Car Pillar

Vehicle Body Nomenclature: What is A/B/C/D Type of Car Pillar?

Car Pillar: Which are the types of Pillars in a Car?

The body of an automobile is made of a structure that is just 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 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.

Vehicle Pillars
Vehicle Pillars

The manufacturers identify the car pillars from the side while moving from front to rear of the vehicle. The manufacturers name the car pillars as the A pillar, B pillar, C pillar and D pillar respectively. Sometimes, the vehicle designers also refer to the car pillars as posts.



Why call them the A/B/C Car Pillar?

The naming system adopted for the pillars possibly originates from their shapes as seen from sides. The A-pillar resembles the shape of alphabet “A”.

Car Pillar A
Car Pillar A
Pillar A of a Cab/Ute
Pillar A of a Cab/Ute

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 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 the accident-damaged vehicles.



Purpose of the Car Pillar A:

Manufacturers provide the A-pillars on either side of the vehicle. The A-pillar is made of strong steel alloys. This is so as to make it withstand a crash and meet safety standards. Vehicle’s roof and doors are the most expensive parts to carry out repairs. The blind spot occurs due to blocking of driver’s vision by the A-pillar. So, some car-makers make the A-pillar slimmer and chamfered to decrease the blind spots. And, thus it improves the driver’s vision.

Car Pillar B:

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.

Car Pillar B
Car Pillar B

Manufacturers skip the B pillar while naming other pillars. Hence, there are some vehicles which do not have a B Pillar. The car makers 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 the four-door body styles. They include from 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 new vehicle body type and thereby, broadens the definition of Hardtops.

Car Pillar C:

The C pillar sits behind the rear door.

Car Pillar C
Car Pillar C

The C pillar is the rearmost pillar in sedans and hatchbacks.

C Pillar of a sedan
C Pillar of a sedan

C Pillar of a HardtopC Pillar of a Hardtop

Car Pillar D:

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.

Car Pillar D
Car Pillar D

Repairing the Car Pillar:

Same as the house, the vehicle pillars carry the weight of the roof and support the body structure of the vehicle. The pillars provide structural strength to the body. So, repairing the vehicle body is a very critical process. Any unauthorized modifications to the pillars could jeopardize the structural strength of the vehicle body and thereby, the safety of the vehicle. 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 of 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 repairs. To carry out structural repair of the vehicle body, you need specialized equipment such as the repair bench, five-dimensional fixture sets, a pulling arm and three-dimensional electronic laser measuring system. This is necessary to maintain critical dimenstions and structural strength of the vehicle body.

Watch vehicle body repairing in action here:

For more information on vehicle body repairing, please click here.

Read more: Weight Loss Therapy for cars>>

Don't miss out on Automotive Knowledge