By now, you should be aware that your question has no real answer, because everyone answers it somewhat differently. To some degree, I agree with parts of what everyone said. My opinion is no more right or wrong than anyone elses.
I think a dive bomb is just when a guy makes a well timed, well executed, very late brake move. In my opinion, there are two kinds of dive bombs. Legal and illegal, and which is which depends to a large degree on what club you race with, and what their rules are with regard to turning in and/or sharing the corner.
NASA has the “turn in” rule, which says if the passing car has the front tire to the driver of the car being passed AT THE NORMAL TURN IN POINT, the passing car has the right to the line. It is implicit in the rule that the passing car has to have that position under control, meaning you can’t come sliding in, crossed up, sideways, and claim the line. No matter how you say it, this is a pretty aggressive rule, and at high speeds, can leave a literally spit second decision as to who has the “right to the line”. It makes for good racing, and occasionally contact.
While I can’t cite it song and verse, PBOC’s (Porsche and BMW Owner’s Club) rule is that if you are anywhere close to someone else in a corner, you share the corner, and noone has a right to the turn or any point of it. You must coexist. PCA has a similar rule. I believe BMWCCA does as well, although I’ve never actually run with them.
In every club that I’ve ever run, the passing car has the responsibility of insuring a safe pass. Getting into contact with a far faster car in another class is just ignorant and it shouldn’t ever happen. Be aware of fast cars in other classes, hold your line, be predictable, use a point by if necessary, and get them by you efficiently.
Now, class racing for position is another story, and it can be incredibly hard to get by another racer. A well executed dive bomb is often the only way by, and I would suggest that more races are won by a late race dive bomb than with any other move, which is why I believe controlled late braking is an essential skill to perfect. This requires a good understanding of your brakes, the age of your tires (try it more often and more aggressively on fresh tires - don’t try it much at all on your 20th heat cycle), and the grip of your tires (a dive bomb doesn’t work very well at the end of an hour long session if you have abused the tires the whole time). Much goes into a quality dive bomb, but almost nothing is more satisfying.
Want to protect from a dive bomb? You can do it without being accused of a block. NASA says that you get one lane change between turns. If you are worried about someone dive bombing you, drive right down the center of the track. This leaves the passing car one of two options: 1. Try the pass even lower to the inside than you, which makes for a tight radius and slow entry and exit, so it usually doesn’t work; or 2. They have to take the outside line, which means you have the right to the track out, and there isn’t much passing on the outside of a turn. The caveat to this move is that if the other driver takes the outside line, they will likely have a higher exit speed than you, since you will have somewhat chopped off the turn with the middle of the road turn in. So, if you are protecting and turning in from mid-track, get the car to the apex so you can block that off, and track it out where you need to be, which should also block that off from the passing car.
As I said at the beginning. Nobody is going to agree with what a dive bomb is, but I don’t think it is a bad thing. Make your own decision as to what it is, and how you execute it. And certainly dont bend up a car on your rookie permit trying one!
