which is stronger? many Suv are made with unibody constuction these days. are they as strong as a ladder framed one? How about for towing?? Will a unibody strectch if used for towing freqently?

frame it

99% of people that drive SUVs never even drive on the grass so thats why many are unibody now. Its all about the ride, not utility.

If you are going to drive it like a SUV then look for a frame.

Bull.  The H1 is unibody.

I would worry more about the tow rating than construction.

4th Gen Toyota 4Runner is still a frame....

Quoted: Bull.  The H1 is unibody.

who told you that?

Jeep Grand Cherokees since 1990 or so have been unit bodies and no one who's ever offroaded one complains about it.

Most people stick to body-on-frame because they cling to the old familiar.  They do not understand how that "flimsy sheetmetal" can exceed the strength of a body on frame.

It is an easily verifiable fact that unit body construction is capable of achieving torsional and bending stiffnesses that a body-on-frame vehicle can't even dream of approaching.

As for towing, designing reinforcements into the unitbody to transfer and equalize a hitch's loads is a simple matter.

Nope,
 The H1 is just like our Mil HMMVS. it has a frame.

FREE

Quoted: Bull.  The H1 is unibody.

Unibody is for cars, frames are for trucks.
Hell, frames are for cars too.

Quoted: Jeep Grand Cherokees since 1990 or so have been unit bodies and no one who's ever offroaded one complains about it..

but the serious one run subframe connectors

Frame = truck based vehicle, which makes it more durable.

Unibody = car based and generally not as "tough."

Nobody takes SUVs off road anyway so it probably won't make much of a difference to 99% of people.

Not all unibodies are car based.^^^

Quoted: Quoted: Bull.  The H1 is unibody. who told you that? www.off-road.pl/temp/HummerChassis.jpg

That thing is so sweet.. Look at the ground clearance.  I wish I could afford a surplus and put a powerstroke in it.

Quoted: Frame = truck based vehicle, which makes it more durable. Unibody = car based and generally not as "tough." Nobody takes SUVs off road anyway so it probably won't make much of a difference to 99% of people.

Another one who reads too much "Four Wheeler".  Are you an engineer, and do you work in the suto industry?

Quoted: Unibody is for cars, frames are for trucks. Hell, frames are for cars too.

I'm sure you could teach the engineers of all the world's premier automakers a thing or two, with your PhD in mechanical engineering and decades of experience in vehicle design.  Right?

Quoted: Not all unibodies are car based.^^^

You're correct.  I can't think of a unibody design that is truck based either.  Generally truck based vehicles are tougher.  I'm guilty of over simplifying.  

We will seam/stitch weld car bodies for rally duty, but it's a major PITA!!

But, then again, we also chuck a full cage in there, so it's basically got a frame by the
time I'm done with it...

Quoted: Another one who reads too much "Four Wheeler".  Are you an engineer, and do you work in the suto industry?

I don't work in the SUTO industry or the auto industry.  I was offering my humble opinion....lighten up Francis.

Quoted: I can't think of a unibody design that is truck based either.

Does this one ring a bell?

Quoted: Quoted: I can't think of a unibody design that is truck based either. Does this one ring a bell? www.off-road.com/jeep/grand/rubicon/tourbus10-97.jpg

What truck platform was the Grand Cherokee based on since you seem to be the resident fucking expert?

Quoted: Quoted: I can't think of a unibody design that is truck based either. Does this one ring a bell? www.off-road.com/jeep/grand/rubicon/tourbus10-97.jpg

My 98 Pathfinder is the same way I think.

Quoted: Quoted: Quoted: I can't think of a unibody design that is truck based either. Does this one ring a bell? www.off-road.com/jeep/grand/rubicon/tourbus10-97.jpg What truck platform was the Grand Cherokee based on since you seem to be the resident fucking expert?

It was designed FROM THE GROUND UP to be a UNIT BODY OFFROAD TRUCK.  Do you think that everything on the road is derived from something else?

Go back to reading Four Wheeler.  

Way too much is made of this debate.   Hard core off roaders, load carriers, tow vehicles, and 'standard' pickup trucks are the only vehicles who currently need a frame.  In theory, a unibody could be made to perform in these applications, but the weight of the thicker/more numerous sheet metal parts would even make the frame attractive.

Unibodies exist for two noble reasons, stiffness and weight savings (they can also crumple at a pre determined rate in wrecks).  Mass production makes them economical to produce as well.  A standard pickup needs a frame because the bed/cab transition of the design wouldn't allow a strong enough 'cage'.  The honda ridgeline is the only one that doesn't have the 'seam' between the cab and bed and it gets around it by having those MASSIVE pillars aft of the cab.  Even then, it's only a 1/2 unibody vehicle, and not what you call typical.  A typical SUV (not used for heavy towing) could easily get by as 100% unibody as the roof extends all the way to the back.

Look at it this way, unibodies are superior in vehicles that experience predictable, reasonably light loads.  If you exceed the strength limit in one place on the body, the structure as a whole can begin to fail.  Frames can take severe point pressure that unibodies cannot.  A frame will also flex, which depending on your application may be a good or bad thing.  Climing on a rock, good thing...  Driving over uneven roads, a bad thing.  I had a C4 Vette and you couldn't put the top back on unless parked on level ground because the body flex would cause the distance between the windshield mounts and the rear structure to change enough so the holes wouldn't line up.

IMO, many just don't like the thought of them in trucks because they would come with a whole host of other modern goodies like IFS/IRS that give good old boys who like to jack things up the hives.  Most of the good old boys I grew up with who frown on SUVs and yuppies are just as guilty of driving their truck on the road 100% of the time.  The mudholes were only in their dreams...

A vehicle is a tool, just like a wrench.  Select the proper tool for the proper job.

Quoted: It was designed FROM THE GROUND UP to be a UNIT BODY OFFROAD TRUCK.  Do you think that everything on the road is derived from something else? Go back to reading Four Wheeler.

Most unibody vehicles are passenger cars and not "trucks".  Again I was generalizing.  It wasn't necessary to nit-pick the hell out of me.  BTW I owned a new 99 JGC, and it spent almost as much time in the shop as it did on the road.  

Quoted: Quoted: Unibody is for cars, frames are for trucks. Hell, frames are for cars too. I'm sure you could teach the engineers of all the world's premier automakers a thing or two, with your PhD in mechanical engineering and decades of experience in vehicle design.  Right?

Wow... just wow.

Any idiot could tell you the reason today's cars are all unibodies is for one reason.  It's cheaper.  There's a reason Ford still puts their flagship luxury car on a frame, GM did it too until 1996, when they decided to kill it off to make more SUVs.  A frame is ideal for multiple platform flexiblilty in addition to added strength.  You'll also never see a cop ram someone with his FWD econobox "Impala" for one reason... it's a unibody.
You also get one more cushion between you and the road.

How fucking ignorant to get so bent over peoples OPINIONS!  I do believe the original poster was simply asking for OPINIONS, not the actual designers official thought pattern behind it.

The Jeep Cherokee and Grand Cherokee are both unibody, as stated previously, but any hard core off roader will strengthen the unibody with sub frame connectors and a complete roll cage. Even then the unibody jeeps will suffer from body flex, and will eventually break in half if let go that long.

Look at any unibody jeep that is wheeled very hard, not mall crawled, but actual rock and trail running, the door gaps will be way off due to all the twisting motion of the frame.


EDIT: You would think after three proof reads I would have gotten all the spelling fixed..grr

That's not to say a frame will protect the body from any twisting or cracking.  The body provides a significant ammount of ridgidity to the whole vehicle too.

It all depends on what you're using the thing for, though, I'd always say go with a frame just for the ride quality.  Yeah, german cars are nice and tight, but you'll blow your load when you jump into a full-sized car with a frame.  At least until you modify it beyond reason... then you move to Michigan and kick yourself for taking Ohio's roads for granted... err, maybe that's just me.

Oh, and by the way, Michigan's roads blow ass.

Quoted: which is stronger? many Suv are made with unibody constuction these days. are they as strong as a ladder framed one? How about for towing?? Will a unibody strectch if used for towing freqently?

Any SUV that has a higher tow rating, such as the Excursion, Suburban, & Tahoe has a full frame, and are based on a pickup truck chassis.  If you dont plan on towing less then 5000 pounds, a unibody SUV will work fine. When looking at vehicles, just look at the max trailer weight the vehicle can tow, if what you need to pull is within that range, the vehicle will be perfectly fine.

Quoted: Quoted: which is stronger? many Suv are made with unibody constuction these days. are they as strong as a ladder framed one? How about for towing?? Will a unibody strectch if used for towing freqently? Any SUV that has a higher tow rating, such as the Excursion, Suburban, & Tahoe has a full frame, and are based on a pickup truck chassis.  If you dont plan on towing less thenmore than 5000 pounds, a unibody SUV will work fine. When looking at vehicles, just look at the max trailer weight the vehicle can tow, if what you need to pull is within that range, the vehicle will be perfectly fine.

Yeah, you're right.  And the part that sucks is you can't get an SUV that has a frame and doesn't ride like a full-sized truck (Though, I know, that's the point of the full-sized SUVs).  My friend's Tahoe is nice, but that thing's ride is pretty rough, and when it's towing, I'd rather go sit on that mechanical horse outside the grocery store.

In the real world... you have to put the commercials out of your mind.  You're not going to drive to the top of a mountain and park on the top after flying through giant mud-pits just to go camping.
You're going to be like every other soccer-mom, driving through the city, and the only "off-roading" you'll do will be when the road is covered with snow, or your driveway is gravel.
Though, if you do actually use your SUV as an SUV... you're probably driving something at least 5 years old, and you're part of a very small percentage.

I swear, it's hopeless trying to talk all my preppy-ass friends to drive their "Sport Utility Vehicles" off-roading.  Arg, these pussies piss me off... going out spending all that money on 4WD and all that bullshit, and they don't even have the balls to take it off the pavement for fear of getting it muddy.

/end rant.

maybe its just me, but i much prefer body work on a frame and panel vehicle. for an suv, i consider that a significanr advantage.