I have seen videos of cars that do not have a B-pillar. I think it looks much better because it reduces the separation between each row. It’s hard for me to understand that a roof is heavy enough that it needs a support in the middle.
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The longer a car’s roofline is, the more support it will tend to require along its length. It isn’t owing to the weight of the roof panel, it has to do with crash safety. It is possible to build a roof that doesn’t require a b pillar, but that makes construction more expensive and adds weight to the roof which can have a negative effect on handling.
It’s not about supporting the weight of the roof, it’s about supporting the weight of the rest of the car in the event of a rollover. Also a convenient place for the doors to seal against.
Imagine your vehicle in a high-speed multiple rollover.
Recalculate how “heavy” the roof is as it impacts the road on each roll.
Expand your understanding.
-les
The roof isn’t heavy. It needs to be strong because it acts as a brace for the rest of the frame. You need something either above or below to prevent vertical flexing, and convertibles usually put an X-brace below.
Structural rigidity is a key factor. It provides for a structurally more sound body frame than a car without one.
In some countries, it became illegal to have doors that opened at the front (hinged at the back). That is because if it was slightly opened while moving, the airflow would pull it wide open. Also, it made the leading door edge sharp — it you were hit by a door hinged at the back you would be hurt by the panel of the door, but you wouldn’t get chopped by the edge.
It you don’t have the B-pillar, you can’t hinge the rear door at the front, and you don’t have a mount point for the front seat belt.
Taxis in London still have the rear doors hinged at the back, but they have automatic locks and a professional driver.
They are a lot less rigid. A convertible won’t have a b-pillar so to get similar structural rigidity you have to brace the frame with cross members to make up for the fact that the roof is not providing any structural support. This is, assuming of course, we are talking about a unibody constructed car.
People mentioned that the b pillar is good for helping you not die in a rollover, that is true. However, you don’t need a b pillar for that, modern convertibles have things that are similar to rollover cages that go behind the driver’s head so if you do end up wrong side up the weight of the car doesn’t crush your head.
Additionally, hanging rear doors is trivial if you have a b pillar, a huge pain if you have to rear or top hinge them. It is why there are so very few 4 door convertibles. It isn’t impossible to build, but the juice isn’t worth the squeeze.
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