RTT Concern - Top Heavy?

[Wotan]

Howdy. I got my RTT and put it together. Plan on putting it on top of the Gobi Stealth rack on my 2-door JK (2014) Rubicon this weekend.

Now, I am running with stock tires and suspension at the moment (and didn't really plan to lift anything, since to this point, I have always been able to negotiate all obstacles with good tire placement and line choice - I know, I know, I will eventually run into an obstacle I cannot negotiate, but we'll cross that bridge when we get there :) )

I have run into several situations with ruts, where I was pretty slanted going down the trail. Which has started to give me some pause... How much more prone to tip-over is the JK with the additional weight (and subsequent CG creep upwards) added to the top. I estimate that the rack plus RTT adds approx. 300lbs above the roofline?

Thanks!

 

[vegasjeepguy]

My 04 Rubicon is my daily driver and my biggest fear in life is rolling it by getting into an off camber situation. I chalk this up to seeing too many YouTube videos of Jeeps rolling down hills. I’m pretty sure I’ve never gotten close to tipping over, but it sure felt close a few times and, because of that, I have avoided putting anything on my roof.

Under normal driving conditions, even off-Road, this will probably never be an issue. The shorter wheel base of the 2DR raises the probabity ever so slightly. The key is just being aware and “if in doubt, don’t”.

 

[Wotan]

Yeah, Originally, I avoided anything over a 5-7deg slant - LOL. Over time, with slowly creeping up, I have become much more confident in the Jeep's ability to handle off-camber stuff; sure will need to go back to my original paranoia once the RTT is on top :) .

Thanks for the reply.

 

[vegasjeepguy]

I did have to get creative to find parking last night

 

[billum v2.0]

Like you, I have a 2dr JK. Center of gravity, off camber situations are major concerns as well. I looked at going exactly your route. The cost and production wait on the Gobi's, in combination with the center of gravity and garage clearance sent me in a different direction.
Keep this thread alive and post the day to day realities of living with your set-up, good and bad. I'm curious whether my fears were fueled by ignorant assumptions or solid reasoning.

 

[Wotan]

Like you, I have a 2dr JK. Center of gravity, off camber situations are major concerns as well. I looked at going exactly your route. The cost and production wait on the Gobi's, in combination with the center of gravity and garage clearance sent me in a different direction.
Keep this thread alive and post the day to day realities of living with your set-up, good and bad. I'm curious whether my fears were fueled by ignorant assumptions or solid reasoning.

Thanks "billum," will do.

Yeah, I used the Trail Duty folks to order my Stealth, they added a wind deflector and ladder for free. You are right, though, due to the hurricanes (or at least that was Gobi's reasoning...,) the rack was about 1 month delayed from the original delivery date. I did weight Ruby after installation, and the whole set up adds right around ~150# to the Jeep (using the optional sunroof tray is another 10#-15#, but I don't use it when the tent is on top.)

I have been looking for CG information on the Rubicon, but that's harder to find than a live mouse in a viper pit, so I pretty much have given up on 'estimating' impact. Suffice it to say that as long as the gravity vector from the CG stays (well) between the tires, it won't tip over. Clearly, it'll be back to the beginning with keeping the camber angles as small as possible, avoiding really slanted parts of the trail...

 

[Glenn]

It really is not a lot of extra weight and with trail time experience with it mounted you will eventually forget its even up there. Be mindful of it but now i am more worried about branch clearance than off camber...lol

 

[94Cruiser]

Or.... just get tires that are 2 inches wider..... that's adds more than one would think to off camber stability

Sent from my SM-G920T using OB Talk mobile app

 

[94Cruiser]

Or.....lol...... put Suburban axles under it

Sent from my SM-G920T using OB Talk mobile app

 

[billum v2.0]

Thanks "billum," will do.

Yeah, I used the Trail Duty folks to order my Stealth, they added a wind deflector and ladder for free. You are right, though, due to the hurricanes (or at least that was Gobi's reasoning...,) the rack was about 1 month delayed from the original delivery date. I did weight Ruby after installation, and the whole set up adds right around ~150# to the Jeep (using the optional sunroof tray is another 10#-15#, but I don't use it when the tent is on top.)

I have been looking for CG information on the Rubicon, but that's harder to find than a live mouse in a viper pit, so I pretty much have given up on 'estimating' impact. Suffice it to say that as long as the gravity vector from the CG stays (well) between the tires, it won't tip over. Clearly, it'll be back to the beginning with keeping the camber angles as small as possible, avoiding really slanted parts of the trail...

From your posts, reads like we have a similar take on avoidable risks. And if that assumption is correct, would you really put your trust in an engineering report conducted in sterile lab conditions as to just exactly where your risk of rollover falls on the X - Y axis? Me neither. I'm a belts and suspenders kind of guy and make no apologies. Interested in an actual experience of someone who listens to that little voice when it says "hmmm".
Subscribed.

 

[Wotan]

Or.... just get tires that are 2 inches wider..... that's adds more than one would think to off camber stability

Yeah, replacing the OEM 17" alloy wheels and tires with 16" steel wheels and tires that are wider/bigger (as long as they fit with OEM suspension/no lift) is a mod I was considering for 2018... Was thinking about something like this (was just checking on what's available and cost, not necessarily this specific combo)

 

[Wotan]

From your posts, reads like we have a similar take on avoidable risks. And if that assumption is correct, would you really put your trust in an engineering report conducted in sterile lab conditions as to just exactly where your risk of rollover falls on the X - Y axis? Me neither. I'm a belts and suspenders kind of guy and make no apologies. Interested in an actual experience of someone who listens to that little voice when it says "hmmm".
Subscribed.

Agreed. Then again, I am a MSc in THEORETICAL physics by education, even though haven't pursued a career in it :)... With this, I will go back to my original caution and "field-test" slowly. Adding a level back into the cockpit (added one in my original Wrangler 15+ years ago,) one of those used by 5th-wheelers to level the rig. Works nicely to get a feel for the actual lean angle, and provides consistency in testing ;)

 

[94Cruiser]

Yeah, replacing the OEM 17" alloy wheels and tires with 16" steel wheels and tires that are wider/bigger (as long as they fit with OEM suspension/no lift) is a mod I was considering for 2018... Was thinking about something like this (was just checking on what's available and costView attachment 40205 , not necessarily this specific combo)

As long as the 16's don't interfere with disc brakes...

I'd go with 15's on mine but they would rub the corner of my rear calipers... stock for mine are 16 which makes my tire selection not as good, because I don't want to go with 17's

Sent from my SM-G920T using OB Talk mobile app

 

[billum v2.0]

This is 17x9" ProComp wheels (4.5" backspacing) with LT305/65/17 tires, no lift. No rubbing lock to lock, but rough on fender flairs when stuffed. Mud terrain tires are loud and more work to keep balanced. My Procomp Xtreme MT2 tires were a particular problem to keep balanced, Nitto Trail Grappler's have been much better.
94 Cruiser's post about disk brake clearance is on point and why I went with 17".

 

[Hafaday]

The COG will change every time you add something to the vehicle.

http://www.jeepbbs.net/forums/showthread.php?t=1124
http://www.pirate4x4.com/forum/jeep-hardcore-tech/47834-how-calculate-your-jeeps-center-gravity-rollover-angles.html

 

[Wotan]

The COG will change every time you add something to the vehicle.

http://www.jeepbbs.net/forums/showthread.php?t=1124
http://www.pirate4x4.com/forum/jeep-hardcore-tech/47834-how-calculate-your-jeeps-center-gravity-rollover-angles.html

Yep. It will for sure :)

Thanks for posting these. Guess my inner scientist will be busy for a while now ;)

 

[Wotan]

This is 17x9" ProComp wheels (4.5" backspacing) with LT305/65/17 tires, no lift. No rubbing lock to lock, but rough on fender flairs when stuffed. Mud terrain tires are loud and more work to keep balanced. My Procomp Xtreme MT2 tires were a particular problem to keep balanced, Nitto Trail Grappler's have been much better.
94 Cruiser's post about disk brake clearance is on point and why I went with 17".

Hmmm... I thought the 16" wheels would work, since the ExtremeTerrain folks put them up as an option for the 2014 Rubicon - go figure. I know the M/T tires are a PITA when on regular roads, but I have been running on them for so long (on my first non-Rubicon Wrangler, I was running A/Ts, 15+ years ago), I cannot even imagine going back to A/Ts. I did have (more) issues on slick shelf roads with the A/Ts than the M/Ts, and, honestly, the last thing I want to (re-)experience is sliding on wet rock when there's a 3000+ ft dropoff less than 2ft from the tires :) Another issue when the Jeep is heavy is the lowest tire pressure you can use, so that could have an impact on off-roading as well. In any case, still only in the beginnings of researching potential tire mods, in no small reason due to the additional weight on top - a wide(er) stance will definitely help with camber issues...

As an aside, I love that EXACT 'intersection' in your picture - took both paths many a time, Blackbear to Telluride, then Imogene back; and Porphyry Gulch up to the lake (camped there in ground tent to catch sunset and sunrise.) Love that region - and so does the wife, although she prefers to lounge in Ridgway State Park while I explore and make photos :).

Also, I see you're in IA as well ("flyover country" many a year ago, I interviewed for a CSO position with the FAA, and the CIO made a comment along the lines of "ah, so you'r from flyover country; never understood why people would want to live where there are more cows than people" to which I responded, "That is EXACTLY why..." Needless to say, I did not get THAT job ;) .) I am on the Western edge, living in the Loess Hills. Maybe one of these days there might be an opportunity to meet up...

 

[Wotan]

View from Porphyry Gulch; Bullion King Lake behind me.

 

[billum v2.0]

View attachment 40212

View from Porphyry Gulch; Bullion King Lake behind me.

I know that spot...........The San Juan's are our favorite by a mile.
As to your argument for M/T vs A/T treads and description of traction/slickrock/shelf road drop offs..........this was without a doubt the single stupidest/arrogant decision I've made. If you look close at the previous picture at the signpost, you can see the snow just beginning to spit. First time to the area, overly motivated to notch that trail, ignorance, hubris all combined. The steps in the snow was a serious lack of judgment and push down of the "hmmmm". Lesson learned. The trip back on Imogene was all sun and vistas.
PM me if you know in advance you'll be in the DSM area with time for a sandwich/beverage, we're 10 minutes North and can meet with a little notice.
As to losing out on the job interview, I usually prefer bovine both as dinner as well as companions.

 

[Sparky]

I daily drove a 2-door jk for a number of years. I think long story short is that lifting the Jeep will have a much greater impact on cog then adding a rtt. That said, if you're considering a trail where rollovers are known to occur, I'd probably leave the rtt at home and bring a cot or ground tent. From the sounds of it though I think you'll be fine with an rtt.

If you haven't already, I'd consider looking into a long travel front sway bar like a Currie antirock. It greatly increases off-camber stability.. I actually sold the power disconnecting sway bar off my Rubicon in favor of the Currie.

If I kept my Jeep any longer I was going to have a proper roll cage installed, if anything for freeway rollovers cause the windshield frame on those doesn't hold up well in accidents. The never ending list of Jeep mods