4th Gen Rough Ride Diagnosis Help

[Austin12345]

Hey guys,

I have a 2007 SR5 2wd. After looking through many threads and not finding something that has worked for me, I decided to post my own. I'm having trouble diagnosing a harsh/choppy ride. This mainly occurs over smaller, uneven bumps in the road, which is to be expected but I wouldn't think to the level I am experiencing.

Here is my current set up:
Front -
- Dobinsons MRR 3 way adjustable coilovers (HS compression on softest, LS on 2 clicks, rebound 2 turns)
-JBA UCA
- 4" lift spindle
- Stock front bumper

Rear -
- Toytec Superflex 2" coils with 1.5" daystar spacer
- Dobinsons gs59-575 long travel twin tube shocks
- Stock rear bumper

Tires -
Pro Comp Sport AT 285/70/17 load range D


2 weeks ago I did a front end over haul with new inner & outer tie rods, UCA ball joint, new oem LCA, and the dobinsons coilovers. This is coming from Bilstein 5100's in the front and OME 885 coils which were topping out and the ride was horrible on top of worn LCA bushings and loose inner tie rods. After I installed the new parts, I could tell the handling/ride improved over bigger bumps but the harshness over uneven terrain or cracks in the road is still pretty rough and I can feel everything. I have adjusted both compression knobs as well as rebound but it still does not fix the problem, although it helps slightly when on softest. Took it to an alignment shop after the install and the tech said it lined up nicely.

My best guess is that it is the load range D tires with ~65,00 miles on them (even set to 30 psi, normally about 35) which have some slight uneven wear due to alignments not being perfect because of worn LCAs and previous over extended geometry with the 885's. This, along with added unsprung weight of the beefy 4" spindles. The rear is smoother than the front but still not great, most likely due to solid rear axle but still choppy which leads me to believe it is probably tires.

I came across a thread yesterday that suggests it could be UCA bushings binding, which I linked below. During install, while the UCA was disconnected I noticed that there was a good amount of resistance after pushing it about 10 deg. above parallel to the ground. I might loosen the thru bolt and drive up and down the driveway and see if that does anything.

Sorry for the long read but please let me know if you have any suggestions or if this is just the way it's gonna be, thanks!


Link to thread:
bouncy ride after new LCA install?

 

[stevelikesrhino]

More rigid bushings does contribute to a harsher ride, but nothing compares to those heavy duty 4 inch spindles. These probably weighs twice than stock spindles. Switching back to stock with close to 3 inch lift will definitely help.

 

[inscarguy]

When you installed the control arms, did you tighten them while it was off the ground or did you leave them loose until the vehicle was on the ground and then tightened them. If you tightened them off the ground that will cause binding because the arms do not have the vehicles weight on them and when you hit a bump they want to return to the wrong position by over extending the bushing. By now it's possible that the arm bushings are compromised, check the bushings for cracks or if the sleeve is floating in the bushing.

 

[Austin12345]

It's been a while since the install so I don't remember exactly how much I tightened them before torquing while on the ground but I probably should have left them looser. I plan to swap tires with my friend who has an '03 on stock tires to test out the ride as well as loosen the thru bolts this weekend to pinpoint the issue better.

 

[TrueNorth4Runner]

Hey guys,

I have a 2007 SR5 2wd. After looking through many threads and not finding something that has worked for me, I decided to post my own. I'm having trouble diagnosing a harsh/choppy ride. This mainly occurs over smaller, uneven bumps in the road, which is to be expected but I wouldn't think to the level I am experiencing.

Here is my current set up:
Front -
- Dobinsons MRR 3 way adjustable coilovers (HS compression on softest, LS on 2 clicks, rebound 2 turns)
-JBA UCA
- 4" lift spindle
- Stock front bumper

Rear -
- Toytec Superflex 2" coils with 1.5" daystar spacer
- Dobinsons gs59-575 long travel twin tube shocks
- Stock rear bumper

Tires -
Pro Comp Sport AT 285/70/17 load range D


2 weeks ago I did a front end over haul with new inner & outer tie rods, UCA ball joint, new oem LCA, and the dobinsons coilovers. This is coming from Bilstein 5100's in the front and OME 885 coils which were topping out and the ride was horrible on top of worn LCA bushings and loose inner tie rods. After I installed the new parts, I could tell the handling/ride improved over bigger bumps but the harshness over uneven terrain or cracks in the road is still pretty rough and I can feel everything. I have adjusted both compression knobs as well as rebound but it still does not fix the problem, although it helps slightly when on softest. Took it to an alignment shop after the install and the tech said it lined up nicely.

My best guess is that it is the load range D tires with ~65,00 miles on them (even set to 30 psi, normally about 35) which have some slight uneven wear due to alignments not being perfect because of worn LCAs and previous over extended geometry with the 885's. This, along with added unsprung weight of the beefy 4" spindles. The rear is smoother than the front but still not great, most likely due to solid rear axle but still choppy which leads me to believe it is probably tires.

I came across a thread yesterday that suggests it could be UCA bushings binding, which I linked below. During install, while the UCA was disconnected I noticed that there was a good amount of resistance after pushing it about 10 deg. above parallel to the ground. I might loosen the thru bolt and drive up and down the driveway and see if that does anything.

Sorry for the long read but please let me know if you have any suggestions or if this is just the way it's gonna be, thanks!


Link to thread:
bouncy ride after new LCA install?

This might be a big factor, putting aside all the other potential issues.

My father's car, and my old jeep, both had scalloped tires from work out shocks, and let me tell you, the ride sucked.

Also, as you mentioned, UCA/LCA geometry has a HUGE impact. My last vehicle was a 1997 GMC Safari AWD that I had lifted. I ran the front up to 3" of lift, so the control arms were under more extreme angles.

Holy crap, what a bad ride. Like on wagon wheels down a bumpy road. Soon as I dropped down to 2.25-2.5", the geometry mellowed out and the ride became pretty tolerable, considering the lift and shocks etc. Went from wooden wagon, to more like driving a stock fleet truck.

So definitely check those angles, and once you've gone through it all with a find tooth comb, try to get some better tires (wouldn't want to ruin yet another set, if they aren't the cause)

Keep us posted!

 

[Austin12345]

Update

This past weekend I finally had the time to work on the 4Runner. Here's what I did:

New tires: BF Goodrich KO2 285/70/17 load range C (10 lbs lighter than pro comps)
Bold on panhard correction by Dr. KDSS
Moog inner tie rods
Loosened UCA thru bolt and regreased

The ride is much smoother with the new tires. I had gotten used to feeling the tire choppiness as it rolls and now there is much less road noise from the pro comps which had started cupping. Not sure if it's placebo but the less unsprung weight seems to have helped in acceleration too.

Did a lot of research about panhard corrections and how they help the rocking motion and it seems to have done the job. No more lateral jarring motion and the axle is now centered where before, the right tire stuck out over an inch more than the left.

I ordered and regreased the UCA bushing with Mobil XHP 222 special recommended by JBA. The bushings are pretty tight in there even with the thru bolt loosened and they started to bulge so I took it down the road a couple times with the bolt loose and the zerks out and a lot of grease came out and the bushings went back in place. I torqued the thru bolt with the zerks out. The front end and wheel feel much more stable and I do not have the sloppiness I was feeling. This was still occurring for a few days after the new tie rods were put in.

I plan to eventually swap out the JBA bushings for the updated design that inhibits them from bulging. I noticed one of the bushings on the passenger side was bulging with enough force to bend the metal washer and it stayed slightly bent after re-torquing.

Overall, the ride is a lot better although I do still have the symptoms, just reduced now. I'm sure this is part from me overanalyzing the handling over any bump but I've got it narrowed down to the rear end tending to buck and be firm over bumps. I'm chocking this up to the rear set up with the 1.5" spacer on the superflex springs and want to eventually swap them out for a longer progressive spring. I'll tweak the front adjusters to see if I can get it dialed more but for the most part I am happy with the results.