Riding the Woops with Mojave and "Bottoming-Out"?

[joeym7]

Hello Folks,

I was Wheeling with 4 Wranglers (3 lifted, one stock) Sunday over the roughest terrain so far for this Newbie. Ton of fun, but I encountered behavior with my Mojave unique to me for the first time...We would hit the long series of "text-book" looking woops, very close each other, moderately deep maybe (apparently deeper than I thought anyway )...I can't say exactly how fast i was going, maybe 10-15 MPH when I hit them. At any rate, usually the first one or two where fine, but as the up and down momentum built up, after a couple, there was noise indicative of something bottomed out on the truck. It kind felt like shocks hitting a bump-stop, but I couldn't figure out how that could happen with the dual shock pairs set up on the Mojave? These woops weren't "that" extreme. (Obviously, when I slowed down just a hair no more bottoming out).

I asked the the Trail Guide who has been at this for 30 years and he didn't think it was the shocks but rather some part of the frame hitting the top of the woop I just went over. Possibly a skid plate or heat shield (he) offered.

So what do you guys think it was, shocks, frame, and if frame what section? (I'm going to get the creeper out later to take a look.)

Thanks Friends,
-Joe

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[CFLgladiator]

It was probably your jounce bump stops. Working as intended I imagine.

 

[Brojave22]

It was probably your jounce bump stops. Working as intended I imagine.

yep I agree, they sounds like your bottoming out but its just hitting the bump stop shocks, when i go slow in the sand i can hear them pretty loudly

 

[FLUndertaker]

Despite the marketing, it’s not a trophy truck. There’s only so much suspension and on whoops or heavy washboard, especially as some speed you will bottom it out.

 

[Joe Dillard]

It kind felt like shocks hitting a bump-stop, but I couldn't figure out how that could happen with the dual shock pairs set up on the Mojave?

What do you mean by dual shock pairs?

 

[KHam]

Since you're not going real fast, I would say the noise you're hearing is the front suspension bouncing off the hydraulic bump stops. I've added hydraulic bumps to my Rubicon and I go very fast through big bump areas in the sand. It's noisy when they're constantly engaging but never a harsh hit like with the factory bumps. I have aftermarket shocks and multi-rate springs (and 4-link rear) so they all work exceptionally well on big whoop bumps.

 

[obrianmcc]

Despite the marketing, it’s not a trophy truck. There’s only so much suspension and on whoops or heavy washboard, especially as some speed you will bottom it out.

I would agree with this ... the solid axle Mojave will never out perform an IFS Raptor or TRX (unless you are willing to dump a sh*t done more $$$). Simple physics are not on your side.

Next to that there is a whole book on suspension tuning. Terrain variable, spring rates, valving .. where is your rebound set? .. is your suspension packing up? .. the list goes on and on. Don't think for a second that any of these rigs are tuned off the show room floor to blast whoops.

 

[joeym7]

What do you mean by dual shock pairs?

Good question...I am no expert, not even a 1/4 expert ;-), but there are two shocks at every wheel...I always herd that Mojave has hydraulic bump stocks, which although I don't exactly know what that means would assume they are better than the average "bear" -see snippet from autoweek:

"The Mojave uses Fox's high-tech hydraulic bump stops, and the front springs are 1 inch taller and sport new spring mounts. A peek underneath the back end at the rear suspension."

S'why I was so surprised and thought (maybe) the old timer trail guide might have got it right that I was hitting something on the frame...

Can anyone explain what a "hydraulic" bump stop is vs a non-hydraulic bump stop?

thanks,

 

[joeym7]

Since you're not going real fast, I would say the noise you're hearing is the front suspension bouncing off the hydraulic bump stops. I've added hydraulic bumps to my Rubicon and I go very fast through big bump areas in the sand. It's noisy when they're constantly engaging but never a harsh hit like with the factory bumps. I have aftermarket shocks and multi-rate springs (and 4-link rear) so they all work exceptionally well on big whoop bumps.

Kham, What does the "hydraulic" imply in "hydraulic bump stops"?

Thanks in advance.

 

[Beemer533]

On the Mojave, only the front axle has the hydraulic bump stops, the rear has the standard style rubber or urethane.

A hydraulic bump stop is essentially a short shock where one end is free floating. The intention is that it allows the suspension to be dampened towards the end of the travel vs a more abrupt operation of a rubber/urethane style.

Take a look at this photo; the red and black bump stops are urethane and rubber respectively (except the one in the middle of the picture, that may have a spring, but I am not sure) The silver and black "shocks" are hydraulic stops.

These do operate like a shock; they are typically pressurized with nitrogen and the piston travels through oil.

 

[BlueScapegoat]

When you start seeing dents in the back of the cab a la Raptor you know you've gone too fast.

...or not fast enough.

Hope this is helpful.

 

[shokker70]

Can't answer any of your questions, but can tell you mine does the same. And on the road on intersections with deep dips. Takes most of them better than my girlfriends QX60, but definitely hear the 'thunk' in a couple of places.

 

[joeym7]

On the Mojave, only the front axle has the hydraulic bump stops, the rear has the standard style rubber or urethane.

A hydraulic bump stop is essentially a short shock where one end is free floating. The intention is that it allows the suspension to be dampened towards the end of the travel vs a more abrupt operation of a rubber/urethane style.

Take a look at this photo; the red and black bump stops are urethane and rubber respectively (except the one in the middle of the picture, that may have a spring, but I am not sure) The silver and black "shocks" are hydraulic stops.

These do operate like a shock; they are typically pressurized with nitrogen and the piston travels through oil.

Thanks so much Beemer, I "get it"...

With this understanding it is less certain what the cause is (to me that is)...I say this because the noise came only as my front hit the trough of the woops (not when the rear did) so one would think i wouldn't have heard such a "BUMP" (and one time it was quite-extreme) given the hydraulic stop. I do understand that these could bottom out too though, but I would hope in a less "dramatic" way...

I'm wondering if an alternative is likely, like my frame hit the top of the woops as the front came down (in the instances I hit the woops too fast)?

 

[Pescatoral Pursuit]

Next to that there is a whole book on suspension tuning. Terrain variable, spring rates, valving .. where is your rebound set? .. is your suspension packing up? .. the list goes on and on.

Where is this "book" you speak of?
Or heck I'd be happy with a YouTube link on setting up Jeep suspensions.

Anything's better than the "Hey! Put in this XYZ lift kit. It's the greatest! I called a couple mfrs and they were all pretty tight lipped about particulars. It was universally: "Oh yeah, our kit is perfect for that!"

 

[Beemer533]

Thanks so much Beemer, I "get it"...

With this understanding it is less certain what the cause is (to me that is)...I say this because the noise came only as my front hit the trough of the woops (not when the rear did) so one would think i wouldn't have heard such a "BUMP" (and one time it was quite-extreme) given the hydraulic stop. I do understand that these could bottom out too though, but I would hope in a less "dramatic" way...

I'm wondering if an alternative is likely, like my frame hit the top of the woops as the front came down (in the instances I hit the woops too fast)?

No problem at all.

My opinion, based on your description is that you were hitting front bump stops, possibly even bottoming them out. I haven't personally bottomed mine out (yet), so I can't really say what that "feels" like, but I think if you did actually hit the frame that would be fairly noticeable as the whole truck would kind of shudder.

Take a look underneath and see if there is any scraping marks on the frame or anything underneath. my bet is there isn't.

Here is another similar thread on the subject that may help: (1) Mojave bottoming out | Jeep Gladiator Forum - JeepGladiatorForum.com

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