I just bought an '02 FX4 and am trying to understand a few things.

Anyhow I was noting that the both rear shocks are attached to the axle from the back side of the axle. I have also noted that on some other trucks the shock on the passenger side is mounted to the front of the axle instead of the back. The axle mount on the passenger side of my truck has points to mount the shock either on the front or back of the axle.

My question is, what is the reasoning for the different shock mount locations and what are the benifits?

Thanks to those who help educate my ignorant rearend!

Aaron

 

The staggard shock mounting is supposed to help with the ride of the vehicle, if you have noticed, all Chevy's seem to mount their shocks in a staggard position. My L has the shocks mounted this way also, but my '98 4x4 had both shocks on the rear, I dunno whether they did this just to maybe make the back look more symetrical becuase a big vehicle like that made for towing and such isn't built for ride anyways and it doesn't make that big of a differance. Anyone else have any more input, that's all I can think of.

-Kelly

 

The staggered dampers were implemented to address powerhop or axle wrap under acceleration - same basic concept as under-leaf traction bars but less harsh since hydraulic damping is involved rather than mechanical contact. Same reason the high horsepower Lightning dampers are staggered.

 

I don't mean to horn in on your query Aaron99GT but I thought maybe my situation might apply and help us both if anyone can shed anymore light on this.(?)

I just purchased a 2002 F150 4x2 Supercab Lariat with 17" Chrome wheels and BFG Long Trail tires and the "freeway hop" is very bad, maybe to the point of being unsafe, and the shuddering after road bumps is quite prevalent. My rear shocks are both mounted from the rear of the axle. My dealer says there is a TSB to cover this(but no parts yet). Should I also have the passenger side shock moved and/or should it have been in the forward position already? I hear that the Screws, Lightnings and Harleys all come with staggered shocks. Thanks, KOT.

 

My last F-150 was a 1997 4x2 Lariat SuperCab Short box. It too had the same freway "hop". The TSB for that model year was to hang a mass/damper behind the Rear bumper between the frame rails - not an elegant solution, but it did help to some degree. It oscillated out of phase with the bounce frequency and cancelled some of the motion. Staggered dampers have worked in some instances but not in every case of hop - inconclusive. The main benefit is for high - horsepower hop under acceleration (Supercharged Harley truck/SVT Lightning) or with a high ride height (i.e. 4x4 screw).

 

Correct me if I am wrong but I believe it is a traction enhancing feature. When you accelerate from a stop with a rear mounted shock you are pushing upward against the shock. The shock will react in such a fashion as to keep the front end down. With the shock mounted the other way when you accelerate you are pulling downward against the shock. This lifts the front end and transfers weight to the rear wheel and increases its traction.

Regards

Jean Marc Chartier

 

Tractive forces act on the contact patch toward the front of the vehicle (forward force is what makes you move). This causes the axle to wind-up in a side view (pinion tips up). Rear mounted dampers both tend to extend or go into rebound during this type of event. The rationale for keeping the front - end down doesn't make sense.

The theory for one forward/one rearward is that you have more control during axle WIND-UP. Whether this is during traction-limited acceleration or freeway hop. In wind-up, one damper will be working compression while the other will be working rebound (i.e. wider range of control/damping). Thus giving more control.

Hope this helps.

 

Thanks for the response fellas.... if anyone else has anything to add. feel free

 

Thanks from me too, Guys! Thanks Aaron99GT for letting me tag along with your thread. Looks like some of this may actually make my truck work better!!!!!!!

 

KEEPONTRUCKIN

No problem....glad you learned too