Experienced drivers often recall “unkillable” VAZ-2106 or Mercedes W123, the bodies of which could stand for decades without rust, and in case of an accident they “repelled” blows like a tank. Modern cars seem fragile: a slight blow is enough and there is a dent or even a crack on the bumper. Hence the common myth: “Cars used to be made of metal, but now they’re made of foil!”. But is this really so? And why do engineers deliberately choose soft steels for bodies?

In fact, the “softness” of modern bodies is not a reduction in cost, but the result of complex engineering compromises. Automakers do not skimp on materials, but follow physics, economics and safety requirements. Yes, body Toyota Camry 2023 is indeed more easily deformed upon impact than Volvo 240 1985, but that doesn't mean it's worse. They just have different tasks: if old cars were designed to “survive” in a head-on collision at a speed of 60 km/h, then modern ones are designed to survive energy absorption at 90+ km/h with minimal risk to passengers.

In this article we will look at:

- What kind of metals are used in the automotive industry today (spoiler: it’s not “tin” or aluminum foil).

- Why is metal soft? saves lives in an accident - a paradox that contradicts everyday logic.

- How the “softness” of the body is related to weight, fuel consumption and even the price of insurance.

- Why repairs of modern cars are more expensive, and how this is related to the material of the body.

And most importantly: we will answer the question that worries everyone - Is it possible to make the body “tougher” without sacrificing safety?, and why don’t even premium brands like Mercedes or BMW.

1. What metal is used in modern bodies: debunking the myth about “foil”

The first misconception: modern bodies are made of “thin iron” or aluminum foil. In fact, the automotive industry uses high strength low alloy steels (HSLA), dual-phase steels (DP) and boron steels - materials that are superior in strength to Soviet St3 (bodies were made from it Lada). But their structure arranged differently.

Key difference - ratio of strength and ductility. Old bodies were made from tough but fragile steels (for example, 08YU or 08kp), which did not crumple upon impact, but broke. Modern steels, on the contrary, deform in a controlled manner - this is inherent in their microstructure. For example, boron steel (used in Volvo XC90 and Ford F-150) has a tensile strength of up to 1500 MPa, but can stretch 10–15% before breaking. For comparison: steel Lada had a strength of ~300 MPa and stretched by only 2–3%.

  • 🔹 HSLA (High-Strength Low-Alloy) — steel with additions of manganese and silicon. Used for load-bearing elements (spars, struts). Strength: 350–700 MPa.
  • 🔹 DP (Dual-Phase) — two-phase steels with a ferrite-martensite structure. Used in areas of controlled deformation (front/rear bumper). Strength: 500–1200 MPa.
  • 🔹 Boron steels — for the most loaded areas (thresholds, central pillar). Strength: up to 1500 MPa, but at the same time they not fragile thanks to heat treatment.
  • 🔹 Aluminum alloys - used in premium models (Audi A8, Jaguar XJ) for weight loss. The strength is lower than that of steels, but the weight is 30–40% less.

Thus, the “softness” of the body is not the weakness of the material, but its ability to absorb energy. For example, in a frontal impact, the front side member is made of DP steel collapses like an accordion, dissipating kinetic energy and reducing the load on the interior. Hard steel Lada in the same situation it would simply transfer the blow to the passengers.

📊 Which body do you think is more reliable?
Hard like old cars
Soft, but safe, like modern ones
Aluminum (lightweight, but expensive to repair)
I don't know, I never thought about it

2. Physics of accidents: why soft metal saves lives

The main argument against “soft” bodies: “Before, the car drove on after an accident, but now it’s scrapped”. But this is like comparing a tank and a modern body armor: the tank will withstand a shell hit, but the crew may die from overloads. The main thing in a car is save the lives of passengers, not the body.

There are three key factors at play in a collision:

  1. Impulse force — the stiffer the body, the greater the acceleration (overload) passengers experience. For example, in an impact at 60 km/h, a rigid body will transfer a force of 30–40g, which is fraught with injuries to internal organs. The soft body stretches the impact over time, reducing the overload to 15–20g.
  2. Deformation zones - modern cars are designed so that the front and rear parts are crushed, but the interior remains intact. For example, in Volvo S90 the front part of the body absorbs up to 70% impact energy.
  3. Secondary strikes - If the body does not deform, passengers can be injured by hitting the steering wheel, dashboard, or even each other. The soft body dampens inertia.

Example from crash tests: Mercedes-Benz W124 (1980s) and Mercedes-Benz C-Class W205 (2010s) with a frontal impact at 64 km/h:

Parameter W124 (hard body) W205 (soft body)
Front deformation Minimum (20–30 cm) Significant (50–70 cm)
Overload on mannequins 35–45g 18–22g
Risk of head injuries High (hitting the steering wheel) Low (cushions + deformation)
Maintainability High (can be straightened) Low (requires replacement of elements)

Critical Information: Modern bodies are designed to one-time energy absorption. After a serious accident, they cannot be “straightened” - this will disrupt the structure of the metal and make the car dangerous. Therefore, insurance companies often write off cars even after minor accidents.

💡

If you buy a used car after an accident, check not only the external damage, but also the geometry of the body on the stand. Even a slight displacement of the side members by 5–10 mm can lead to uneven tire wear and poor handling.

3. Weight, savings and ecology: why every kilogram counts

Second myth: “Manufacturers save on metal, so they make bodies thinner”. In fact, the thickness of the body sheets has hardly changed over 30 years (0.7–1.2 mm for most models), but their composition and distribution became different. The main reason is struggle for weight.

Every kilogram saved gives:

  • 🚗 Reduced fuel consumption — for every 100 kg of weight there is ~0.3–0.5 l/100 km. For example, Ford F-150 after switching to an aluminum body in 2015, it became 300 kg lighter, which resulted in savings of up to 1.5 l/100 km.
  • 💨 Reduced CO₂ emissions - European standards Euro 6/7 strictly regulate environmental friendliness. Lightening the body by 100 kg reduces emissions by ~10 g/km.
  • 🔋 Increasing the range of electric vehicles - in Tesla Model 3 aluminum body weighs 20% less than steel, which adds up to 50 km run on one charge.
  • 💰 Tax savings - in some countries (for example, Japan), car tax depends on weight. A lighter car is cheaper.

However, “relief” does not mean a deterioration in security. For example, BMW 5 Series (G30) 100 kg lighter than its predecessor, but received 5 stars Euro NCAP thanks to the use of high-strength steels in critical areas.Secret

Why don't premium brands make titanium bodies?

Titanium is stronger than steel and lighter, but its processing requires special equipment and is 5–10 times more expensive. For example, a titanium body for Mercedes S-Class would increase its price by ~$50,000. In addition, titanium is difficult to weld using traditional methods, which complicates mass production.

One more nuance - weight distribution. Modern bodies are designed so that the bulk of the weight falls on the lower part (sills, floor), which improves handling. For example, in Mazda CX-5 use ring structure of the body, where the load is evenly distributed around the perimeter and is not concentrated at one point.

4. Repair of modern bodies: why is it more expensive and more difficult?

The main disadvantage of “soft” bodies is high cost of repairs. If on VAZ-2107 it was possible to straighten the dent with a hammer, then Audi A4 B9 After an impact, the entire panel often needs to be replaced. Why?

Reasons:

  1. High-strength steels cannot be straightened — if the deformation exceeds 3–5%, the metal loses strength. For example, a spar from boron steel after an impact you cannot “pull it out” - it is only replaced.
  2. Complex panel shapes - modern bodies have multi-beam structure with stiffening ribs. For example, the hood Toyota RAV4 has 8–10 “waves” that cannot be restored without factory equipment.
  3. Use of adhesives and laser welding - in Volvo XC60 up to 30% of body joints are made with glue (rather than welding), which complicates disassembly.
  4. Manufacturers' requirements - many brands (for example, Mercedes) prohibit body repairs without original spare parts, otherwise the warranty will be voided.

Comparison of repair costs after an accident (frontal impact at 15 km/h):

Model Body type Repair cost (RUB) Reason
VAZ-2110 (1995) Steel 08YU, 0.9 mm 15 000–25 000 Straightening + painting
Toyota Corolla E210 (2020) HSLA + DP steel, 0.7–1.1 mm 80 000–120 000 Replacing the bumper + side member
Audi A4 B9 (2016) Aluminum + borstal 200 000–350 000 Replacement of aluminum panel + adhesive connection
⚠️ Attention: If, after an accident, you are offered “cheap” body repairs using non-original spare parts or welding instead of glue, refuse. This may lead to corrosion at joints (due to galvanic incompatibility of metals) or loss of body rigidity on the next hit.

Originality of spare parts (numbers must match VIN)

Connection method (welding, glue, rivets - must be the same as the manufacturer)

Body geometry (checked at the stand)

Warranty on work (at least 12 months)

Cost of painting (must include anti-corrosion treatment) -->

5. Corrosion: why modern bodies rust faster

Another complaint about modern cars: “Before, the bodies did not rust for 20 years, but now after 5 years they are already saffron milk caps”. There is some truth here, but the reason is not “bad metal”, but changes in protection technologies and operating conditions.

Factors accelerating corrosion:

  • 🔥 Thin layers of zinc - if in VAZ-2106 the body was hot galvanized (layer 10–15 microns), but is now often used electrolytic galvanizing (layer 5–7 µm). It is cheaper, but less resistant to chips.
  • 🌧️ Eco-friendly primers - modern LADA and Renault They use water-soluble primers (without lead), which are less resistant to moisture than old epoxy primers.
  • 🚗 Hidden cavities - modern bodies have a lot of “pockets” (for example, in the sills Kia Rio), where water and dirt get in, but the drain holes often become clogged.
  • 🧂 Reagents on the roads — magnesium and calcium chlorides, which are sprinkled on roads in winter, accelerate the corrosion of aluminum and high-strength steels by 3–5 times.

At the same time, some manufacturers make bodies fully galvanized even today. For example:

  • 🔹 Volkswagen Passat B8 — 100% galvanized body with a guarantee against through corrosion for 12 years.
  • 🔹 Skoda Octavia A8 — galvanizing + additional waxing.
  • 🔹 Toyota Camry XV70 — electrozinc plating + 7 layers of protection.
⚠️ Attention: if you are buying a machine for use in coastal regions (Sochi, Vladivostok) or in cities with active use of reagents (Moscow, St. Petersburg), choose models with full galvanized body (the list is on the manufacturer's website). Aluminum bodies (Audi A8, Jaguar XE) in such conditions corrode faster than steel!

6. Is it possible to make the body more rigid without losing safety?

Theoretically yes, but in practice it is unprofitable or impossible. Here's why:

Option 1: Increase the thickness of the metal

If you make a body from steel with a thickness of 1.5–2 mm (like UAZ Patriot), it will become 200–300 kg heavier. This will lead to:

  • ➕ Improved protection in minor accidents (dents instead of cracks).
  • ➖ Increased fuel consumption by 1–1.5 l/100 km.
  • ➖ Deterioration in controllability (a heavier car slows down and turns worse).
  • ➖ Price increase by 5–10% due to additional metal.

Option 2: Use titanium or carbon fiber

Carbon fiber is 4 times lighter than steel and 5 times stronger (used in BMW i3 and McLaren 720S). But:

  • ➖ The cost of the body will increase by 10–20 times (carbon fiber hood for Toyota Supra costs ~$5,000).
  • ➖ Repair after an accident is almost impossible (the entire panel needs to be replaced).
  • ➖ Recycling carbon fiber is environmentally harmful (does not decompose, difficult to dispose of).

Option 3: Return to old technologies

You can make the body out of rigid steel St3 1.2 mm thick, as in Mercedes 1980s. But then:

  • ➖ The car will not pass crash tests Euro NCAP (passengers will be critically injured upon impact at 64+ km/h).
  • ➖ The weight will increase by 15–20%, which will make the car less economical.
  • ➖ The price will increase due to the need to strengthen the suspension and braking system.

✅ Safer for passengers in serious accidents.

✅ More economical in fuel consumption.

✅ More environmentally friendly (less CO₂ emissions).

✅ Cheaper in mass production.

-->

7. How to choose a car with the optimal body: expert advice

If you are concerned about the “softness” of modern bodies, when choosing a car, pay attention to:

  1. Crash test results - look for models with 5 stars Euro NCAP or IIHS Top Safety Pick+. For example, Subaru Outback and Volvo XC60 have some of the safest bodies in their class.
  2. Body material:
    • 🔹 For budget cars (Kia Rio, Hyundai Solaris) - look for models with galvanized body (6-10 year rust guarantee).
    • 🔹 For the premium segment (Audi A6, BMW 5 Series) - prefer aluminum + borstal (light and durable, but expensive to repair).
    • 🔹 For SUVs (Toyota Land Cruiser, Nissan Patrol) - steel body with strengthening thresholds (better for off-road, but heavier).
  • Paintwork thickness - check with a thickness gauge. Optimal: 120–150 µm on the roof and hood, 80–100 µm on the rapids. If less, there is a high probability of corrosion.
  • Availability of an active safety system — ABS, ESC, AEB (automatic braking) reduce the risk of accidents by 30–40%, which is more important than the “stiffness” of the body.

    • An example of optimal models in terms of safety/price ratio (2023–2026):

    Model Body type Euro NCAP Corrosion guarantee Average cost of body repair
    Skoda Octavia HSLA + galvanized 5 stars 12 years old 70,000–120,000 rub.
    Toyota Corolla DP steel + zinc 5 stars 10 years 80,000–150,000 rub.
    Volvo XC40 Borstal + aluminum 5 stars (98% occupant protection) 12 years old 150,000–300,000 rub.
    ⚠️ Attention: If you drive frequently on gravel or in high-accident risk situations (such as taxis), consider installing additional body protection:
    • 🛡️ Full length metal bumpers (for example, from ARB for SUVs).
    • 🛡️ PPF film (polyurethane protection) on the hood and bumper - prevents chipping from stones.
    • 🛡️ Anti-gravel coating (for example, 3M Scotchgard) for sills and wheel arches.

    This will increase the cost of the car by 30–50 thousand rubles, but will save hundreds of thousands on repairs.

    FAQ: Answers to frequently asked questions

    ❓ Why could dents be corrected on old cars, but not on new ones?

    Old bodies were made from mild low carbon steel (for example, St1 or 08kp), which is easily deformed and returns to shape when heated. Modern high-strength steels (HSLA, DP) when deformed, they change the crystal structure and become brittle. An attempt to straighten them will lead to microcracks that will weaken the body.

    In addition, new cars often use aluminum (for example, in Audi A8), which, when deformed, becomes “riveted” and cannot be straightened.

    ❓ Is it true that Chinese car bodies are thinner than European ones?

    This is a myth. Metal thickness Geely, Changan or Haval comparable to European brands (0.7–1.1 mm). The difference is quality of steel and anti-corrosion treatment. For example:

    • 🔹 Geely Coolray — body made of HSLA steel with electrogalvanization (6 year warranty).
    • 🔹 Haval Jolion — boron-containing steel in the side members, but poor processing of hidden cavities (risk of corrosion after 5–7 years).
    • 🔹 Changan CS35 Plus - full galvanization, but a thin layer of paintwork (90–110 microns versus 120–150 microns for Volkswagen).

    Chinese cars no worse in terms of metal thickness, but often lose in durability due to savings on priming and galvanizing.

    ❓ Is it possible to strengthen the body of a modern car yourself?

    Partially yes, but this will not increase security, but only protects against minor damage. Options:

    1. Installing crankcase and bumper protection - metal sheets 3–5 mm thick (for example, from Ironman 4x4) will protect against stones and light impacts, but will not help in a serious accident.
    2. Anti-gravel film sticker — PPF (polyurethane film) with a thickness of 150–200 microns will protect the paintwork from chipping, but will not strengthen the metal.
    3. Installing spacers in the engine compartment - reduces deformation during a frontal impact, but may impair the performance of crumple zones.

    What not to do:

    • ❌ Cooking additional stiffeners will violate the calculated body deformation scheme.
    • ❌ Installing “armor plates” on the door will increase the weight and shift the center of gravity.
    • ❌ Use non-original bumpers made of “thick metal” - they will not work as a crumple zone.
    ❓ Which cars have the most durable bodies in 2026?

    According to the results of crash tests and analysis of materials, the most durable bodies are those of: