Suspension Bump Stops

[Rockhpr]

Wondering what bump stop options people have used. I have a 86 CJ7 with 4" of lift. I need to add longer bump stops and trying to decide what options I have. I mostly do rock crawling in Moab low speed. Dont know if I want to go to hydraulic or not. I am willing to spend the money if I should. Also wondering about mounting options. I have the ability to weld them onto the frame or drill and tap new bolt holes.
Thanks in advance.

 

[Peanut Butter]

The best solution is to do the fork lift test to determine what you need for a bump stop. Once you have the measurement, you may have to frabricate a base to get the right amount. Poly stop would last longer than rubber.

 

[hole]

Are you having rubbing (or other) issues? What size tires? I'm running a 3" lift on 32's and stock bump stops and have yet to get any rubbing/problems. Heck, I'm strongly considering going 33's next set of tires just to try and start some trouble

 

[Lumpy Grits]

You can lower the stops with square or rectangular steel tubing.
Gary

 

[Rockhpr]

Are you having rubbing (or other) issues? What size tires? I'm running a 3" lift on 32's and stock bump stops and have yet to get any rubbing/problems. Heck, I'm strongly considering going 33's next set of tires just to try and start some trouble

I have a shackle reversal so with full stuff of the wheel it rubs the back of the inner fender. And it has been trimmed back about 1 1/2 inches. I have 35X12.5 15s

 

[hole]

Have no personal experience with 35's, but would a minimal body lift help?

 

[Rockhpr]

Have no personal experience with 35's, but would a minimal body lift help?

I have a 1 in body lift now. I want to keep my body low.

 

[hole]

I think you are going to be making some bump stop extensions . Like PeanutButter suggested, lifting one corner at a time with a forklift will help figure out what point it starts rubbing so you can measure the needed extension.

 

[MattJ]

The best solution is to do the fork lift test to determine what you need for a bump stop. Once you have the measurement, you may have to frabricate a base to get the right amount. Poly stop would last longer than rubber.

Will try this trick on the CJ when we start working on it. Got to finish installing the parts from 4Wheelonline onto the Silverado first before we can clear the garage. Would definitely get poly stop.

 

[TeamRush]

First, I design suspensions for race cars for several years.
Second, we made shocks specifically for applications.
Our shock designs have migrated over into most performance vehicles.
Third, travel limiting (including 'Bump Stops') is MANDATORY.

Compression MUST be Limited on common shocks, both to keep from bending shock piston rods,
And to keep from beating the shock valving on the shock rod end off the shock housing.

While there are all kinds of ideas about where & how to set your stops,
I would recommend about an inch short of full compression for a hard stop.
The 'Fork Lift' method is crude, but it will work, so will a high incline wheel ramp.

Now, this is a corner by corner thing, the shocks are outside leaf springs, so you can't compress the axle as a whole, the angle outside the spring will affect the compression distance with shock outside springs/frame.
So do it one wheel at a time to find your offset distance to keep the shock from over compression.

-----------

While on the subject,
Consider stops (usually straps) to keep the shocks from 'Bottoming Out' at full 'Droop'.
Same deal, the valves on the shock rod are the 'Stop' and can very well be damaged when they hit the other end of the shock tube.

The mall crawlers and daily drivers won't have all the vehicle weight on one wheel, or one wheel dropping in space when the tire leaves the ground...
They won't have these problems unless they hit a parking curb too hard .
Trail mules will do these things SLOWER (less hammering) but the full vehicle weight on compression (loading), and full axle weight on 'Droop' (unloaded) can damage the valve heads, rods, etc.

As a trail guy, I prefer a 'Soggy' suspension...
I use hollow rubber tubes (used on big trucks to soft stop doors),
The rubber tube compresses quite a bit, giving a 'Soft Stop' before the axle hits the actual hard stop inside the tube.
There are some tricky hydraulic and air pressure compression pistons that do the same thing, but the common rubber is cheap and easy to replace when it eventually fails.
I use common carriage bolts for hard stops inside the rubber tubes, again, cheap & effective, but not 'Tacti-Cool'...

One thing about having limiting straps and driving on the highway...
I crank down the straps, compress the spongy springs when I have to highway drive.
This stiffens the suspension, lowers ride height/body clearance when I don't need the clearance, and keeps the vehicle from feeling like it's rolling over in curves & making lane changes.
This also helps keep fat/spongy tires from 'Cat Walking' in pavement lane grooves, etc.
(For those with involuntary lane change problems!)

Commercial ratchet straps are cheap and work well for this purpose.

For those that *Believe* there won't be 'Consumable' parts on a heavy duty off road vehicle...
I've been doing this since birth, 60 years now, from farm equipment, to military vehicles, to civilian off road vehicles...

You have two choices,
Light weight and consumable, which CJ Jeep's were intended to be,
OR,
Heavy metal which presents it's own problems, and costs a load more when it fails (and it WILL eventually fail).

With a load of practical experience,
And having done everything from Duce porthole axles to Dana 30s,
I can say 99.9% of CJ (off road, not off highway) Jeeps would be nearly bullet proof with HD (truck) Dana 44 axles.
(Or if weight is a consideration, Ford 9", particularly if you want rear disk brakes)

We all know about gear to gear transfer cases instead of chains.
It's just more reliable with less maintenance.

With straps, you can SEE, and have easy access to them, inspection & maintenance is VERY simple, replacements are cheap...
And with a ratchet it's easily adjustable and makes the vehicle more versatile/efficient.

Axle travel (bump) stops are another of those stupid simple things you simply add to your maintenance inspection sheet, just have a look, poke them, and done...
A broken or blown out shock is a trip killer, cripples the steering and control, so it makes sense to add stops.
Soft stops are better than hard stops, but either will save your shock...

Soft stops help save wheel bearings, ball joints, and your kidneys from the stop jolt!

It's all in your application, what ever you are doing and want to take on...

 

[73AMC360]

I'm running 35x 22.5 with a 2 1/2" spring lift and 1" body lift on my narrow track . In order to take advantage of my added travel I extended my shock mounts 3". Then purchased longer shocks so I can use my travel.
Put a zip tie or fiber washer on the exposed rod of the shock. Push it down to the shock. This is a great indicator to let you know how much of your travel you are using before you contact the bump stop. If you ever see it at the top of the shock you better make a change.

 

[Rockhpr]

Wow, that's a lot of information to absorb. Thanks

 

[007]

I'll go a step further than the excellent advice given so far...and I learned this from a couple good friends on here...take your shocks OFF and do the forklift work on each corner. This will tell you what shocks to have to begin with. Make sure you have more travel than your chassis will allow... You could very well be riding a shock valve and otherwise not know it. Those of you with a shackle reverse will appreciate this as you'll be a lot closer to where you need to be doing it this way, as this makes it a bit easier to get those front wheels back towards the body when compressed.

Once you have the shocks you need, do it again to measure out your bump stop locations. Again, for those of you with a shackle reverse, it's it bit more tricky so you might want something adjustable. Forklift will get you close but in the event you need to run them out a bit - you can.

 

[Rockhpr]

Thanks, I do have the shackle reversal. One of my favorite upgrades.

 

[gdselzer]

Resurrecting this thread.

I recently put OME springs, 5" shackles, and 33s on my 84 CJ7 (a little over 3" lift from the previous stock setup). No body lift.

I took it out for some rocky but tame wheeling and got a lot of rubbing on the rear. Parked a back tire on a rock in a way that I was maybe a 1/2 inch shy of rubbing. Measured it and there is 7" between the frame and top of axle. That feels like a lot of extension for a bump stop, especially given my relatively mild lift.

First, am I doing something wrong? Short of a body lift, is there any way to reduce the amount of extension I need?

Assuming the answer to my first question is "no", how/where do I go to get a 7" bumpstop? Teamrush, I like your idea of using rubber tubes. Can you point me to what, specifically, you are using?

 

[Patrick]

A lift is just a lift, not an increase of suspension travel. Snubbers must be adjusted by the same amount of lift or springs will compress beyond design specs and bend. This is especially true with today’s cheap products. This is the most overlooked step with suspension lifts so there is no “complete” lift kit. You can reuse your original snubbers by adding a spacer.

 

[gdselzer]

Patrick, thanks for reaffirming my need for bump stop extensions. By my calcs, I need 5" spacers if I reuse my snubbers. Are you able to point me to specific sources or products that get me 5"?

Thanks again

 

[Patrick]

Extending snubbers to amount of lift is just a general guideline. Based on your mild lift, you should be able to safely run about 2.5 inches of snubber relocation. You want to be careful here, excessive spring compression limit adds risk of landing on your haircut, God forbid.

Heavy wall 2.5 inch square tubing is commercially available to fabricate spacers.

 

[gdselzer]

Patrick, I'm confused. The stock bumpstop is 2". So with a 2.5" extension, that will give me a 4.5" extension, right?

As I said, my goal is to keep my tires from hitting the fender. I measured 7" from the bottom of the frame to the top of axle when my tire was ALMOST to the fender. How does a 4.5" bumpstop help? Won't the tires still hit the fender? Or are you suggesting I weld 2 x 2.5" tubing to create a 5" extension?

I was hoping to avoid fabrication (especially involving welding). Are there commercially available or other hacks that don't involve welding?

 

[Patrick]

Ok, let’s simplify. If you can go back and rearticulate your axle where the tire ALMOST rubs against the fender and safely hold it there. This time, measure the gap between the snubber and the axle top. That would be amount of spacing you would need to add sandwiched between your snubber and frame.

This modification is only a remedy to tire rub on your fender. I discourage you from going too big on snubber spacing.

You also have other options like fender wheel well modifications. Or, if you are using fender flares, replacing them with a different variety. JP magazine had an article on a no lift YJ on 40 inch tires, but this of course involves fabrication skills which you might not have or simply don’t want the hassle. There shouldn’t be any welding involved with spacer fabrication. Modify your rig safely all the time. I invite other users to chime in and help you.