Rear shackle angle

[roccodart440]

What angle should the rear shackle be in when all the weight is on all 4 tires?

For example, 90 degrees to the frame etc?

Car is street/strip

 

[jefflock]

Bottom tipped back to the rear about 45 degrees if my memory serves me correctly.

 

[68gtxman]

The top of my head says 90 degrees to the frame, as it needs to move equally in both forward and reverse directions. Best to look at the FSM for sure.

 

[805moparkid]

The top of my head says 90 degrees to the frame, as it needs to move equally in both forward and reverse directions. Best to look at the FSM for sure.

no it dosn't as when it comes forward it unloads the tires. Best to have it at a 45* or flatter depending on how rough your roads are. My car seemed to launch best with them at a 30* angle or so but were hitting the frame spacers on bad bumps

 

[roccodart440]

no it dosn't as when it comes forward it unloads the tires. Best to have it at a 45* or flatter depending on how rough your roads are. My car seemed to launch best with them at a 30* angle or so but were hitting the frame spacers on bad bumps

ANd you are talking angled towards the rear correct?

 

[1968FormulaS340]

The important thing is that the bottom of the shackle is more towards the rear than the top.

 

[draginmopars]

this chart is what I set our leaf springs up
Sliders or shackles
.

When at the track- sitting on the line- bring the "R"s up to load the chassis
the car will raise the rear- if set up like the chart
while under load, the shackle will arc sightly forward,

the more angle used will make a different shackle arc , causing the rear of the spring , to move upward toward the chassis,
and the rear of the car to squat and lose some of the cars reaction time

 

[rumblefish360]

Bingo. The last post shows it best. The bottom of the shackle can be even more towards the rear of the car but not to much. Straight up and down (90*) is not good as mentioned above.

 

[roccodart440]

Right, 90 degrees to frame would be over 90 degrees to the spring datum line and they are saying 90 degrees or less to spring datum line.

 

[73Scamp318]

this chart is what I set our leaf springs up
Sliders or shackles
.

When at the track- sitting on the line- bring the "R"s up to load the chassis
the car will raise the rear- if set up like the chart
while under load, the shackle will arc sightly forward,

the more angle used will make a different shackle arc , causing the rear of the spring , to move upward toward the chassis,
and the rear of the car to squat and lose some of the cars reaction time

Out of curiosity, what is the source of this diagram? I don't recall seeing this in the chassis books I have.

 

[roccodart440]

It's from afco (circle track)

http://www.afcoracing.com/tech_pages/leaf.shtml

 

[abodyjoe]