilt_Racer]

There is some confusion here Bump,Stack,Coilbind are 3 totally different setups.
Not counting the lock-in, lock-out deal

If you are ignoring the two-step hardware on a stacked spring, it is really just a soft spring. No sense categorizing it any differently.

[moonshine]

bump and 2 stage

I unload and stay on my bump stop unless the track gets real rough. We don't run the typical bump stop that most people are on, that looks like an accordion. We run asphalt style bumps stacked on top of each other with 2 different rates. It's not harsh at all. The spring we run is just strong enough to get the car from the hauler to the track. If it gets real rough then we'll go to the 2 stage, but to me it's a little tricker than the bump. I know alot of people think they are crutches but I love the way the car turns in with them.

[poppy]

if you have 1 1/2 mesurment from the jam nut to the slider by making that a 1/4 of a inch longer/more 1 3/4 gives you more soft spring, which you would want on dry slick like wise making it 1 1/4 would work well on tacky where you do not need to pin the RF as hard.

[F22 RAPTOR]

If you are ignoring the two-step hardware on a stacked spring, it is really just a soft spring. No sense categorizing it any differently.

Exactly true. Stacked and 2-Step Spring are two different animals. I forget to say it sometimes because thats the only way I see, "Stacked" is 2-Step Spring. I'm definitely in the camp that thinks "bumps" and "coil binding" are crutch's and junk engineering, although coil bind is the absolute worst, no offense intended. I guess in a few years will be discussing whether "welded" or "bolted" in place are the way to go... At least bumps are tiny little rubber springs...

[MasterSbilt_Racer]

Exactly true. Stacked and two step are two different animals. I'm definitely in the camp that thinks "bumps" and "coil binding" are crutch's and junk engineering, although coil bind is the absolute worst, no offense intended. I guess in a few years will be discussing whether "welded" or "bolted" in place are the way to go... At least bumps are tiny little rubber springs...

A coil-bound spring just has too much "give". You really need a high-modulus, high yield material for your stops. I recommed a nickel-based superalloy like Inconel 718.

[PayinDaPurse]

Poppy your inbox is full

Poppy your inbox is full

[Moreland24]

if you have 1 1/2 mesurment from the jam nut to the slider by making that a 1/4 of a inch longer/more 1 3/4 gives you more soft spring, which you would want on dry slick like wise making it 1 1/4 would work well on tacky where you do not need to pin the RF as hard.

So basically when you lower the jam nut to allow the car to roll more when the track slows down, (and assuming since your not worried about the wedge when making this adjustment), you are more focused on this allowing the car to put more weight on the RR to tighten the car (mainly entry and mid corner).

[poppy]

That is correct, and I figured out how to empty my inbox. It is way easer to show someone with all the pieces than to explain it. i also think that the spring package I run in the rear. I like a real soft stacked spring set up in the rear. Along with pinning the front you need to get the weight there in a hurry also.

[MasterSbilt_Racer]

So basically when you lower the jam nut to allow the car to roll more when the track slows down, (and assuming since your not worried about the wedge when making this adjustment), you are more focused on this allowing the car to put more weight on the RR to tighten the car (mainly entry and mid corner).

The wedge won't change when you move the nut he is talking about.

[Moreland24]

Right, not static wedge. Just dynamic wedge, right?

[MasterSbilt_Racer]

Right, not static wedge. Just dynamic wedge, right?

Yes and no. You get on the heavy spring at a different point so somewhere between ride height and fully down on the rf there will be some difference. When the car is on the rf, it should basically be the same.

If total travel is the same, dynamic wedge will be the same at that point.

[cushionbumper]

@poppy, check you pm.
Thanks, CB

[29racin]

so i read the whole thread and now am really confused..... stacked and dual stage ARE 2 different things. stacked with a slider does what? (just gives a really soft rate) correct. Dual stage with a jam nut does what? ( qiuck weight transfer and hold down)correct? What are the best rate for the dual stage set-up and do i want for a gap to the jam nut? If I am incorrect please ellaborate for me... thank for the input.. I run 3/8 dirt. DRY.

[F22 RAPTOR]

so i read the whole thread and now am really confused..... stacked and dual stage ARE 2 different things. stacked with a slider does what? (just gives a really soft rate) correct. Dual stage with a jam nut does what? ( qiuck weight transfer and hold down)correct? What are the best rate for the dual stage set-up and do i want for a gap to the jam nut? If I am incorrect please ellaborate for me... thank for the input.. I run 3/8 dirt. DRY.

Stacked = 2 springs stacked one on top of the other with a slider gives you softer combined rate.

2 Step Spring = Same as "Stacked" only you have a jam nut that halts the travel of the slider at a set point of travel and thus changes from combined softer rate to what ever heavy rate spring you are running in the stack.

So running the 2 Step Spring lets you have your body roll on the RF of a light weight spring, which gives you less dynamic cross and increased side bite. However when you throttle up and push over on the RF harder the heavy spring engages and gives you more dynamic cross/bite to drive off corner. Can be best of both worlds if you hit it right, in theory.

We use to use the 2 Step Spring setup, back in the days before the hook setups, to help lift the frontend under accel to transfer the weight better to the rear. Now its used to pin the RF instead of just having it lay over and collapse, which gives good side bite on entry, but lacks dynamic cross to accel off. Good luck.