Car Pillar: What is A/B/C/D of the Vehicle’s Body?
By: CarBikeTech on | 5 minutes read
Which are the types of car pillars?
The body of an automobile is made of a structure that is just the same as that of a house. It has similar components, which include the roof, the pillars, and the floor. The car pillar in the vehicle stands in the near-vertical position, which supports the vehicle’s roof. However, the A-pillar and the D pillar stand inclined in some vehicles for aerodynamic reasons.
Furthermore, the manufacturers identify the car pillars from the side while moving from front to rear of the vehicle. They name the car pillars as the A-pillar, B pillar, C pillar, and D pillar. Sometimes, the vehicle designers also refer to the car pillars as 'posts.'
Why call them the A/B/C/D Pillar?
The naming system adopted for the pillars possibly originates from their shapes as seen from sides. The A-pillar resembles the shape of the alphabet “A”.
The other pillars resemble “B,” “C,” and “D” letters, respectively. Is it a mere co-incidence or designer’s creativity? If the vehicle has a stretched body structure with additional doors, such as in the case of a limousine, it gets more than one B pillars. In such a case, the manufacturers name them as B1, B2, and B3 & so on while moving from front to rear of the vehicle. For example, rescue teams communicate the names of pillars (A/B/C/D) while cutting the pillars with cutters. Hence, the naming of pillars is important while rescuing the passengers trapped in accident-damaged vehicles.
Purpose of the Car Pillar A:
Manufacturers provide the A-pillars on both sides of the vehicle. The A-pillar is made of strong steel alloys. This is to make it withstand a crash and meet safety standards. However, the vehicle’s roof and doors are the most expensive parts to carry out repairs. The blind spot occurs due to the blocking of the driver’s vision by the A-pillar. So, some car-makers made the A-pillar slimmer and chamfered to decrease the blind spots. And, thus it improves the driver’s vision.
Furthermore, B Pillar is the most complex component/structure of the vehicle body. This is because the front door closes on the B pillar while the rear door hinges onto it. The B pillar or the center pillar in vehicles is made of steel. It is welded to roof panel on top and the vehicle’s floor pan at the bottom. This pillar provides structural support to the vehicle’s roof.
Manufacturers skip the B pillar while naming other pillars. Hence, some vehicles do not have a B Pillar. The carmakers term those cars as 'Hardtops.' Instead, the vehicle specification shows the rearmost pillar as the C pillar. The manufacturers offer the Hardtops in nearly all four-door body styles. They include sedans, coupes, and wagons/MPVs. The cars without B pillars increase passenger’s visibility. However, they have limited structural support and strength. General Motors later started providing B pillars in Hardtops. Thus, it created a new vehicle body type and thereby broadened the definition of Hardtops.
Actually, the D pillar is the rearmost pillar of the vehicle’s body. However, the D pillar is provided mainly for the Station wagons or Multi-Purpose Vehicles.
Repairing the Car Pillars:
Like the house, the vehicle pillars carry the roof's weight and support the body structure of the vehicle. The pillars provide structural strength to the vehicle's body. So, repairing the vehicle body is a very critical process. Any unauthorized modifications to the pillars could jeopardize the vehicle body's structural strength and, thereby, the safety of the passengers. Hence, one needs to take great care while repairing any part of the car pillar.
Manufacturers provide specifications to maintain the critical dimensions and detailed procedures while carrying out any repairs on the vehicle body, especially the pillars. Only trained and skilled mechanics can carry out the modifications on the car pillar precisely.
Some manufacturers do not recommend repairing the car roof in case of severe damage due to an accident. In such situations, it is recommended to replace the complete body-shell if it is beyond repair. In such cases, carrying out repairs of the roof may reduce its structural strength to a large extent. This may make the vehicle unsafe and underperform.
To carry out the vehicle body's structural repairs, you need specialized equipment such as the repair bench, five-dimensional fixture sets, a pulling arm, and a three-dimensional electronic laser measuring system. These are necessary to maintain the critical dimensions and structural strength of the vehicle body.
Watch vehicle body repairing in action here:
For more information on the correct vehicle body repairing practices, please click here.