ive been experiencing rough / harsh ride with expansion joints and road cracks at low speed no problem with speed bumps with my lc100 it used to be an ahc which i convert to conventional suspension stock no ahc springs, torsion and shock. i changed my tires to oem dunlop tg28 same story tire pressure is 28 psi front and rear and help where to start or whats the cause?
harsh ride / rough ride on expansin joints
- Thread starter vxlc80
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What's your lift height now? As the front and rear control arms move more away from stock/near horizontal position (with lifted rigs), it takes more force to move them vertically...as the first part of their respective travel is not 100% vertical; the fronts have to move horizontally a little before they start moving vertically; ditto for the rear control arms. I've noticed the same change in my suspension...but my E rated tires don't help. Nothing can be done with the front control arm positioning (well within a reasonable amount of $ anyway 
).
I would think at 28psi the tires would be more compliant...what size are you running?
).I would think at 28psi the tires would be more compliant...what size are you running?
- Thread starter
- #3
What's your lift height now? As the front and rear control arms move more away from stock/near horizontal position (with lifted rigs), it takes more force to move them vertically...as the first part of their respective travel is not 100% vertical; the fronts have to move horizontally a little before they start moving vertically; ditto for the rear control arms. I've noticed the same change in my suspension...but my E rated tires don't help. Nothing can be done with the front control arm positioning (well within a reasonable amount of $ anyway
I would think at 28psi the tires would be more compliant...what size are you running?
285/75r16 tires. height is stock height to non ahc LC with 1" of rake. when i hit expansion joints or road cracks and road irregularities it is transmitted to the whole truck
This issue just creeped up on me two days ago with E-Rated BFG/ATs (which I've had for years) and no AHC. Yesterday I jacked up the front end, pulled the skid plates and all I found were oil and steering rack leaks.
Speed bumps feel just fine on mine too, Do you feel it in the floor board when it happens? I'm going to check the torsion bar mounts today, but i can't think of what suspension part could cause noise only at high speed bumps but not large speed bumps at less than 10MPH.
Speed bumps feel just fine on mine too, Do you feel it in the floor board when it happens? I'm going to check the torsion bar mounts today, but i can't think of what suspension part could cause noise only at high speed bumps but not large speed bumps at less than 10MPH.
I fully believe that Land Crusiers and most other vehicles rely on tire sidewalls to absorb the sharp, small, but very noticeable bumps and cracks such as that. Then the suspension takes on the larger items as it flexes and moves the springs and shocks. When I put e rated tires on stock suspension...instant difference in smooth ride on expansion joints, small depressions in road, and offroad....
it is a compromise....better ride equals lower sidewall strength/durability. Same as tire weight (except for new kevlar ply)...better durability and strength is heavier weight. Then ad a stiffer suspension on top of the heavier, stiffer, tougher tires and you have compounded your ride again.
It does not mean there is anything wrong...it just means you crossed the line from mall cruiser to offroad vehicle. If you want same ride as stock...then keep stock suspension and keep your tires C rated and same size as stock. Otherwise there will be changes that are very noticeable...
I prefer having less nose dive, less body roll, and less rubbing over comfort over cracks and small bumps. Also, I tend to air down my tires offroad as much for ride comfort and to keep my kidneys from bleeding as I do extra traction...LOL
E rated Nitto Trail Grapplers will let you know you should have GONE PEE just one more time before hitting trail...in a hurry.
it is a compromise....better ride equals lower sidewall strength/durability. Same as tire weight (except for new kevlar ply)...better durability and strength is heavier weight. Then ad a stiffer suspension on top of the heavier, stiffer, tougher tires and you have compounded your ride again.
It does not mean there is anything wrong...it just means you crossed the line from mall cruiser to offroad vehicle. If you want same ride as stock...then keep stock suspension and keep your tires C rated and same size as stock. Otherwise there will be changes that are very noticeable...
I prefer having less nose dive, less body roll, and less rubbing over comfort over cracks and small bumps. Also, I tend to air down my tires offroad as much for ride comfort and to keep my kidneys from bleeding as I do extra traction...LOL
E rated Nitto Trail Grapplers will let you know you should have GONE PEE just one more time before hitting trail...in a hurry.
Body mounts might be old
You might check the body mounts. Your cruiser has some years on it and the rubber may be (probably is) shot. The body mounts also absorb small high-frequency shocks. If they go you then everything would feel a little more edgy.
You might check the body mounts. Your cruiser has some years on it and the rubber may be (probably is) shot. The body mounts also absorb small high-frequency shocks. If they go you then everything would feel a little more edgy.
Nice suggestion and great first post...welcome
. I can duplicate the sound by rocking the body via the roof rack now. Just have to find somebody to rock it while I search...OP...what are you finding?
solved my problem!!! The body mounts are lose tightened about 2 to 3 threads
Pardon the ignorant newbie question, but where are the body mounts located?
outboard of the frame rails. just slide underneath and you'll see the rubber pucks/bolts. page DI-15 on the FSM shows them. 5 per side.
anyone torque specs?
FSM doesn't have them, must have to get the collision manual? Google turns up references to 35 ft lb for an FJ cruiser. Imagine they'd be in the same ballpark. I don't think you'd want them cranked down or they would degrade the ride.
Bear in mind that the torque specs will vary depending on the components you're using. Rubber vs. urethane, grade 8 vs. grade 5 (yikes, you must buy your bolts at the home despot) vs. stainless...
Most body mounts are between 30-50 lbs/ft for radiator supports and rear body mounts, 50-70 lbs/ft for front body mounts on stock vehicles. This is pretty universal from manufacturer/model to manufacturer/model. Stay in those ranges and you should be fine.
Most body mounts are between 30-50 lbs/ft for radiator supports and rear body mounts, 50-70 lbs/ft for front body mounts on stock vehicles. This is pretty universal from manufacturer/model to manufacturer/model. Stay in those ranges and you should be fine.
I have the same problem, after converting AHC to stock (OEM) conventional LC suspension.
The stock non-AHC suspension is just stiffer, I think. Especially the rear. The effect is most pronounced with smaller, jittery type inputs such as expansion joints, etc.
My tires are OEM type, Michelin LTX M/S 275-70R-16.
Man, the AHC must be a really smooth ride! I thought mine was soft with the factory springs. With the OME bars and 866 springs it's nice and tight but still pliable
princess: thinks it's a little on the firm side). I think it will mellow perfectly with some bumpers and sliders weighing it down.
I've noticed in the last couple days since the roads are beginning to freeze here that those expansion joints are starting to get more rigid creating a jarring noise.
I looked at my body mounts and they are shot! The bolts look all rusted up also. I'm not even sure I should try tightening them as the bolt(s) will probably shatter. Can I just order some new ones and install them? How hard is this to do? Are there any instructions?
I looked at my body mounts and they are shot! The bolts look all rusted up also. I'm not even sure I should try tightening them as the bolt(s) will probably shatter. Can I just order some new ones and install them? How hard is this to do? Are there any instructions?