nOOB Question: Do I need 1ton shocks For Rear 1ton Axle swap?

[CDA 455 II]

Baseline:
Rig - '94 Ford Bronco XL 5.0L
Rear axle - '87 Sterling 10.25 dually
Leaf springs - '99.5 F-350 front springs
Lift - Sky ORD 6"
Current rear shocks - Bilstein 24-185530 B8 5100 Shocks
Current cargo weight - Approx 500+lb of stuff


Yesterday I installed OEM upper shock mounts so as to improve shock angle; from approx 45*~50* to approx 90*~.

The axle was moved rearward approx 5" due to said '99.5 F-350 front leaf springs I used on rear swap, hence, the shock angle becoming more shallow.


Issue:
After installing everything I take said Bronco for test drive, going over several dips.

Said Bronco appears to/feels like/sounds like bottoming out at at compress as I drive over dip at speed (35MPH).


Do I need 1ton shocks?

 

[Provience]

you could try "1 ton shocks" but the obvious question is, what are you running for bumpstops? going to a taller rubber bump stop or the OE "xterra" style should help cushion some of that

without going to a tuneable/rebuildable shock it is going to be a world of compromise

 

[total newb]

Where is the shock stroke?
are you nearly bottomed out @ ride hieght?
Are the shocksin the same extended length as previous setup?


You also need to remember how much more the same shock is working at vertical vrs angled.

 

[posford]

How does a shock affect bottoming out? isn't that a result of spring rate?

Your rear springs you spec as 99 F350 front springs. 94 Bronco rear springs have a rating of 1390 or 1650 lbs. 99 F350 front springs have a rating of 2230 to 3950. Are you sure its not just riding like dog shit from running super stiff springs?

 

[CDA 455 II]

you could try "1 ton shocks" but the obvious question is, what are you running for bumpstops? going to a taller rubber bump stop or the OE "xterra" style should help cushion some of that

without going to a tuneable/rebuildable shock it is going to be a world of compromise

Bump stops?


I haven't got that far yet.

 

[CDA 455 II]

How does a shock affect bottoming out? isn't that a result of spring rate?

Your rear springs you spec as 99 F350 front springs. 94 Bronco rear springs have a rating of 1390 or 1650 lbs. 99 F350 front springs have a rating of 2230 to 3950. Are you sure its not just riding like dog shit from running super stiff springs?

It really feels like I'm hitting something; just like I'm bottoming out.


Before I moved the upper shock mounts rearward, I didn't have the bottoming out feel. ZERO.


Excellent point on spring rates.

Since the axle swap I've been experimenting with weight in the bed: zero weight/250lbs/500lbs/750+lbs.

Zero weight feels like the 1ton axle is welded to the frame; no suspension/isolation!

As cargo weight is added; smoother ride is accomplished. AS EXPECTED.

 

[CDA 455 II]

Where is the shock stroke?
are you nearly bottomed out @ ride hieght?
Are the shocksin the same extended length as previous setup?


You also need to remember how much more the same shock is working at vertical vrs angled.

I only measured droop. :rolleyes:

And I only measured from the top of the tire to a point on the quarter panel:
1) Current set up
2) No shocks
3) New set up


I noticed (with axle at full drool with upper shocks mounts not bolted) the bolt-to-bolt mount holes on the shocks matched the distance of the mounting points.

Which leads me to a new nOOB question:
Could my existing shocks be too short?

 

[Provience]

how much shock shaft do you have exposed at ride height?

bumpstops exist to catch the last couple inches of travel and smooth out bottoming. Shocks themselves are just dampers to movement, they simply restrict motion more or less and shouldn't be used as hard stops.

lighter springs, smoother ride as it is more responsive, obviously. put how much weight you Typically have in it, adjust springs to that. add bump stops for the last 2 or 3 inches of travel, drive around and see what you think of it.

 

[CDA 455 II]

how much shock shaft do you have exposed at ride height?

bumpstops exist to catch the last couple inches of travel and smooth out bottoming. Shocks themselves are just dampers to movement, they simply restrict motion more or less and shouldn't be used as hard stops.

lighter springs, smoother ride as it is more responsive, obviously. put how much weight you Typically have in it, adjust springs to that. add bump stops for the last 2 or 3 inches of travel, drive around and see what you think of it.

Approx. 7" shock shaft exposed at ride height.

Mounting point-to-mounting point for the shock at ride height is approx. 23"; yet the shock is listed as 26.16" fully extended.

 

[CDA 455 II]

I noticed (with axle at full drool with upper shocks mounts not bolted) the bolt-to-bolt mount holes on the shocks matched the distance of the mounting points.

Which leads me to a new nOOB question:
Could my existing shocks be too short?

Approx. 7" shock shaft exposed at ride height.

Mounting point-to-mounting point for the shock at ride height is approx. 23"; yet the shock is listed as 26.16" fully extended.

Obvious question is obvious:
Can I safely assume that if the current shocks, fully extended, match the distance of the mounting point while axle is fully drooped; I would need longer shocks?


Strap-limiters appear to be in my future as well; yes?

 

[Provience]

if you aren't doing anything too hard core, you probably don't' need limit straps.

if you are jumping and high flex crawling (forced articulation) and such, then yes straps would help.

 

[Yotota]

Put zip ties on the shock shafts to see how much travel you're actually using, go for a drive, and see if you're actually bottoming out.

 

[Yotota]

Also, post a pic of the new setup. Could be shackle bind or something else mechanical going on.

 

[reptillikus]

Ok im not gonna quote all your posts, but after rereading it a few times, it sounds like youve got shocks that are too short. What is the measurement from the upper shock mount to the lower at ride height? You said 23", and the shock is 26" at full extension, correct?

Since everything has been moved/changed in your suspension, pics of how its all set up would probably help.

 

[CDA 455 II]

Ok im not gonna quote all your posts, but after rereading it a few times, it sounds like youve got shocks that are too short. What is the measurement from the upper shock mount to the lower at ride height? You said 23", and the shock is 26" at full extension, correct?

Since everything has been moved/changed in your suspension, pics of how its all set up would probably help.

I agree.

At full droop (gravity) with shock disconnected; the shock mounts happen to be the same distance as the shock is fully extended: 26".

Since the axle/suspension could/would be able to flex beyond that while on a trail; is the remaining 3" enough for additional flex?


Here's the '99.5 F-350 front leaf spring I'm using in the rear:

Notice the factory bump-stop, and where the 1ton axle will be mounted/installed?

 

[CDA 455 II]

After further inspection; I noticed a shock boot tear, which revealed dents on top of the shock cans.


The shock sits very close to the frame where the factory bump stop sits:

My temporary solution:
I moved the lower shock mount inward -

Looks like mission accomplished:

 

[Provience]

does your shock work better mounted the other way?

that would make a bunch of sense if the body was hitting the frame, that would give you a really shit ride

your factory stop looks about as useless as it could get and going to a longer shock might be better, but then the longer body might also be worse if it won't compress near fully. Basically, measure for your shock at full compression, get as much shock body/travel in there that you can fit, and don't worry about the droop so much.

 

[reptillikus]

Yeah im sure having the shock rub the frame would cause it to ride a little weird!

I agree.

At full droop (gravity) with shock disconnected; the shock mounts happen to be the same distance as the shock is fully extended: 26".

Since the axle/suspension could/would be able to flex beyond that while on a trail; is the remaining 3" enough for additional flex?

Im gonna say no. Under forced articulation, the suspension will travel a couple inches farther than that. Follow Provience's method for setting up the shocks. You might be able to get away with simply moving the lower shock mount, as opposed to replacing the shocks.