Body on Frame vs Monocoque SUV's

Monocoque or Unibody frame SUV’s are the talk of the town in the auto industry these days. Although this frame construction was considered to be better suited for sedans and hatchbacks, it is slowly creeping its way into the genre of bigger vehicles. However, despite the fact that monocoque frames are more technologically advanced, some manufacturers still adopt the traditional Body on Frame or Ladder Frame construction for some of their vehicles. In this article, we will understand the basics behind both and address the advantages they have over each other to assess which of them is superior. So without any further ado, let’s commence the battle of Body on Frame vs Monocoque SUV’s.

The Fundamentals:

Before we start the battle, let’s have a brief overview of the two competitors first. The Body on Frame construction dates all the way back to when the first cars arose in the 19^th century. This construction essentially consists of two major components, a rigid ladder-like frame network that carries the engine and drivetrain and a separate body construction that is mounted on it.

The Monocoque Frame, on the other hand, has a unitized frame and body construction. Here the entire frame network bears the load of the vehicle’s components unlike the Body on Frame Construction where only the ladder section takes the brunt.

Body on Frame vs Monocoque SUV's: Advantages of Monocoque Frames

1. Light and Fuel Efficient:

The prime benefit of a monocoque construction is that its lightweight. Since the frame network expands to almost every bit of the car, the necessity of adding extra mass to a selective portion for strength is eliminated. This ensures that the vehicle is much lighter in comparison to that with a  body on frame construction. As the overall load to be hauled is lesser, a smaller capacity engine can be incorporated to accomplish the same task. This directly translates to better fuel economy.

2. Better Ride Dynamics:

A monocoque construction will always have better handling and performance compared to a body on frame construction. The floor pan can be placed much lower on a monocoque construction, giving the vehicle a lower centre of gravity. This allows the vehicle to be agiler in terms of handling. The lightweight factor which contributes to better fuel economy also gives it much better outright performance. The low floor placement also makes a monocoque construction much easier to get in and out of.

3. Higher Safety:

A lot of R&D resources go into the manufacture of monocoque frame networks. The frame is constructed in a way that it crumbles and bends only in specific ways. While designing the frame networks, manufacturers use this quality to ensure that the impact force of the crash is diverted away from the vehicle’s occupants. Since the frame is also more expansive in terms of area covered, the vehicle can resist impacts from various directions without giving in easily. This contributes to a higher safety factor in monocoque constructions.

Body on Frame vs Monocoque SUV's: Advantages of Body on Frame

1. Perfect Off-Roaders: 

Despite being more than a 100 years old, the technology of body on frames can literally exist solely for its off-road prowess. The super toughened frame structure of these vehicles can gobble up rocks, uneven terrain, and almost anything you throw at them like child’s play. Body on frame constructions are obligated to have higher floor pans due to their construction. This allows for much higher ground clearance which is a complete boon for tackling off-road duties.

2. High Torsional Rigidity:

A body on frame chassis has a very high resistance to bending and deformation under stress. Torsion and bending resistance represent the amount of force required to twist or extend the chassis member by a certain amount of degrees or centimetres. In the case of a body on frame construction, the force required to significantly bend and deform the chassis is very high and almost impossible to attain in practical applications. If you intend on ever towing heavy objects with your SUV, it will certainly be advisable to choose a one which has a body on frame construction as a monocoque construction could very much give in and deform during the same.

3. Easy to Repair:  

Since the frame and body are two different elements in the body on frame construction, any damage caused would be much easier to repair due to the isolated components. Damage to a monocoque construction would probably require the entire chassis unit to be replaced, which is an expensive ordeal. The body on frame construction is the oldest kind of chassis construction known to the automotive world. It’s almost been used for over a century. So in case you do get into any trouble during your off-road escapades, even an average roadside mechanic should be able to easily identify and diagnose the problem.

Body on Frame vs Monocoque SUV's:  The Conclusion

Both the Monocoque and Body on Frame construction have their fair share of pros and cons. They are pretty much like apples and oranges. One is more suited for the road while the other is a better performer off-road which SUV’s are actually intended for. But let’s admit it, nowadays most cars only spend their time on the asphalt rather than off it. While there’s no doubt that a body on frame will have the upper hand in utilitarian tasks, monocoque construction are evolving rapidly with time.  All Land Rovers these days use the monocoque frame construction and their off-road capabilities are almost unmatched. While some manufacturers still do put to use the body on frame construction occasionally, the victor of this battle is the monocoque construction taking into consideration the holistic overview.