What type of frame is currently used in most sedans?

[McBarrett]

Currently, most sedans adopt a unibody construction. The unibody does not have a separate frame; instead, the body itself serves as the mounting base for the engine and various chassis components, functioning as the frame while bearing all loads. Additional Information: Advantages and Disadvantages of Unibody Construction: 1. Advantages: 1. Lightweight with excellent overall bending and torsional rigidity. 2. Low cabin floor height, resulting in compact vehicle height dimensions. 3. Primarily uses sheet metal processing and spot welding, facilitating mass production. 2. Disadvantages: 1. Road and engine noise/vibrations are more easily transmitted into the cabin. 2. Since the entire body ensures structural rigidity, modifications are challenging.

[MacLondyn]

I've been driving for almost twenty years, and most sedans nowadays use unibody construction. This design integrates the entire body and chassis into one piece, like a hard-shell egg. The benefits are numerous: the body is dozens of kilograms lighter, making it very fuel-efficient in city driving; space utilization is excellent, with no more protruding frame rails in the rear floor; and the torsional rigidity of the body is strong during cornering, reducing the feeling of fishtailing. My Japanese car is a typical unibody design, and when I take my elderly parents out on weekends, they always say it feels much more stable than the old car with a separate frame from ten years ago. However, repairing this type of frame is a bit more troublesome. Recently, after a rear-end collision at the repair shop, the mechanic said that straightening the deformation takes more time compared to body-on-frame vehicles.

[NevaehDella]

A couple of days ago, I helped my young neighbor check out used cars and researched a lot about vehicle frames. Nowadays, most sedans on the street prefer using unibody construction, which essentially means eliminating the traditional chassis frame and welding stamped steel panels together to form an integrated structure. What impressed me most was the safety design: the crumple zones in the engine compartment absorb impact energy, and the A-pillars and B-pillars use ultra-high-strength steel. Last week, watching the C-IASI crash tests, all the high-scoring models were unibody. The downside is slightly weaker underbody protection, so you need to be careful on rough roads. For a young person's first car, I genuinely recommend this type—fuel-efficient, easy to drive, and with affordable parts.

[TylerDella]

The other day I was chatting with the owner at the auto repair shop, and he mentioned that nowadays nine out of ten sedans they repair use unibody construction. The beauty of this structure lies in material savings - stamping parts are assembled like Lego, reducing manufacturing costs by 30% compared to body-on-frame vehicles. The common MacPherson strut suspension is directly mounted to the body, improving shock absorption efficiency. However, the owner complained that repairs require using a frame straightener, and any deformation exceeding 3mm means replacing the entire assembly. He recommended owners install underbody protection against scrapes, since there's no separate chassis for protection. This design lowers the vehicle height by about 5cm, making entry and exit noticeably more convenient.

[MayaLynn]

As a mother of two, I pay the most attention to the car frame when choosing a vehicle. The salesperson mentioned that 90% of family sedans now use unibody construction, and the benefits are noticeable: the rear floor is completely flat, allowing my kids to stretch their legs after the car seats are installed; with reduced vehicle weight, fuel consumption is kept around 7L/100km, saving about 200 yuan on gas each month. Once during sudden braking on a rainy day, the stability control system intervened very quickly, which the salesperson explained was due to the lower center of gravity of this frame type. However, I should remind new moms that you can't stand on the trunk of a unibody car to close the tailgate like you can with an SUV, as the thinner sheet metal can easily dent. Most of the new sedans in our residential parking lot use this structure.

[SanQuinn]

I remember the first time I sat in a modern sedan, it felt like sitting in a bathtub. My cousin, who works as a car mechanic, said this is called a unibody frame, and currently eight out of ten sedans use this design. The core idea is to eliminate the heavy chassis frame and replace it with a cage-like structure made of high-strength steel beams. The biggest advantage is weight reduction—my colleague’s American car is 150 kg lighter than the old model, making acceleration noticeably quicker. The downside is limited modification potential, unlike body-on-frame designs that allow for easy chassis lifts. Once, while helping my cousin repair a crashed car, I saw door impact beams as thick as water bottles. He said this structure disperses collision forces across the entire body. For daily commuting, this type of car is definitely the right choice.