Eco diesel Suspension bottoming out on normal roads

[Gruffid]

It looks like there is a total of 2-5/8” of available up travel (to the metal cup lip). Can someone else with stock suspension get a measurement for comparison?

Renegade,

yes, it looks like about 2-5/8” from the bottom of the spring to the bottom of the metal cup lip. However, the clear/translucent bump stop is at the 1.5” line. So, that’s what I’m calling up travel.

do you disagree? If so, why?

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[Renegade]

Renegade,

yes, it looks like about 2-5/8” from the bottom of the spring to the bottom of the metal cup lip. However, the clear/translucent bump stop is at the 1.5” line. So, that’s what I’m calling up travel.

do you disagree? If so, why?

That cellular foam bump stop/jounce bumper will compress completely into the cup. That is your available suspension up travel.

 

[Gruffid]

I don’t suppose you have video of that collapse do you?

While I acknowledge my finger leverage inside that spring is very weak, it seems very firm. I also acknowledge that the weight of the front end can exert a lot more pressure than my finger squeezing through the coil.

I would just like to see how that bump stop collapses.

 

[Renegade]

I don’t suppose you have video of that collapse do you?

While I acknowledge my finger leverage inside that spring is very weak, it seems very firm. I also acknowledge that the weight of the front end can exert a lot more pressure than my finger squeezing through the coil.

I would just like to see how that bump stop collapses.

I don’t have video, but I’ve tested and confirmed it.

So, can someone else measure their stock up travel now? It really doesn’t matter if it’s to the cup or to the bump stop/jounce bumper as long as we have a Rubicon-Rubicon comparison. The reason I suggest the cup is because some people (like me) have swapped to different bump stop/jounce bumpers.

 

[PackMule]

I have a stock Rubicon Diesel with 35's but no other weight mods or lift, and have noticed the same performance. I'll get out tomorrow and do some measurements.

I've had it a little over a month. Three trail rides and I cant count the number of bump stop "bottom out's" i've had. It will sometimes bottom out at 20mph over washboards, a medium sized pothole, medium sized rock. Also bottomed on a normal asphalt 'woops' that was caution signed at 20mph that I took at 25-30mph. My JKR with AEV 2.5 dual sport lift would do the same exact circuit significantly faster and never notice it.

 

[Gruffid]

Pack mule,

thanks for the assist!

I guess I’m glad I’m not the only one, but I expected jeep to compensate better for the higher weight loading of the diesel on the suspension

 

[sdk131]

Pack mule,

thanks for the assist!

I guess I’m glad I’m not the only one, but I expected jeep to compensate better for the higher weight loading of the diesel on the suspension

right...this seems like some sort of oversight and/or production issue (wrong springs being used on the line or something). I don't see how a vehicle touted for offroad capability is coming with only 1.5" or so of uptravel.

 

[CrazyCooter]

Bummer if they missed the mark on this. Wonder if there is any difference in the oem shock part numbers between gas and Eco?

This is exactly why I wont install gasser lift springs and shocks on my Eco......I want the correct solution!

 

[PackMule]

Renegade,

yes, it looks like about 2-5/8” from the bottom of the spring to the bottom of the metal cup lip. However, the clear/translucent bump stop is at the 1.5” line. So, that’s what I’m calling up travel.

So my stock JTR Diesel front bumpstop clearance is just slightly more than yours. I'm at 2-15/16. That is from the metal cup rim down to the surface of the axle pad where the bumpstop would first make contact. I couldn't see the measurement to the tip of the bumpstop, but assuming the same length as yours I'd have 1-13/16. So I'm just a few 16's taller than you, and that could just be difference in build (full disclosure, I still have the stock plastic bumper).

as a comparison, I did the same measurement on my JK with a 2.5 AEV lift, and it is about 4.25, and that is from bumpstop to a much taller rubber spacer included in the dualsport lift kit to prevent TOO much uptravel, presumably to prevent damage to shock, or hitting a stock fender.

JK with 2.5 dual sport lift

So, referencing the Accutune rule-of-thumb comment above, it looks like the JT front travel in general is designed short of what would be rule of thumb for crawling.

 

[PackMule]

Stock suspension only has a few of inches of up travel. To give you an apples to oranges comparison, I’m running 3” of front lift with 2” of bump stop extension, and have 4” of up travel on my gas Rubicon (with a winch and stubby bumper). This equates to about 3” of up travel if it had stock suspension. My point is, there’s often less up travel than you would expect to begin with. It’s worth the OP measuring though.

-Snip-

Accutune recommends 4” of up travel for rock crawling, 5” for trail riding, and 7” for desert running.

So my 2-15/16 measurement seems consistent with your pre-lift estimate of 3" on your gasser. Depending on stock spring stiffness, the extra weight of the diesel might compress that remaining 3" on quicker than on a gas model.

This thread has been very good informationally for me and my planning as well. I really don't need/want much more lift, as I'll be towing a camping trailer with mine, to places I'll do moderate wheeling. But I'm thinking I will need to lift it and do front suspension mods both to better handle loads and provide better up-travel in the front.

Maybe 2" Mopar diesel lift (or AEV when available), adjustable shocks, and maybe a front hydraulic bump in place of an extended bump strike pad. And if necessary Timbrens in the rear if my trailer causes sag.

 

[Renegade]

So my 2-15/16 measurement seems consistent with your pre-lift estimate of 3" on your gasser. Depending on stock spring stiffness, the extra weight of the diesel might compress that remaining 3" on quicker than on a gas model.

This thread has been very good informationally for me and my planning as well. I really don't need/want much more lift, as I'll be towing a camping trailer with mine, to places I'll do moderate wheeling. But I'm thinking I will need to lift it and do front suspension mods both to better handle loads and provide better up-travel in the front.

Maybe 2" Mopar diesel lift (or AEV when available), adjustable shocks, and maybe a front hydraulic bump in place of an extended bump strike pad. And if necessary Timbrens in the rear if my trailer causes sag.

It is good that we got people some actual measurements to reference instead of taking wild guesses. It is not likely that the “wrong” springs were installed during assembly, but since this is the first year of diesel production, it could be that the stock springs may not end up being ideal for most uses. The stock front shocks are listed as having 7.88” of travel. If Jeep had allowed 40% of that as up travel, as is recommended by Accutune, the suspension would have 3.15” of up travel. The measurements here are fairly close to that mark (which may not have been the engineers’ actual target). I believe if I had a diesel Rubi that I wanted to keep almost entirely stock, I would consider adding a 3/4” spacer to the front.

 

[Renegade]

It is good that we got people some actual measurements to reference instead of taking wild guesses. It is not likely that the “wrong” springs were installed during assembly, but since this is the first year of diesel production, it could be that the stock springs may not end up being ideal for most uses. The stock front shocks are listed as having 7.88” of travel. If Jeep had allowed 40% of that as up travel, as is recommended by Accutune, the suspension would have 3.15” of up travel. The measurements here are fairly close to that mark (which may not have been the engineers’ actual target). I believe if I had a diesel Rubi that I wanted to keep almost entirely stock, I would consider adding a 3/4” spacer to the front.

(Sorry for quoting myself, but I screwed up posting)
I actually prefer the Teraflex 1” spacer, because it allows for the use of the indexed factory isolator.

 

[ScottLars]

I have had my 2021 Sport S diesel for a month now and around 900 miles. I can confirm the measurement of just short of 3". I have yet to experience any bottoming out though. Maybe I am babying it too much or simply don't have a similar undulation to find out.

 

[PackMule]

(Sorry for quoting myself, but I screwed up posting)
I actually prefer the Teraflex 1” spacer, because it allows for the use of the indexed factory isolator.

Yup, since spacers are so inexpensive, this might be good to try out first, see if it solves the bottoming problem, by giving up a little rake. Then see how my eventual towing/loading configuration works out in a couple months when my new camping trailer comes in, to determine if I need something more substantial.

Or.. i could just baby it until then. Not to say I'm hammering it to make it bottom. This thing would bottom out on a mall speedbump at 10mph... if I ever took it to a mall... nearest mall to me in western Montana is 60 miles... think I went there... once... but I digress.

... as I was saying, not that I'm doing high speed desert running. But I would like to do 20-30mph on a dirt road without worrying about hitting a medium sized pothole or rock.

 

[RedRockRider]

Casey250 on youtube has a bunch of videos of the JLRD he wheels. In one of the first videos with the new JL, he put a lift on it and noticed the bumpstop was different on the diesel. He suspected something hangs lower in the engine compartment, so Jeep modified the bumpstops for less up-travel to keep the axle from hitting. I'm not sure if he did further research, but it's worth checking out. It also seems like the stock Fox shocks are way too soft in both compression and rebound, at least my stock setup was.

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