LR setup 06 Rocket

[cooterbrown#61]

I have an 06 Rocket with 08 updates. The left rear currently has a stacked spring setup with a 400 and 175 spring. Is this a thing of the past or are teams still using this setup? I'm used to having a single 200-250 spring on the left rear. So this is new to me to understand what it's purpose is for. Also the car has a short bent lower left rear bar. Is this type of lower bar used for quicker reaction to get up on the bars? Any input would be appreciated Thanks.

[Matt49]

Stacked spring: first we need to know if you have any type of lock nut that the slider between the springs could be making contact with during travel of that shock. It's not common on the LR but has been done. If that's what you have, it's a little more complicated. If it is just a 400 on top of a 175 then you have a 122 pound spring rate. That's pretty soft but not unheard of. The reason they did this instead of just running a typical 14" 125 pound spring is that a single spring that long and that soft will tend to bow in the middle and rub/interfere with the shock. This setups is NOT a thing of the past. 400 with a 200 can be found on many winning cars.
The bent lower left rear bar is to keep it from hitting the birdcage when the LR is at full drop. The car doesn't know that it is bent so it has no affect on handling other than it keeps it from binding where it may have if it were straight. The car doesn't know the bar is bent. Force is applied in a straight line between the endpoints of the bar. The same concept applies to the j-bar. The only reason it's bent is to clear the drive shaft.

[cooterbrown#61]

Thanks Matt49. The spring setup is a 175 with a short 400 with a spring rubber between the 2, and they are hose clamped together. It Keeps the left rear super jacked up and also it gives the car about 275lbs bite. I'm curious to know if this type setup would work good on a low traction sandy surface. Seems like it would with that much bite.

[rakracing]

i've used the stack spring on the lr a lot, biggest advantage I found was because the package has to be preloaded to get your bite setting, when its hiked up on exit its still has spring pressure on lr tire and not just on the bars, always felt it was better on the slick and on rough surfaces, also used it with the lock nut set up.

[Matt49]

There's definitely something to be said for having the left rear preloaded...but man does it ever make it a pain in the a$s to make bar changes. Throw in a 150PSI shock and you've got your hands full.

[gatorade]

^ truth!!!!!!

[jms22]

I was also told that the LR stacked setup helps the car stay up on the bars through the turn...is this true?

[Matt49]

With a softer spring you have to have more preload in the LR to achieve your desired ride height and wedge numbers. With a stiffer spring you might end up with NO preload which means when the car is on the bars and you lift off the gas, it free falls until it hits the spring. This is considered undesirable. Especially to drivers that already aren't very smooth getting into the corners.

[toloud]

Swift makes a 16" 125 barrel spring some rocket guys are using.

[rakracing]

your right matt we have to jack on the birdcage to change bars on the lr, it also tends to tighten entry because the soft spring rate , use the dual stage setup to help that if you need to loosen entry, worked good on small bullring banked tracks.

[drtrkr244]

We ran a 350/150 dual stage on our 09 Rocket blue. We ran zero gap to keep the car free on entry. That along with a 250 fifth coil gave us awesome drive. However, this worked only on the bottom, if the top came in the car was way too tight.