Rearend shock location - trailing arm setup

[steinepstein]

I understand that shock location is more important on a leaf spring setup but is their any information on a trailing arm or 4-link setup. I see most guys on this site placing their springs in the back, but some aftermarket setups, such as air ride, put them in the front, at least on the trailing arm setups.

Thanks for any input.



Jon

[JRouche]

I understand that shock location is more important on a leaf spring setup but is their any information on a trailing arm or 4-link setup. I see most guys on this site placing their springs in the back, but some aftermarket setups, such as air ride, put them in the front, at least on the trailing arm setups.

Thanks for any input.

Jon

Great question. I think so cause I had the same one when I was building my rear suspension.

I had the room to place them anywhere, I was mounting "coilovers" actually air springs (shockwaves). I saw some shocks mounted behind, in front and even on top of the rear end. So I needed some help. I called a few builders and suppliers to get the scoop.

What I came away with was if the shock is mounted forward of the rear end you have a shock (or coilover) that has more influence with respect to the body roll, road following, and overall suspending. And less with it at the rear. A similar shock will act stiffer at the front than at the rear.

But when its at the rear you gain some adjustability due to the lower leverage. When its on the back its like you have a wider spread of adjustments because you are increasing the distance from the front suspension to the rear suspension.

Ill be honest, I cant explain what Im thinking of. LOL

For example. It you were to place the shocks at the rear bumper (just for visual purposes) they would need to be very strong shocks. But when you make small changes in the valving it also makes small changes in the effect it has on the body or rear end to ground. So there is alot of controlling the effect the shocks, or coilovers have. More detailed adjustments.

And for visual purposes say you mount the shocks, or coilovers three feet in front of the rear end then you will have to use less valving changes because any small change impacts the entire suspension more..

But the key that Im trying to make is with the shock so far forward every lil valve adjustment is gonna have a massive effect on the body. Or rear end to ground which is the proper way of looking at it.

So anyway. Thats why I mounted mine to the rear. To be able to make small changes in shock valving or spring rates and have a linear effect on the suspension. More control with a given input. Not as touchy as if it were mounted ahead of the rear end.

Was I muddy enough in my description?? LOL JR

[steinepstein]

Actually, that was a great description. When you look at it from an extreme it makes a lot more sense, at least for me.

The trailing arm setup I am using locates the air bags in front of the rearend, so I think I will put the shocks behind as to increase valving options and adjustments.

I think air ride chose to place the shocks in front because their kit is for an existing setup that does not require fabrication/welding.

Thanks!

Jon

[marolf101x]

If you are referring to the early C10 trailing arm kits we build the bag/shock placement was for packaging. The stock units are in that location, so we know it'll clear everything.

[David Pozzi]

On a 3 link, 4 link, or truck arm suspension, shocks connected to the rear of the axle will have more travel per inch of axle movement and feel stiffer. Shocks ahead of the axle will have less travel and the springs will be less effective too. It's not a problem to put the springs or shocks ahead of the axle, you just need to compensate for the lower wheel spring rates and shock rates by using a stiffer shock and spring.

Usually it's a packaging thing on where they fit.

On a leaf spring suspension the rear of the car is going to move more on acceleration than ahead of the axle, so a behind the axle location is going to experience more shock movement, a shock is going to have more effective stiffness than ahead of the axle. On regular road bumps it isn't going to be any different front or rear.
David