Rear suspension bottoming out on shocks

[ShaveLazer]

This may be a stupid question but my rear suspension keeps bottoming out on my shocks before hitting my bump stops and I am unsure of how to fix it. When I bought my Jeep ~6 months ago it was still on stock rear shocks on a 4 inch lift. To fix that I changed them to FOX 2.0 shocks for 4-6 inch lift (https://www.extremeterrain.com/fox-racing-shox-fox-20-ifp-tj-98024645.html) but now I seem to bottom out on the shock doing tasks that shouldn't bottom it out. Like just going up a curb will often cause the shock to compress fully, with plenty of room before the bump stop would hit. I'm not too smart with bump stops and I didn't put the lift on myself so I'm not sure if they were changed, but by looking at it I feel that the bump stop length needed to prevent the shock from bottoming out first would be like not allowing rear springs to compress at all. So I guess my question comes down to what could the cause of this be, and how long should bump stops be with a 4 inch lift?

 

[Jerry Bransford]

Your shocks are either too long or the bump stops are too short and it's nore likely the shocks are simply too long.

When you have a 4" lift, shocks labeled for 4-6" are usually going to be too long. Best to measure before buying. Having shocks that are too long and then installing taller bump stops to stop the shocks from bottoming out would cripple the suspension. The fix is most likely swapping in shorter shocks that are correctly sized for the amount of up-down travel available in the suspension.

 

[jjvw]

How much shock shaft is exposed at ride height? What is the total shaft length?

 

[ShaveLazer]

At ride height I've got about 3.5 inches of shaft exposed. According to FOX's website the extended length is 24.760" and collapsed is 15.660" for 9.100" of travel. I'm guessing that the length at ride height should be in the middle of that travel length, but when I bought them I guess I didn't know what I was doing.

 

[someguysjeep]

stock mount position up top? any relocation bracket on the bottom?

 

[CodaMan]

... I'm guessing that the length at ride height should be in the middle of that travel length...

Correct! Then set your bump stops to stop them from bottoming out and to stop your tires from hitting anything.

 

[ShaveLazer]

stock mount position up top? any relocation bracket on the bottom?

I am pretty sure the locations are stock, the OEM shocks were still on when I bought it from a previous owner. Also when mounting my new ones on I watched a video to see how to do it and didn't notice any difference in mounting points.

 

[someguysjeep]

you can limit it with more bump to keep off the shock, be where you are now basically. or get the right length shocks and get your inch ^ back, then make an adjustment to the bumps if needed.

 

[jjvw]

At ride height I've got about 3.5 inches of shaft exposed. According to FOX's website the extended length is 24.760" and collapsed is 15.660" for 9.100" of travel. I'm guessing that the length at ride height should be in the middle of that travel length, but when I bought them I guess I didn't know what I was doing.

That's less up travel than stock. And yes, it ought to be closer to 4.5" with that shock. That extra inch would go a long way.

 

[WHBNM]

Rear springs may be a little "tired" too? I run the same shocks with Currie Lj springs (4.5") and have 4.5" of shaft exposed fully loaded with kids and gear. I know.

 

[jjvw]

Rear springs may be a little "tired" too? I run the same shocks with Currie Lj springs (4.5") and have 4.5" of shaft exposed fully loaded with kids and gear. I know.

Measuring the spring will tell us.

 

[ShaveLazer]

Measuring the spring will tell us.

My rear springs are 12"

 

[jjvw]

My rear springs are 12"

If you have a body lift, I wonder if the Teraflex upper shock mount relocation brackets would work with the Foxes. They raise the upper end up an inch if the end if the shock will fit through the crossmember.

 

[k-huevo]

...I wonder if the Teraflex upper shock mount relocation brackets would work with the Foxes...

The Teraflex rear upper shock mount extension is too narrow for Fox, Bilstein, Rancho, and RockSport upper mounts. Also, there is no room for an inverted shock body or dust boot hat to swing. Even if an upper eyelet would fit, and the neck was long enough, the other hurdle is removing the original bushing and bar pin.

 

[Brianj5600]

Where are you in Tennessee?