Kaderabek
GOLD Star
Just make sure you don't get your "moment arm" stuck under the truck when it rolls.... 
TJK
TJK
Center of grav. with roof rack
- Thread starter Trunk Monkey
- Start date
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I'm running 4 78" load bars with Yakima A Towers. Fully loaded with 2 kayaks, Rooftop tent and awning I can definitely feel the difference. Even with just the Rooftop tent, which weighs in at about 115lbs., give or take, there is more sway. I'm running 850/863 OMEs, and usually carry an additional 150lbs of gear in the back on a daily basis.
I wouldn't do any real crawling with that weight up top without being REALLY careful. I do not, if I can help it, carry spare tires or gas on the roof, but try to keep relatively lightweight items up top.
-H-
I wouldn't do any real crawling with that weight up top without being REALLY careful. I do not, if I can help it, carry spare tires or gas on the roof, but try to keep relatively lightweight items up top.
-H-
Kaderabek
GOLD Star
Well, haven't 100% figured that one out yet either. Late for my daughter's ballet recital (or was it mine...?), should have never been wheeling that morning, hit the Saturday GSMTR traffic jam, eventually needed to put the hammer down and make some time. The somewhat big hole on the passenger side of the truck (behind the truck in the photo) had been made much deeper by rain the night before. Front passenger side wheel went in, rear driver's wheel started to come up, and unlike the day before continued to come up. It was hysterical, I literally had time to turn to the passenger and says "Ah s***...." Then bang, the 55 was taking a little nap. Whoops....
Junk said:
Well the above scenario would move the overall COG up about 2 inches. For a 5200 pound rig, it'd be closer to 2 1/2"... making some questimates of the stock COG of course.
The net effect would probably be comparable to 3 to 3 1/2" lift. Donno... is that negligible??
Rookie2
Eric:
Man that is one-ugly-booty-fab-set-up you have there my friend
- have you thought of putting in some decking so you have storage under the dog cages (like mine) it does wonders and gets the dogs up to the height so they can look out the window/feel the breeze.
I'm also in the camp of a very light set-up on the roof (~15-20lbs on racks and ~40lbs on a thule top box). Stuff stays dry, much more aerodynamic, flexibility of carrying other stuff (canoes, bikes, lumber), etc.
I'm also calling BS on those that say they don't notice the load of a heavy system with a bunch-o-crap-on-it (Eric!) - you will notice milage change, more tippy, prone to cross-winds, more noise, etc.
I'm with Doug - I love the look, but it just doesn't make sense for my application(s)
Cheers, Hugh
Man that is one-ugly-booty-fab-set-up you have there my friend
- have you thought of putting in some decking so you have storage under the dog cages (like mine) it does wonders and gets the dogs up to the height so they can look out the window/feel the breeze.I'm also in the camp of a very light set-up on the roof (~15-20lbs on racks and ~40lbs on a thule top box). Stuff stays dry, much more aerodynamic, flexibility of carrying other stuff (canoes, bikes, lumber), etc.
I'm also calling BS on those that say they don't notice the load of a heavy system with a bunch-o-crap-on-it (Eric!) - you will notice milage change, more tippy, prone to cross-winds, more noise, etc.
I'm with Doug - I love the look, but it just doesn't make sense for my application(s)
Cheers, Hugh
I have a alloy surco rack and I take a 1-2mpg hit from using it- and it's a pretty low-profile rack. I can feel the difference at freeway speeds when first put on, then you get used to it and don't notice it anymore.
It does have bling-factor but I only put it on when I need it now.
I'm going on a road trip soon and I'm considering a hitch rack for MPG reasons- I'd rather avg. 23-25mpg rather than tickling the teens on a long trip.
It does have bling-factor but I only put it on when I need it now.
I'm going on a road trip soon and I'm considering a hitch rack for MPG reasons- I'd rather avg. 23-25mpg rather than tickling the teens on a long trip.
Trunk Monkey
Moderator
- Thread starter
- #30
FirstToy said:
You can't be talking about an 80.
FZJFillmore said:
you don't have fuel magnets?
CDN_Cruiser said:Eric:
Man that is one-ugly-booty-fab-set-up you have there my friend
I'm also in the camp of a very light set-up on the roof (~15-20lbs on racks and ~40lbs on a thule top box). Stuff stays dry, much more aerodynamic, flexibility of carrying other stuff (canoes, bikes, lumber), etc.
I'm also calling BS on those that say they don't notice the load of a heavy system with a bunch-o-crap-on-it (Eric!) - you will notice milage change, more tippy, prone to cross-winds, more noise, etc.
I'm with Doug - I love the look, but it just doesn't make sense for my application(s)
Cheers, Hugh
hey hugh -- ouch! Where did you get your decking from? I have to actually keep the crates covered usually, since my one pit bull, Precious, barks and squeals at everything that passes us -- she gets very worked up by passers-by --
-- and also, I'm cruising betw. 70-80 on the highway with my 3FE and I honestly don't hear or feel a thing -- it's been a while since I drove my '94 though, and when I do drive it, it's like driving an entirely different vehicle --
e
Trunk Monkey
Moderator
- Thread starter
- #33
Junk said:you don't have fuel magnets?
Fawk, I'd magnetize the whole damn truck if I'd get better mileage.
FZJFillmore said:
No, I have a 4x4 4Runner.
Here is my avg. from a recent trip to AZ at 65mph (although the temp. was the most notable thing!)
If I bump up to 75mph and do alot of semi-truck passing, my avg went down to about 23.6mpg- (the computer is about 2mpg optimistic most of the time)
With roof rack and off-road tires, it's hard to go better than 21-23mpg
FirstToy said:No, I have a 4x4 4Runner.
Here is my avg. from a recent trip to AZ at 65mph (although the temp. was the most notable thing!)
If I bump up to 75mph and do alot of semi-truck passing, my avg went down to about 23.6mpg- (the computer is about 2mpg optimistic most of the time)
With roof rack and off-road tires, it's hard to go better than 21-23mpg
is it a 4-cyl?
hehe --
erics_bruisers said:
which mountain range is that coming down from? If you didn't include the "highway" part I thought you were referring to its terminal velocity...
actual thread content - I believe it is not only the COG that is at issue but the distribution of mass about that COG and perturbations to substantial quantities of that mass distribution. Most folks have seen a single person capable of keeping truck from rolling on an off-camber trail with just one hand and by the same token, having a bunch of extra mass at the edge of your COG will allow a slight perturbation to roll it. Bottom line is there's way too much physics involved with a comparison of even a single vehicle under differing conditions let alone to compare separate vehicles. But I would argue that you should have as much of your mass centralized as close to your COG and have that COG as low as possible if your goal is not to roll. Oh, and articulation is good - I think..
Mike R.
Very well put, makes you think before you strap a bunch of crap up there.
FZJFillmore said:
Don't worry about Colorado 2000' dropoffs and a roof rack. The ledge roads that have these dropoffs can be narrow, but they are never severely off camber with maybe a couple of notable exceptions (I'd be more concerned about the size of the FZJ80 than a roof rack).
For a long wheelbase rig like a FZJ80 with a nice wide track width, it's going to take 40 degrees plus of off-camber angle or a severe screwup that has nothing to do with COG in order to roll. Plus, the propensity to roll has to do with a lot of factors way beyond COG - you need to get into link geometry (roll axis) and a bunch of other stuff before assuming the simple addition of a roof rack is going to make a fullsize rig roll-prone.
For frame of reference, I'm a newbie looking for a FZJ80 to replace my 8" lifted Jeep Cherokee (XJ). Child number four is on the way, so the Jeep has to go. I have a roof rack on my XJ, and while not 200 lbs, I do carry my spare up there for wheeling and that is a good 160 lbs total weight. This is on a 101" wheelbase and 2" narrower track width than a FZJ80 with a COG that is way worse than a typical OME lifted FZJ80. I never even think about it offroad and probably run some more hardcore stuff than you are planning (all the fun is at the lower elevations).
I'd keep the weight down, but that's mostly because the FZJ80 is a pig out of the box, not because of COG. Adding eight hundred pounds of excess weight ( heavy duty rack and bumpers) is probably not the best thing for those who aspire to rock crawl. I'll go as light as possible up top and tube for the bumpers.
Really, if the rack was that big of a deal, you wouldn't be able to wheel with a bunch of passengers. I mean, would strapping 200 lbs of Ted up top really be worse than 4 Teds as passengers?
Nay
