U want the hit to plant the tires and the rebound to hold the tires down longer after the hit to control or slow down the rebound to keep it from unloading , it helps to keep the tires planted after the launch

 

I get that, but either you or I have our settings switched. Rebound is when the shock extends on the hit, compression is what holds it.

 

Compression is on the hit , it happens first

 

Negative. With a radial you want separation from the hit till the end of the run.

 

On the rear shocks compression happens first as the weight transfer compresses the rear shocks on the launch , on the front end the opposite is happening ,the shock is extending and compressing afterwords .

 

This is not correct depending on the anti-squat. Radial suspension setups are going to have a positive anti-squat and will absolutely RAISE on the hit. The shocks extend. A bias slick rear suspension usually has a negative anti-squat number and will lower on the hit.

Also, Viking makes shocks that are valved specifically for a radial setup. However, as of two years ago, their directions were useless for a radial setup.

 

That may be true with bias ply tires, but radials want the opposite,

 

^^^^^Would you elaborate on this please? ^^^^^^^^^^^^^^^^
Provide an example??

 

https://www.racecraft.com/images/REAR-CUSTOM-SHOCK-TUNING-SMALL-TIRE.pdf

 

What do the tire marks look like?

 

I'm far from an expert, but a radial suspension should extend on the launch to plant the tire and use compression to hold it to the track, way to many factors to suggest shock settings, some off the shelf shocks may not even have valving tight enough, if the shock is extending and topping out, will either spin or wheelie if the track is prepped well. Maybe some guys with more experience will chime in,

 

What u are describing is what happens to front shocks , extending on the launch and controlling the compression on the way back down , on the rear it compresses first and tightening the rate of rebound holds the tires to the ground after the rear shock compresses at the hit , U guys seem to be getting confused between front and rear settings , the only way the rear rebounds first and compresses after would be if u are launching in reverse .

 

So my 4 link car with 150% antisquat compresses on the hit?

 

I’m at 115% and with slo mo vids it separates but I’m here to learn why shock settings are suggested opposite what I do.

 

Rear shocks don’t extend on the launch , it has to compress before it rebounds , if this wasn’t the case then u would launch and the back of the car would raise up instead drop first which is impossible and goes against simple physics.Thats like saying if U jump on the rear bumper the shock will extend first before it compresses??

 

Thanks for commenting Honk, something else that helps if you dont have shock sensors is to mount a GoPro under the car, I have one mounted so I see the shocks and the tires. Like he said, no magic formula with all the factors, just have to be be patient and see what the car wants. Not sure what suspension you have but make sure you have the shock travel you need,

 

In Bickels chassis book (at least for slicks) you tighten rebound if the tires are "chattering" on the track. Shocks are allowing the tire to come up, when it needs to be down more (if the track is there/good). Basically, it's the shock saying "fuck you tire, you need to be down". That's the scientific explanation of it.

Treed by Honk.

 

I've got Viking Crusaders on my car, have to keep in mind the recommended setting are just a starting point, the amount of antisquat will have a big affect on the rebound settings from car to car. I've got Vikings sheet in front of me, and I take those suggestions as "weight transfer" settings are to be used if the car has slicks and is set up to squat at the hit. The "front tie down" settings would be a starting point for radials, I'm just starting out with these shocks too so I'm in the same boat. I only got a few passes on 315's but I think I started at 10 compression and 10 rebound as a starting point, which is about in the middle of both.

 

Not after the initial inatant "hit". Still within first 60'.

 

 

Or this could happen.

 

Here is another video, notice how quick the rebound comes into play. Roughly even or just after the stage box.

 

 

The settings I am talking about are for stock type suspensions that squat under power according to Viking tech ,if it separates then the settings are the opposite .

“If the rear suspension is all mounted in the stock location and the rear of the car squats under power then start between 2-6 on compression and 6-12 on rebound.

If you have relocation brackets for your rear suspension and the rear of the car separates under power then start the compression between 6-10 and rebound 2-5.”


After reviewing my setup and watching the videos I sent him He told me 4c-9r for the rear shocks is a good start for my setup on radials (stock g-body).

 

Jesus Christ my head hurts trying to read all of this.

 

Right? Come ask for info, then argue with the guys giving you the correct info...........Uhhhh

 

If the car squats you are pulling load off of the tire for the initial hit. Equal, and opposite, some cars are set up to deal with this.

 

And there's a big difference between a radial slick, and a radial drag tire. We run the radial slicks in Superstock. The radial drag tires are a whole different ball game. We don't run them, so haven't paid any attention to their set ups and characteristics.

 

 

..

 

I run Hoosier radials on my super stock car. Ladder bar set up 600 hp. lots of rear gear. I have single adjustables on the rear. Santhuff shocks on the front My set up is the same with radial or bias tires. The radials are about .13 quicker than bias same size and brand. low 10 or high 9s for ET.3140 lbs. good air, good track prep it will run 1.30 60 ft times. I only run the radials now.

 

Just about the same here. 615 horse, 4 link long bar set up. Lambs on front, Santuffs double adjustable on the back. We don't see .13 back to back against a bias. We used to.... when the gearing was off a little. But since we switched to a 1.54/2.54 gear with a 6200 stall speed the variance dropped down to one tenth ..(3195 weight, 9.60's with 1.26 60ft)

 

The first move in the rear needs to be separation, not squat with a radial. Separate and hold it down.