Do heavier tires require OEM shocks upgrade? - JeepForum.com
 
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post #1 of 8 Old 02-26-2019, 07:26 PM Thread Starter
pataraco
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Do heavier tires require OEM shocks upgrade?

Hi,

Rig: 2016 Rubicon HardRock
Original Tires: BFG Mud-Terrain KM; 255/75R17 ~ 47 lbs
New Tires: BFG All-Terrain KO2; 285/70R17 ~ 58 lbs

I got a bigger size on the advice of tire salesman that said those are stock on the 2018's now and that that size is more common, so easier to find... whatever!
I compared the sizes with a tire calculator and they are ~ 1/2" taller and ~ 1" wider, so i figured, yeah, wider footprint more better (e.g. traction, wear, stability etc.)

BUT, now when I hit bumps, everything seems all "jiggly" now. Like the tires are not staying/sticking on the ground and the stock shocks can't handle the added weight.

Do i need to upgrade my shocks?
If so, how do i determine which to get? Are they "weight" rated or something?

Also, if i do need to upgrade, I'm thinking about getting some that have the "ride sensitivity" dial. Do those actually work? Is it worth it? I'd probably just leave it on the "strongest/stiffest" setting, i don't mind a rough ride.

Thanks for any help/feedback!

Cheers!
Patrick


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post #2 of 8 Old 02-27-2019, 08:55 AM
Fourtrail
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Check the air pressure in your tires. The tire changer likely inflated them to the sidewall pressure which is way too high for your Jeep. You should not need to replace your shocks for that slight increase in tire size/weight.

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post #3 of 8 Old 02-27-2019, 09:41 AM
biffgnar
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The few extra pounds of tire weight is a rounding error compared to the weight of the jeep that acts on the shocks.

Depending on exactly what is happening, you could have suspension components/bushings wearing out (e.g. control arms, track bar). Bigger tires will highlight issues like that sooner as the bigger tires do make it harder for the links to keep the axle firmly located. Your jeep really isn't that old though.
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post #4 of 8 Old 03-10-2019, 02:07 PM Thread Starter
pataraco
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Yeah, they pumped them up to 45 PSI.
But I've had my old ones up to 45 before and didn't have the same "issue" .

I've ordered some Fox IFP 2.0's all around (Stabilizer too) cuz I can't stand the "shaking).

I'll let y'all know how it goes.

Thanks!

Cheers! O|||||||O ~Patrick
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post #5 of 8 Old 03-10-2019, 02:09 PM
biffgnar
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The shocks are not your problem. You are wasting money. And that Fox stabilizer actually causes problems.
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post #6 of 8 Old 03-10-2019, 02:51 PM Thread Starter
pataraco
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What? Seriously? What kind of problems? Is it just the Fox brand?

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post #7 of 8 Old 03-10-2019, 05:33 PM
biffgnar
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Quote:
Originally Posted by pataraco View Post
What? Seriously? What kind of problems? Is it just the Fox brand?
That Fox stabilizer is gas charged that basically wants to push the piston to full extension at all times. That works well in shocks where there is a constant load and a compression/rebound bias that has to be balanced. A stabilizer though should be a neutral 50/50 setup. I believe if you use the search function you will find plenty of discussion. For a stabilizer a generic parts store stabilizer works just fine and is a lot cheaper.
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post #8 of 8 Old 03-11-2019, 06:26 PM
222Doc
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his PSI is way to high for the load of the tire on a jeep. My excursion with a 7.3 that is close to 8k pounds is at 47 front and 44 rear its still to high. If you do the math of the tire at its side wall ratted MAX<<<<PSI is for the load of it at max weight and that numbers is on the side wall as well. Each tire on Ex can hold 3800 pounds at 65 psi,, about. so if the tires are at MAX psi they can roll 15,000+ lbs. basically two tires could hold it up like a motor cycle at 65 psi. But at 8k they are way over inflated. no shocks going to help that.

My 12 jkr runs D rated 37s. At 27 front 25 rear. It could be lower by the math BUT we dont want to get to low at high speeds. Thats not to low on a 5k pound Jk. i run it at 8 psi off road no beads locks no issues. could run it lower. It falls off at 4psi. that i know had one go low on a 3 day trail. If I ran 45 psi in the Rubicon i would not even want to drive it on 33+. Check your weights do the math add 20% maybe. Now some vehicles can be nose heavy, like our EX. bias the figures. how you end up at say 37/33 instead of 35/35.

at full max psi or even close that jeep would need so much weight on it would bend the axles, just saying...........as it cant even hold that much weight.

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