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  #1  
Old 06-14-2006, 12:36 AM
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OrlandoAlex OrlandoAlex is offline
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How to fix a stiff/bouncy J10 ride?

Just got a 1978 J10 and working to smooth things out a bit. I took the big mudding nubby tires off and replaced them with some Michelin LTX 31s, still bounces down the road whenever it hits the slightest imperfection in the asphalt. Is this the leafs being set up to handle off-road carnage and heavy lifting? Is it that the shocks are worn out? What's the best way to get this thing to calm down on the road so I don't have to stiffen up my back muscles every time I see a dip? Thanks for your thoughts.
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Old 06-14-2006, 01:07 AM
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BRUTUS BRUTUS is offline
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Mine doesn't have shocks at the moment and it drives just like you state in your post. I would replace the shocks.

I am actually used to it and like it. I cut mine off to do my lift a while back and the next day my roomate told me he was selling the house and leaving the state... UUUUURCH.... was the sound of that plan coming to a complete and final stop!

I especially like it at night when my headlights bounce around ALL OVER THE PLACE... I wonder what the other drivers think?
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Old 06-14-2006, 03:51 AM
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HOOT HOOT is offline
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Is it a stiff bounce you are referring to or a soft bounce

A J10 shouldn't ride real rough unless it has been modified. You have a lift on it? Need more info.

My J20 has the heavy GVWR and rides extremely stiff. I can feel running over an ant. I wouldn't have it any other way
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1980 J20 Utility bed truck. Factory cab and chassis truck. Many new mods for it but it will look all stock.
1985 J10 nothing special just a nice clean stock truck.
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Old 06-14-2006, 05:35 AM
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J10Joe J10Joe is offline
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yeah, i need a lid for my coffee cup in the J10. It's a truck, and rides like one.
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1985 J-10 LWB
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  #5  
Old 06-14-2006, 06:02 AM
Bob Davis '80 Chero
 
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Quote:
Originally Posted by J10Joe
yeah, i need a lid for my coffee cup in the J10. It's a truck, and rides like one.

I learned this the hard way! I have removed two leaves out of the rear spring pack and it has improved the ride to just "rough". Used to jump off the ground after a bump. You may see an improvement with putting some weight in the bed. It is a rough ride and nothing like a GW, IMHO.
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Old 06-14-2006, 06:11 AM
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J10Joe J10Joe is offline
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they are made to carry a load. mine feels 'right' with a face cord of wood in it.
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1985 J-10 LWB
258/727/NP208
4" lift, TFI, MC 2100

1988 J20-one of the last ones
8400 GVRW
360/727/208
TFI, Rustolium (brushed)
Fisher/Meyers plow truck
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  #7  
Old 06-14-2006, 07:37 AM
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OrlandoAlex OrlandoAlex is offline
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It's at stock ride height. The ride is what I'd call stiff bouncy, because it evens out pretty quickly, but for a second or two after the bump, it reacts very strongly. I'm not looking for a luxury ride here, just to keep from getting jarred as much.
Thanks for all of the suggestions so far.
In what's surely a related problem, the seatbelt tensioners seem over-eager, and basically ratchet down a bit tighter every time they get the chance, which is usually when the springs are at maximum compression after coming off a bump in the road. That's when you're squished down in the seat just that fraction of an inch more than usual. Any of you guys ever had that happen?

Last edited by OrlandoAlex : 06-14-2006 at 07:47 AM.
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  #8  
Old 06-14-2006, 07:48 AM
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J10Mike J10Mike is offline
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That's a J10 for ya. The ride wasn't that great before the lift. I did find that the front seemed to get a little less stiff after adding 235 Lbs of new bumper and winch.
Either way, it's still a little rouch on the kidney.
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  #9  
Old 06-14-2006, 08:00 AM
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vstargirl vstargirl is offline
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Dang, and all this time I thought is was the super bouncy bench seat !!!
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  #10  
Old 06-14-2006, 08:15 AM
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J10Mike J10Mike is offline
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Quote:
Originally Posted by vstargirl
Dang, and all this time I thought is was the super bouncy bench seat !!!
If the bench seat in your truck is anything like the bench in my old 67 j2000, that was one bouncy bench...more like a padded trampoline.
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Former - 1982 J10 Sportside, 360, TFI, 727/208, J20 axles, D44HD/Detroit TruTrac, D60/Detroit Locker, D60 disk brake conversion, 4.10s, 5 inch Superlift, 35x12.5x16.5 BFGs on AR767 Wheels. Procomp Super Seats. MileMarker 9000 on Cliffhanger front bumper. Dozer II rear bumper. Rhino Grill conversion. NP208 floor shifter conversion.

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  #11  
Old 06-14-2006, 11:31 AM
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Kali Kali is offline
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I have a 4 inch lift, springs up front, blocks in the rear. The front is noticably more stiff than the rear.

I wish the front wasnt so stiff, speed bumps can get 'physical'

but I also feel the same as J10Joe in that the ride is a lot more smooth with a little weight in the bed, to the point that it becomes very comfortable.
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  #12  
Old 06-14-2006, 12:49 PM
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PlumCrazy PlumCrazy is offline
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Add about 6 or 8 railroad ties...should make it ride a lot nicer

Wayne S
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  #13  
Old 06-14-2006, 01:51 PM
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GW Fisherman GW Fisherman is offline
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Sounds like the same set up and ride in our GW. I think that thing is way to rough. I like the ant analogy. That expains the ride in the GW. I will be watching this thread.
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  #14  
Old 06-14-2006, 02:34 PM
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The PIG Smith The PIG Smith is offline
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Quote:
Originally Posted by HOOT
IMy J20 has the heavy GVWR and rides extremely stiff. I can feel running over an ant. I wouldn't have it any other way

My J20 is a 7600# rig, so a middle of the road as a light duty or a heavy duty J20.
It also rides stiff, like Hoots.
I like to describe it as firm, very firm, but comfortable is a strange sorta way.
I, also, would not have it any other way!
The suspension makes my J20 the truck that is it and is the reason I would never install a lift kit.
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  #15  
Old 06-14-2006, 03:21 PM
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vstargirl vstargirl is offline
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Quote:
Originally Posted by J10Mike
If the bench seat in your truck is anything like the bench in my old 67 j2000, that was one bouncy bench...more like a padded trampoline.

sounds like the one!!
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  #16  
Old 06-14-2006, 06:08 PM
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Allen78J20 Allen78J20 is offline
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my truck is a 8400? gvw and its a stiff ride. There is a reason why they didnt come with cup holders and why I cant have drinks in the truck unless I hold them all of the time! But you put a load in the bed its as smooth as glass. Also if you drive faster over the bumps its rides better. I dont know of any spring vendors that would offer a soft ride spring.
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  #17  
Old 06-14-2006, 07:54 PM
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Herk Herk is offline
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While there is absolutely no reason for these rigs to ride rough, a lot tend to do so. "Firm", or even "stiff" would be typical for the 7000# plus GVWs, but not "bouncy" by any measure. That is, it would be typical to have a fair amount of road feel, and feel small bumps in the pavement. The truck should not flounder over them however. A secondary bounce is a classic symptom of worn out shocks. Unfortunately, any situation where this is noticable, is dangerous.

Now, if you truck has been lifted, there could be some other causes for poor ride quality. A lot of the cheaper lifts just use stiff, low leaf count spring packs. Do they advertize a wheel rate for their springs? Did the vendor ask for your axle weights and desired spring pack camber? Sound like something a custom spring shop might ask? There is a reason for that! But wait it gets worse. What if somebody cheaps out and has the original spring pack "re-arched" to a higher camber? Or even worse, chucks an add-a-leaf or two into a worn out spring pack? Ride will suffer to say the least. When you bend a spring pack into a shape it was never meant to assume, shackle angularity goes out the window! Higher camber spring packs must have a longer main leaf to carry the same weight in the same application. Think about what happens, as the spring compresses, the distance between the spring eyes gets longer. So long as your static shackle angle is vertical or even a bit forward, all is good. The spring flattens and the shackle swings forward. In OEM applications, the shackle angle is usually about right. 15 degrees forward of vertical, and the spring will hit the bump-stop at about 45 degrees. Yeah well duh, right? Lets increase the camber of a stock spring through re-arching. Theoretically, this wont change the wheel rate. But will it? Yep, the rate will go through the roof as soon as the shackle goes past vertical.

Assume a 4000# static (7000# GVW) truck, 60/40 f/r weight dist empty, 40/60 at gross. FAW 2400# empty, 2800# full. Static empty wheel travel of 3 inches empty, 1.5 inch laden; wheel rate will be about 133 lbs/in. Firm, but pretty smooth riding. Lets re-arch them springs up for a 4" lift, giving us a 7 inch travel. If 1 inch of spring compression gave a 5 degree shackle deflection, begining with 15 degrees static, we are now 5 degrees rearward. So, for the first inch of travel we have the 133 in/lb wheel rate PLUS 1200# of truck to force upward to allow the suspension to articulate. Will this make the ride bouncy, harsh or giggly? Oh yeah! Try doing this through an add-a-leaf. Here, we boost the base wheel rate to provide the camber. The ride goes to crap fast, and then things get really ugly once the shackle reverses.

So, lets make that main leaf longer so that we have 15 degrees at the shackle at 4" additional camber. Good, but now when fully compressed we add 35 degrees to the shackles, having them 50 degrees forward. Good enough right? Wrong! Shackles move in an arc, so we may actually overcenter and invert the shackle, locking the suspension into a bottomed out condition. Howz that gonna ride? Longer shackles will be needed with longer main leaf springs.

Will a shock that could effectively dampen a 150# spring cope with a far stiffer one? For a given weight, there will be less linear motion for the shock to do its work in, therefore it must be valved stiffer.

Yes, the above example is a GROSS OVERSIMPFLICATION of what really happens out front of your truck (BSed the numbers too). I assumed static conditions, where loads and forces are equal, giving nice linear relationships. But in the truck, things move! Force=mass*acceleration remember? The numbers get big quick! I also disregarded leaf count on a spring pack, among other things.

So, there is absolutely no single reason why a leafspring vehicle needs to ride poorly. Get a front axle weight, pick a ride height and call a spring shop. It's kinda like playing god! You get to help design exactly what you need. Cost? Call around.

Food for thought,
Nate
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  #18  
Old 06-14-2006, 07:58 PM
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78J10honcho 78J10honcho is offline
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the old girl is just itchin' to do a little work throw a little weight in the back to make her happy.
I would look at the shocks and see how old they look and possibly replace them, but it was never itended to ride smooth,
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  #19  
Old 06-15-2006, 05:49 AM
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This is how I make my J20 drive like a Cadillac....

That is a fully driveable Chero with extra interior and a ton of extra sheet metal crammed in the cargo hold of the Chero. The bed of the truck had 2 doors,3 fenders, a couple of grilles,2 floor jacks,jack stands,100 pound tool bag, 1 spare wheel,misc CJ parts. Made the 5000+ mile trip like it was nothing. DRIVE ON
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Tom Gibson
1980 J20 Utility bed truck. Factory cab and chassis truck. Many new mods for it but it will look all stock.
1985 J10 nothing special just a nice clean stock truck.
1977 Honcho "Blue" 401/400/quad. Under going major upgrades.."This is Not Your Fathers Honcho", it may not even be a Honcho anymore when done.
2017 Challenger. Very jealous of the Jeeps.
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Old 06-15-2006, 07:12 AM
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I'm guessin your in dire need of new shocks. Tequilla has a 4 in suspension lift and definitely rides like a truck.
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