bulldog-yota said:
Thai what is interesting is that everytime somebody makes a SUV without body on frame it actually weighs more than body on frame SUVs. Look at BMW and Porsche/VW for a mid size SUV vs the 4Runner or even the GX as an example. Maybe body on frame is still the way to go for SUVs.
True.
Unibodies are inherently stronger, especially in a crash test because it's all one structure (supporting each other)...in a BOF, you have to deal with the frame mounts which connects the body to the frame. Handling is better in unibodies...that is why X5 kills Mercedes ML.
However, for a unibody to off-road (torsional bending) and tow well, you have to reinforce it. A lot of the unibodies have frame rails (runs front to rear on both side of vehicle) and subframes (supporting front and rear suspension). They may also have half-boxed crossmembers (side to side).
In a cross-axle situation (ex: left front and right rear tires are in the air), most (if not all) unibodies bend, resulting in the inability to open/close your doors. (Most BOFs with a strong frame design avoid this pitfall.) Land Rover made a lot of effort to prevent this in the Range Rover thru heavily reinforcing the unibody. Thus, Range Rover weighs about 100 lbs heavier than the Lexus LX470 (an excellent BOF design).
On the other hand, for a BOF design to achieve on-road handling and safety, you need to also make the BODY strong and integrate it better with the frame (rather than just relying on frame mounts). A strong frame is a given. Thus, you have the Land Rover LR3. In the LR3, the body wraps around the frame to make it as integrated as possible (aka resemble unibody). Thus, you cannot easily see the frame when you peak under an LR3. Land Rover's design tries to mirror unibody's stiffness through a BOF design. The problem is...the LR3 weighs MORE than Range Rover and Lexus Lx470!! I need to remind you that the LR3 is smaller than both of these vehicles. This is not a good thing in this day and age when gas prices are climbing. (BTW, i do think that the LR3 is a better off-roader than RR due to BOF design and rear locker.)
For me, a Toyota BOF design is just right. It's perfect for off-roading (aka very strong), yet it crash tests very well (see IIHS rating for 4runner/GX). Weight is about right (not too heavy). Yes, real Toyota SUVs cannot hang with X5's on a canyon road, but who cares! SUVs are not sports car to begin with...it's all about capability and practicality for me! If i want a canyon-carver, then i would get a true sports car, not a poser.:bash: