Situation....

Long Pedal assault on a loose rock/dirt/slick shit hill. Tires spinning and clawing, 30-45* angle.

Kate is bouncing like a FIEND by the time I crest the top of the hill.

It used to be VERY bad when I was carrying 300lbs of shit in my toolbox located over and to the rear of my axle.

I have since turned up the R9000's to "5" and gotten rid of a lot of weight. I am down to about 75# in my new "in the floor" toolbox.

I have stock FJ-55 springs and I usually run 5-7# in my 42's.

My shocks are in the stock location, not inboarded at the top...they are about 30*

What to do?

Bouncing breaks stuff. Fact.

Do I add another set of shocks? Sup? Ideas wanted...

From what I have been told a lot of the bouncing issues result from the tire loading and unloading. That is why the big boys are stepping up to 17" rims. Try the same hill with a bit more air in the tires and see..

p.s. I am working on the pipe caps..

another set of shocks?? thats my best guess.

i have the 5000's and those are pretty stiff.

let us know what worked when you are done.

I think bouncing can be a side effect of doing the front shackle reversal in combination with the spring over. I've seen this happen after the SR on several trucks including my own. With both set of shackles in the rear, the body can easily lurch up from the axles since the pivot points are in the same angle. When the tires hook up and then lose traction, such as on a steep loose incline or on stairsteps, the suspension cycling begins and continues to multiply until you get off the throttle. My cruiser has literally jumped all four tires off the ground when I didn't back off trying to climb some loose steps. Soft springs, increased axle wrap from the SOA and a heavily loaded cruiser all compound the problem.
I have cranked up the shocks and that helped a little but I didn't like what it did to my ride the rest of the time. In my case the two things that helped the most were lightening the load and easing up on the throttle.

Well the first thing that comes to mind Nolen is a Traction bar.......you have one right? if not then a traction bar is what will keep your tires planted, and squat your rear end down under load and hill climbs. I honestly don't think shocks will do dick for you. Duel shock apps are great for IFS trucks and high speed off-road apps. (see Baja trucks) but will only stiffen up your suspension, your rear end will still twist and "load-n-unload"

traction bars front and rear??

I have a traction bar...a damn nice ladder/shackle setup, so that's not it.

I am in favor of the 42 x 15" rim thing. Big ass sidewalls, but then again, they have their advantage too in ride quality and sidewall flex.

I know you can control a lot of "bounce" with shocks. Mine is UNBELIEVABLY bd with the shocks on "1" versus "5"

Shocks work, that is why I was thinking I needed more "shock"

The reversed shackle theory makes a lot of sense too, but my Heep buddy that is set up like me has a huge bounce problem and he does not have a SR.

Any more ideas??

I have the same problem with my rig. Built a fawkin bitchin traction bar, and thought, killer now I can get it...WRONG!!! Replaced my rear 9000's with a set of 5000's I had in the garage and it helped A LOT!!

I thought after I had completed the trac bar that it was not working, so I had a buddy video me going up a steep ledge around the corner from my place. And my take on the footage......I don't have axle hop any more......I have Cruiser hop. :mad:

How about increasing your spring rate by replacing one of the stock leaves with one from a stiffer set of springs like an old set of Ranchos? I know this will reduce your flex and soft ride, but if the bouncing is that bad you may need to sacrifice a little to prevent breakage.

You definetly had her bouncing real good on those Fordyce steps last year! That was killer to watch!:smokin: What do they call that hill again?

So when are we going to run the Dusy-Ershim trail Craig? Mid June? I'm thinking of skipping the Rubithon this year in favor of the Dusy trail. What do you think? let's plan it! :)

Later bud.

Jimmy


Originally posted by Shipwreck
I think bouncing can be a side effect of doing the front shackle reversal in combination with the spring over. I've seen this happen after the SR on several trucks including my own. With both set of shackles in the rear, the body can easily lurch up from the axles since the pivot points are in the same angle. When the tires hook up and then lose traction, such as on a steep loose incline or on stairsteps, the suspension cycling begins and continues to multiply until you get off the throttle. My cruiser has literally jumped all four tires off the ground when I didn't back off trying to climb some loose steps. Soft springs, increased axle wrap from the SOA and a heavily loaded cruiser all compound the problem.
I have cranked up the shocks and that helped a little but I didn't like what it did to my ride the rest of the time. In my case the two things that helped the most were lightening the load and easing up on the throttle.

i have the same problem with my jeep. i have a traction bar on the rear, rs9000's, and a shackle reversal. i think mine is caused by wrap on the front. i plan to built a anti-wrap bar for the front that is similar to the one on the rear. i just need to get time to build one. keep us posted on what works.:D

what kind of lockers are you running ??

arb front and rear would probubly help
along with the tracktion bars front and rear.
and lower gears.

Originally posted by Land Crusher
what kind of lockers are you running ??

arb front and rear would probubly help
along with the tracktion bars front and rear.
and lower gears.

Explain yourself :confused:

I run a spool in the rear and a Detroit in the front.

I am 100:1 on my gearing.

What will a front traction bar do to help this situation?

Sup?

Late Model Mustangs run a "kicker" shock to control wheel hop.
This shock is mounted almost horizontally like a link arm yet dampens the moment arm effect of wheelhop.

Just a thought!:usa: :beer: :smokin:

Originally posted by wngrog


What will a front traction bar do to help this situation?

Sup?

if your front springs are wrapping this could cause your problem.

Nolen,

I have to agree with Jason on this, did you have this problem with the 38.5 SX's? I have heard of trucks with large sticky tires storing energy in the sidewalls when the tire has traction. When they come to a loose spot all the enery is released suddenly and the truck would jump.

Dropping the weight out of the back would help as there would less downward force on the tires, which means less energy could be stored in the sidewalls. Also by turning the shocks up you are allowing the shock to absorb this burst of enery like shocks are suppose to do.

If the axle is not wrapping up then you might try rasing the pressure in the tires as a test to see if it helps the problem. I have heard of people who do not like Boggers at moab because there is not enough slip in the tire.


Also high 5 is correct as well, if the front end is loading and unloading it can cause the same symptoms. I tend to lean to the back axle as the problem since your going up hill and the majority of the weight is on the back end.

- Keith

with a spool and a detroit you have all most
a solid axel front and rear.

this has got to cause spring wrap ther is
no way I would belive that it dosent.

so put a tracktion bar on the front.


ps. also lower gears and locked front and rear
equals less pedal needed equals less hop.

but previously I did not know what your
gearing or difs were.

does this happen when you try to climb
in 2 wheel drive ?

If it does than im lost.

Originally posted by Land Crusher
with a spool and a detroit you have all most
a solid axel front and rear.
this has got to cause spring wrap ther is
no way I would belive that it dosent.
so put a tracktion bar on the front.
ps. also lower gears and locked front and rear
equals less pedal needed equals less hop.
but previously I did not know what your
gearing or difs were.
does this happen when you try to climb
in 2 wheel drive ?
If it does than im lost.

Dude the shit I am climbing cannot be "crawled" not can it be taken in 2wd.

I have no problem when I am crawling or if I am hammering on my Cruiser at 15* angles or less.

These are serious, loose, ledges that I cannot climb unless I am getting it ON!

I will look into trying more air and possibly a front traction bar.

I still don't understand what a sloid axle has to do with it all :confused:

Nolen after talking to some guys that do hill climbs they felt that it most likely had to do with weight bias and/or spring rate's but mostly the felt that in order for a suspension to work while kicking the ponies the majority of the weight on the vehicle needed to be towards the front using something around 65/35 weight bias and use wide tires and don't let it dig a rut as that's when things break......he runs a rig oversea's on the hill climbs and this is as close as I can get to what your trying to do, except that they do it alot faster.....

Grog,
I am gonna go with the tire sidewall theory.
At low pressure with the beadlocks and getting traction the sidewalls are going to wrinkle and and the tire diameter shrinks slightly.
When the tires break loose the wrinkle irons out and the tires stand up tall.
The truck then bounces up, gravity takes over and brings you back down. The down force helps the tires grip again and the process starts all over.
Thus you bounce.

Watch a drag car with slicks launching for a practical demonstraion of this theory.

Just my W.A.G. but try the higher tire pressure and see what happens.
CAS

Originally posted by wngrog

I still don't understand what a sloid axle has to do with it all :confused:
I think it's because you have a slip-factor of about zero :D

Nolen, with all the mods you've done to Kate, I think it's time to take one more step toward the dark side. Time to lose the forklift engine and put some real power behind those 42's. So what if the tires wind up? With enough power they'll just stay wound up. Nothing like the sound of a V8 at six grand. Hell, even an old fart like me can't resist stuffing the loud pedal just for the sound. You'll never need Prozac.:eek:

Dan

Just curious and kinda off topic............

Does a rear coil suspension help this situation???

I agree with you Dan...I am in the parts collection phase of a V8 conversion.

I have essentially killed what little road worthiness I had with the 2F engine when I installed the 42's.

As for the solid axle theory with no slippage...the first suggestion was to go to dual ARB's. Doing what i am doing is not possible without the lockers engaged, so I would be in the same situation as I am now. Besides...too much crap to go wrong with an ARB. That is why I chose the dspool. I considered ARB in the front, but they did not make one for a 35 pline 9". I am glad I did not, the detroit is unnoticable with the hydo assist.

I am not a fan of coil spring in the rear of a heavy Cruiser. Coil OVERS, yes, but I see the bouncing problem is even worse on coil sprung vehicles. I watched a bunch of TJ decigned rigs at RCAA and most had a problem with the death bounce on hill climbs.

Nolen, forget ARB's, lockers do enhance axle wrap, but you just have to fix the axle-wrap, not sacrifice your lockers. I would say you need a front traction bar, i know i need one, and i only have 35's. Also, your rear traction bar prolly has a little play in it because of the poly bushings. I used Johnny joints, so it has a tiny bit of play, and it hops HARD on loose hill climbs. get someone else to put your rig in about 40:1( whatever combo that would be for you) and rev the motor up high, and dump the clutch. just do this in your driveway, while you stand next to the rig, and watch the rear end. If it wraps at all, even an inch or so of pinion movement, you will get mad wheel hop. I am gonna go coil-over and use heims on the links to try to get rid of it. The air pressure in the tires wil help too, but i suspect that the major factor is axle wrap front AND rear.

good luck!

Does anyone know if WOLF359 gets this kind of bouncing on his 44" tire rig?

I think he has coils in the rear...no leaf springs to deal with.

Nolen -

I think the traction bar issue is wrong, and I know the SR is wrong. I think there are 2 major factors at work here - both already mentioned:

1. Tire windup. Seen it, lived it. 16.s can help, but tire sizes are a bit limited. AIr up a bit. Think about this: the contact patch of a 42 is MUCH bigger at the same pressure than a 38.5 You are hooking up the tires BIG to get bounce, so air up a bit!

2. Spring rate. You went back to stockish springs right? Even if you were still running teh Alcans, you have massively exceeded teh unsprung weight the suspension was working with. What is the weight increase per corner from the 42, let alone the big dog axles AND the added leverage of being wide....

I would try adding a leaf or going for some springs with an addition 100 lbs of spring rate over what you have now.

HTH,

Jim

I'm inclined to believe that your problem is *mostly* related to the spring rate. I second TLCobsession, either add some springs or go with some custom ones...