I think my shocks are too short - Here's why

[will e]

I bent the main leaf spring on my non-stock front spring. My front is spring over axle. I left the shock absorber attached to the axle. With the frame on a jack and the driver front tire on the ground I lowered the passenger side of the axle with the U bolts removed. The shock expanded all of the way and the axle had not separated from the spring. I jacked the axle back up a bit and removed the top shock bolt and tried again. The axle and spring separated however, I have about 4" of space between the fully extended shock's mounting hole and the shock mount location on the frame at the point where the separation occurred.

I assume this means my shocks are too short?

[Stuka]

Well, yes. But its not unusual to have the shock limit down travel. In the Wrangler world for instance we do this to keep our coils from falling out. The shock typically won't get damaged by it limiting down travel unless you are doing some high speed stuff. But you are leaving articulation on the table by limiting it.

Another question would be, how is up travel? Does the shock bottom out before you hit the bump stop? This is much more likely to damage the shock as there is typically more force applied to up travel than down travel.

[will e]

What's a good way to check 'up travel'? I still have the stock bump stops so I am pretty sure if something stops up travel it is the shocks. I haven't ever 'felt' a limit wheeling so I may not be hitting it BUT if I allow more down travel I might find that I am going to find the up travel limit on the other side of the axle.

I am going to do some online research for shocks. 4" of down travel is a lot and I have leaf springs so I don't have to worry about popping a coil out. I guess ideally the spring would be the liming factor for travel.

[derf]

Best way to check up travel is to drive to a spot where you can get crossed up to the point where the low tires in the front and back are off the ground. i.e. front driver side and rear passenger side down in a gully. The other two on high ground.

Optionally, you can get one tire up on a high spot while trying to keep the other 3 on flat ground.

Or, if you have access to a fork lift, you can lift up one tire until the others start to come off the ground.

[Stuka]

A tape measure works on flat ground as well. Although because the shock is outboard, there is a bit of difference. But on flat ground, if you have 5" of up travel, but the bump stop is 10" away from the axle, you need to drop your bump stops. Unless you never get flexed out enough for it to be an issue.

[78 Arizona Chief]

If I remember correctly, your front spring bent at the main eye, not the shackle eye. Main eye bends like yours are simply a result of a decent forward movement hit to a tire that is already drooped down. Your springs, just like mine, rely solely on a single leaf to control side to side movement of the axle and the forward to rearward movement too. They are kinda like a control arm, track bar and a spring all built in one thin package. 37" tires with a jeep as heavy as ours, coupled with a shackle forward design places a ton of stress on that spring at the main eye when we hit rocks and/or drop into wash outs, all of which are super common out here. This is one reason why those desert racers that use to run the J-Trucks did a shackle reversal on the front suspension moving the shackle from the front to the rear of the spring.

Back to shock length. For me, my shock length usually results in figuring out first, how much up travel I want to permit with the tires, body and springs taken into consideration. I then set my bumpstop length to stop the axle at the point I choose. Then I figure out what my maximum collapsed length shock can be, ie measure the static ride height upper shock mount to lower shock mount. Subtract the difference of the axle to bumpstop difference to get the shock mount measurement when the axle hits the bumpstop. I subtract 1.5 inches to account for bumpstop compression (squish) and outboard spring shock mount geometry and that gets the maximum length the shock can be fully compressed. I then find the shock that fits that measurement. I just switched to Universal Fox 2.0s and friggin love them.
Kevin

[78 Arizona Chief]

One last thought, our front springs as short as they are, even in a SOA configuration, can't be the thing that limits travel.
Kevin

[will e]

I was thinking the same thing. My shocks are probably just too short, not lacking enough travel. You like the fox's more than the Bilstien?

[will e]

Well, I messed with it a bit more today. I jacked up the driver side but I know I didn't reach 'full compression' on the spring. When I am wheeling I get a bit of rubbing on the fender on the harder stuff but sitting static in the garage it wasn't that close.

So may plan is to put it all back together with the obviously worn Rancho shocks. I am going to put a tie wrap around each of the shafts on the shocks and take it out wheeling. I will try to compress each side as much as I can. The tie wrap should show me how much compression I have left on the shock.

I suppose one option is to have some custom shock mounts made that will allow for a longer overall shock than stock. There is about 5" of extra room above the stock mount. About 4" of extra length would do the trick and then I could use 14" travel shocks.

[78 Arizona Chief]

I think I would start with bumpstops first. If you are still running the stock short rubber bumpstops, they are too short for your application. Even with the SOA spring packs and u-bolt plate on top of the axle tube, the bumpstops still need to be lengthened to properly prevent not only the tire from contacting the body, but from overly back arching the spring packs too. I run the longest Daystar ones, something like 4.5-5" tall. With those, I think I am running 14" travel front shocks. They are really long. I will see if I can find the part numbers I am running for the bumpstops and the shocks for ya. If you want to cruise by and check out my setup, let me know.
Kevin