Windsheild "V" bar

[sirhk100]

I guess I'm just so used to seeing the tubes ran like this one...

http://www.radflo.com/images/RADFLO/20036901951terence%20marsh.jpg


That when I saw this one on the rail below that was upside down or opposite from most others it got me thinking. How does the load spread differ from these two designs? I've got an idea in my head of where it's going and spreading but I wanted to get some of the "pros" opinions. Why is the top one seem to me to be a more prodominate setup? I could see the one above being less intrusive on the vision then the one below but what benefits does one have over the other?

Shoot wrong photo... Well, anyways, if you did the tubes opposite of the one above, I'm trying to find the photo now...

[DougM]

I remember long ago when the Baldwins ran their class 1 cars(all 3 of them) I asked them about their "V's" in the window area. They told me it was to keep tires out of the occupant area if there were to ever submarine under a larger truck when they tapped them? Sounded reasonable to me, but now you see them in EVERY vehicle. I guess its a strength issue/ chassis design now, it would sure bug me to have to look out of those for a 250/500/ 1000 mile race but hey I dont race so what do I know..
How do racers deal with it out there?

[sweetdevil]

In the vehicles I've rode in with the "v" it kinda bothers you at first, but you get used to it after a few miles, and have more things to focus on and look at than the bars. I think it's something you just get used to.

[silverstateracer]

I thought it orginally started as a straight up and down bar in the middle, in response to one of the fast guys of the time (Herbst or Collins in Porshe powered class 1s) who either caved in or tore off the top of the car. It helped to support halo bar. Or so I thought?

[CRAIGHALL]

The "v" style would tend to support the top outer corners from caving in a violent rollover,but still leaves a large span between these points,although with a diagonal support it makes it hard to cave in the horizontal tube.

Th "A" style will support the center of the horizontal bar but does nothing to help the "A" pillar bar-but these are normally at an angle in the first place.On some truck I think there was a "M" shaped bar----

[FABRICATOR]

It really does not matter as far as strength goes, as long as the triangulation in the roof and rear "cab" area all match. It is usually done to make the front wall of the "cab" area different in order to accommodate engine, suspension, or other design requirements.

There is one other way that is strong with a ton more open area. It has a total of 3 tubes going up in front, one more on each side several inches back from the those outer front tubes, and one inside the cab near each corner. This creates a tripod pillar in each front corner. If the inside tubes are aligned with the front corner ones the driver and passenger only see one tube in the corner and the single tube in the middle of the windshield. This leaves 2 big squares or 1 huge rectanglular open area. The center tube is optional for a narrower vehicle. There have been a few cars with this design including the earlier Toyota Trophy Truck. It's a bit more work to figure out and build but the open area is almost as much as a stock pickup.

[JT_Leadfoot]

That is similar to what Robby Gordon has done.

[dadomin8r]

The center of the top tube in the roof is the weakest part. That tube would bend pretty easily in a direct hit from a rollover. The tube in the dash usually has a tube in the center going straight down and it is also welded to each tube on the side. That makes the tube in the dash strongest somewhere between the center and the outside. Therefore it makes the most sense to run the A bar.

Some of the experienced builders do opt to run them the other way on the slower trucks but I don't know why.