Bouncy Jeep (Newb Question)

[xcantuaj]

I will lower to 30-32 and see how it goes. Bouncy meaning ....I hit a bump and the suspension keeps the jeep bouncing all over the place. I know it wont be like a Cadillac but if there is something I can upgrade to help then I'm good with that.

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[WXman]

Bought my JL slightly used. Already came with 35's and 2inch lift (Mopar). I don't know much about suspension.....what upgrade will settle the jeep down and cushion the bumps.

Track bar relocation brackets are the answer, in my opinion. The horrible ride quality and yawl after a 2" lift is due to the altered geometry of the linkages.

Drop brackets for the control arms will also smooth out the ride some as well.

 

[Zenk]

How are those working out?

And, what backspacing?
On what width rim?

Working well so far... Running the Mopar Beadlooks(8" width, 4.4" backspace) with them. If you run them with the Beadlock, they are 8.5" width.

 

[Uhdinator]

I will lower to 30-32 and see how it goes. Bouncy meaning ....I hit a bump and the suspension keeps the jeep bouncing all over the place. I know it wont be like a Cadillac but if there is something I can upgrade to help then I'm good with that.

Does your used jeep with lift have shock extension brackets with OEM shocks? If so......remove the extensions and get 2-3" longer shocks that are better and can dampen the bigger tires better. The RS5000X's that I installed reduced the side to side sway and the jeep doesn't have the slight shudder that happens when you hit bridge seams and RR tracks, etc.

A good rule of thumb is 10% pressure increase when tires warm up. So at 30psi cold when you have driven a while at highway speeds, The psi shouldn't go up more than about 3 psi. If its more than that you are too low and the tires are building up too much heat from under-inflation. More heat = more pressure.

32 might be better for 4 doors and 30 for 2 doors due to weight difference. The front of the jeep is heavier so you could run a little less psi rear than you do in the front. Door jam label recommended psi is an average meant to provide best trade off of MPG and ride. I little lower improves ride and more even tire wear, especially with bigger tires.

The other factor is bigger and wider than stock tires give a bigger contact patch and weigh per square inch is reduced, as its spread out over a larger contact patch, hence running lower than stock pressure is possible and lessens the center of the tire wearing out first.

 

[mwilk012]

I will lower to 30-32 and see how it goes. Bouncy meaning ....I hit a bump and the suspension keeps the jeep bouncing all over the place. I know it wont be like a Cadillac but if there is something I can upgrade to help then I'm good with that.

For how long? Did you drive the Jeep before the lift was installed at all?

 

[xcantuaj]

I bought it used with lift and 35's. I test drove a couple with stock tires....don't remember all of the bouncing. I have gotten use to it...just wondering If I'm missing an upgrade that can help.

 

[OnlyOne]

I bought it used with lift and 35's. I test drove a couple with stock tires....don't remember all of the bouncing. I have gotten use to it...just wondering If I'm missing an upgrade that can help.

That mopar lift is probably more like 3”. Get some track bar relo brackets and center your axles. If it was just 2” I wouldn’t worry about it. Most of it is coming from your tire pressure. The rest is most likely coming from odd angles the lift has created.

 

[wvgasguy]

Not here as an expert, just wondering out loud. An E rated tire is pretty much self supporting with the thick stiff sidewalls. I'm left wondering if a person only put say 29 to 30 psig in them then is the tire really inflated enough to be safe if a dangerous highway maneuver was needed to avoid something. You might get a false sense of tight handling until you reached the limits of the sidewall and then get major flex without adequate air. I understand airing down for rock climbing, but I'm thinking driving at 70 mph on a highway might need a little higher pressure. Just a thought, I'm not an expert, just drove a million + miles and I try to avoid intentional issues. Don't really know if tire manufacterures establish a minimum safe tire pressure

 

[OnlyOne]

Not here as an expert, just wondering out loud. An E rated tire is pretty much self supporting with the thick stiff sidewalls. I'm left wondering if a person only put say 29 to 30 psig in them then is the tire really inflated enough to be safe if a dangerous highway maneuver was needed to avoid something. You might get a false sense of tight handling until you reached the limits of the sidewall and then get major flex without adequate air. I understand airing down for rock climbing, but I'm thinking driving at 70 mph on a highway might need a little higher pressure. Just a thought, I'm not an expert, just drove a million + miles and I try to avoid intentional issues. Don't really know if tire manufacterures establish a minimum safe tire pressure

All tires have load ratings based on tire pressures. They rate the amount of weight they can hold, with tire pressures. E rated tires are 10 ply “rated”. They don’t really have 10 plys. Some D rated tires have higher load ratings than E’s depending on size. So basically you can look at their charts and see what pressures to run with the weight you’re carrying, safely. They aren’t going to roll over at 28 psi. Hell I’ve run over 30 miles on 10 psi on mine before getting back to Moab. They were a bit gooey but still felt descent.

 

[alrola]

I had mine at 35... not brave enough for 32. I took to dealer for unrelated issue and I happened to mention the car wondering at highway speeds and how harsh the ride was on my mopar lifted 35" KO@ so they jacked up the tire pressure to 42 because they believed it would help. He said (shop foreman) that it would wonder less on the road and be less affected by imperfections.
Seems counter intuitive to me... thoughts ?
I ride on 35 x 12.5 KO2 lifted mopar 2".

 

[wvgasguy]

All tires have load ratings based on tire pressures. They rate the amount of weight they can hold, with tire pressures. E rated tires are 10 ply “rated”. They don’t really have 10 plys. Some D rated tires have higher load ratings than E’s depending on size. So basically you can look at their charts and see what pressures to run with the weight you’re carrying, safely. They aren’t going to roll over at 28 psi. Hell I’ve run over 30 miles on 10 psi on mine before getting back to Moab. They were a bit gooey but still felt descent.

I understand needing "gooey" tires while off roading. I'm specifically talking about running them on low pressures while driving on the highway so they are not too stiff. Gooey does not sound like what I want at 75 mph on an interstate or 55 mph on a curvy hilly road.

 

[OnlyOne]

I understand needing "gooey" tires while off roading. I'm specifically talking about running them on low pressures while driving on the highway so they are not too stiff. Gooey does not sound like what I want at 75 mph on an interstate or 55 mph on a curvy hilly road.

I just answered that in my post. At 28 psi there is still plenty of load capability with an even max loaded JL to safely run down the highway at any posted speed. At the end of my post I was explaining how they feel at 10 psi. not 28. Big difference with these light vehicles.

 

[OnlyOne]

I had mine at 35... not brave enough for 32. I took to dealer for unrelated issue and I happened to mention the car wondering at highway speeds and how harsh the ride was on my mopar lifted 35" KO@ so they jacked up the tire pressure to 42 because they believed it would help. He said (shop foreman) that it would wonder less on the road and be less affected by imperfections.
Seems counter intuitive to me... thoughts ?
I ride on 35 x 12.5 KO2 lifted mopar 2".

If those are E rated even 32 PSI is high. You guys need to understand that these tires have a huge load range. They are not meant for such a light vehicle. They are going to be stiff. Airing them up to 42 psi will make them fell like you're driving on bowling balls.

 

[LagunaJim1]

There's nothing wrong with 30 or 32 in those.

 

[Blakeypoo702]

I bought it used with lift and 35's. I test drove a couple with stock tires....don't remember all of the bouncing. I have gotten use to it...just wondering If I'm missing an upgrade that can help.

I have 35 Ridge grapplers on my jl. I run mine at 28 psi and it’s a world of difference then say 35 psi. Air them down and all your problems will be solved

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