Ride quality question

4Lo4Sho

4Lo4Sho

TJ Enthusiast
Supporting Member
Joined
Oct 31, 2023
Messages
239
Location
So-Cal
2004 TJ rubicon
4.5 RE long arm lift
Fox 2.0 adjustable reservoir shocks with levels 1-8 setting knobs.
Hydro bumpstops

Overall, the jeep rides pretty great, with a bit of harshness on rough roads, but nothing too bad.

On certain parts of the freeway though, the Jeep gets to "bucking" with very little of the suspension doing any damping (it would seem). I drive the same section in a Civic or our F150 and it's just the very slightest sensation as opposed to the TJ, where the suspension seems like it's absorbing very little of the road's corrugations. (probably only 40-50mph in these areas.)

Anyone have guidance on the proper setting for the FOX shocks with a heavy tire carrier back there? I can't find anything online or in forums.

thanks!,
 
Mess with the adjusters until you find something you like better than the others. Other than a retune, that is all you can do.

This assumes the shock travel bias is what it ought to be at about 50/50 from ride height.
 
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I run the same shocks, all 4 corners set to 1 on the road. I also have JKS dual rate 3in springs and the harshness reduced a lot. As far as the bucking issue, I would think more weight in the rear would help. I have not put mine on any scales to check, but I think I have a rear weight bias and I am not getting the bucking you are describing.
 
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XCRN said:
I run the same shocks, all 4 corners set to 1 on the road. I also have JKS dual rate 3in springs and the harshness reduced a lot. As far as the bucking issue, I would think more weight in the rear would help. I have not put mine on any scales to check, but I think I have a rear weight bias and I am not getting the bucking you are describing.
Click to expand...

The only thing the springs can do is change the ride height, which potentially changes the shock travel bias into a better position for the shocks to perform better than before.
 
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4Lo4Sho said:
2004 TJ rubicon
4.5 RE long arm lift
Fox 2.0 adjustable reservoir shocks with levels 1-8 setting knobs.
Hydro bumpstops

Overall, the jeep rides pretty great, with a bit of harshness on rough roads, but nothing too bad.

On certain parts of the freeway though, the Jeep gets to "bucking" with very little of the suspension doing any damping (it would seem). I drive the same section in a Civic or our F150 and it's just the very slightest sensation as opposed to the TJ, where the suspension seems like it's absorbing very little of the road's corrugations. (probably only 40-50mph in these areas.)

Anyone have guidance on the proper setting for the FOX shocks with a heavy tire carrier back there? I can't find anything online or in forums.

thanks!,
Click to expand...

The bucking sounds more like the front and rear not getting along, having to do with the timing of the response of the rear, ideally a little faster than that of the front so that they both "settle" together after an event like an expansion joint in a concrete highway.

The difficulty arises where TJs have such a short wheelbase and such variable configurations of loaded weight distribution that they far more rarely line up with a well -timed suspension.

As mentioned above, you can try adding weight in the rear to slow it down (harder to remove weight if it needs sped up), or try some different settings with your clickers font vs rear and see if you can get it riding better.
 
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jjvw said:
The only thing the springs can do is change the ride height, which potentially changes the shock travel bias into a better position for the shocks to perform better than before.
Click to expand...

I personally felt enough of a difference at the small actions that result in harshness going from BDS linear rates to JKS dual rates on the same horribly maintained city roads I take to work everyday. Not a night and day difference, but still a noticeable difference.
 
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Ok, so having set my tires to 26psi and my adjustable Fox’s to 1 on the damping setting- Other than much louder tires and decreased fuel mileage, my seat-of-the-pants’ometer hasn’t detected earth shattering in the ride quality area.

Didn’t expect much from these changes but it was worth a try. (Thanks y’all!)

My thoughts from researching this topic a bit:

  • Our long arm kit, while not ideal by some folks experience, works really well for us right now and we’ll be leaving it alone for the time being. While not Johnson valley, the local 7/10 trail we just took it on was gobbled up by our dialed in setup.
  • Our springs are the normal 4.5” RE setup and while a shop offered dual rates as an idea, reading info from @mrblaine and others, I’m thinking the springs will be left alone too.
  • That leaves tires and shocks.
    • Tires are fresh pat’s that’ll be replaced probably in a year or so, for something a bit more streetable like bfg’s KO2’s or Toyo’s
    • Regarding shock’s: i think what i want to do is follow the advice i’ve seen to determine where the shock lives in it’s stroke to see if they’re maybe setup wrong now that the rig is as heavy as it is (maybe they were setup when the rig was closer to stock weight and springs have sagged a bit) OR maybe they’re simply in need of a service (if that’s possible with these) or replacement.
    • One reason this resonates with me is that when i took my heavy toolset out of the jeep and also took the hard top off for a while, i would say that the ride quality improved by a fair amount (10-20%), meaning smoother over freeway joints and less bucking overall. I would attribute this to possibly unloading the suspension a bit and thereby changing where the shock was working along it’s stroke design?
 
Last edited:

IMG_3474.jpeg

 
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Found some information on our shocks:

Fox, racing remote, reservoir shocks bought in 2010
  • Front 980–02–304 (29 inches/18 inches)
  • Rear 980–02–303 (25 inches/15 inches)
Went outside and measured and each shock only has about 4 inches of the shaft showing below the shock body, sitting on our flat concrete parking pad with a modest amount of tools, a half a tank of gas and not much else.
My initial thoughts:
  • these shocks being rated at a 6 1/2 to 8 inch lift are far too long for this application. Probably chosen as a “long travel “ shock?
  • With only 4 inches of the shock showing below the shock body, I’m thinking that this TJ weighing in at 4800 pounds is probably exacerbating the compression of the shocks.
  • I’m thinking that a shock that is more suited to a 4 1/2 inch lift in the 29 inch/15 inch size for the front and a 23 inch/13 inch size in the rear might be a possible path towards improving the ride quality by allowing the shock to have more of the shaft exposed?
 
Fronts
4” of shaft exposed.
21.5” ish overall length (29” possible)

IMG_8858.jpeg


Tape is equal to bottom of shock mount. Just pulled away as soon as i was snapping pic.
IMG_8859.jpeg
 
4Lo4Sho said:
Fronts
4” of shaft exposed.
21.5” ish overall length (29” possible)

View attachment 537205

Tape is equal to bottom of shock mount. Just pulled away as soon as i was snapping pic.
View attachment 537206
Click to expand...

Don't include the little rubber donut in your shaft measurement. That is a jounce and will eventually break apart and disappear if you use the full shock travel.

Also, make it easier on us and post the travel amount along with the amount of up travel and down travel from ride height.
 
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jjvw said:
Don't include the little rubber donut in your shaft measurement. That is a jounce and will eventually break apart and disappear if you use the full shock travel.

Also, make it easier on us and post the travel amount along with the amount of up travel and down travel from ride height.
Click to expand...

(y) Will do, here’s some factory info i have already.

IMG_8861.jpeg
 
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